A method of constructing a building

Abstract

There is disclosed a method of constructing a building comprising at least one modular building unit, as well as a building and a building system comprising at least one modular building unit, and a modular building unit for such a building. One method disclosed in the document is for constructing a building (10) comprising at least one modular building unit (12a, 12b), and comprises the steps of: constructing a foundation (60) for the building, including providing the foundation with a load bearing structure (62) and thermal insulation (64); providing at least one modular building unit (12a) comprising an internal volume (46) defining at least one room (100, 104), the internal volume containing a wet facility and defining at least part of a circulation space (36) which provides an access function for the building; and locating the at least one modular building unit on the foundation so that the load bearing structure of the foundation provides structural support for the modular building unit, and so that the thermal insulation of the foundation thermally insulates the modular building unit relative to the ground.

Description

[0001] A METHOD OF CONSTRUCTING A BUILDING

[0002] The present invention relates to methods of constructing a building comprising at least one modular building unit, to buildings and building systems comprising at least one modular building unit, and to modular building units for a building. The invention also relates to a foundation for such buildings.

[0003] In the construction industry, buildings (particularly residential buildings) have conventionally been constructed using an ‘on-site’ approach. Generally speaking, this has involved shipping building materials and components to a site defining a location for the building, for example a plot on a site which is to provide a plurality of separate buildings, such as houses or other residential buildings. The building materials and components are then used to construct the finished building at the site.

[0004] Conventional construction techniques for producing residential buildings are varied, and include traditional blockwork / masonry, timber frame, stick-built, and metal frame-based approaches. These all suffer from certain disadvantages, including that the buildings can be comparatively slow to construct, and often have a considerable environmental impact. All of the outlined approaches require the presence of large teams of skilled tradespeople on the site, which can be difficult to manage, and costly. Quality control of finished buildings can also be challenging, due to variations in skill levels of tradespeople.

[0005] Modern methods of construction (MMC) have been developed, in an effort to address these disadvantages, and typically involve a modular approach. Modular building units are constructed in a dedicated facility, which is typically located off-site, and so distanced from a final location for the building. The modular building units are constructed to a substantially finished form in the facility, shipped to the site (e.g. by road / rail), and connected in a predetermined fashion to form the completed building.

[0006] Whilst modular approaches address a number of the disadvantages associated with conventional construction techniques, numerous problems remain. In particular, in all fully modular approaches, there is a requirement to manufacture, store and ship large volume modular building units, which units together form the entire volume of the finished building. This raises significant logistical challenges, and is not always cost-effective.

[0007] For example, a modular approach can be effective for more complex modular units, such as those containing wet facilities (WC / washroom, bathroom etc.). There are however fewer benefits for less complex modular units, such as those forming simple living space (e.g. bedrooms and living rooms). The costs involved in storing and transporting such modular units can outweigh other benefits. In addition, the units are size -restricted by factory, handling and transport limitations, which can reduce design choice / flexibility and living space options, and increase complexity.

[0008] The present applicant has developed hybrid buildings and associated construction methods which seek to address these issues, by combining the best aspects of on-site and off-site construction techniques. More complex parts of a building are provided in a modular -type building unit manufactured away from its final location. Less complex parts (e.g. simple living space) are constructed on site. The building is completed by connecting the on-site and off-site parts at the final location. The hybrid buildings and construction methods which have been developed are disclosed in International patent publication nos. WO2022 / 243696, WO2022 / 243695, WO2022 / 243694, WO2022 / 243693 and WO2023 / 222853.

[0009] Whilst these hybrid buildings and construction methods offer numerous advantages over both conventional and fully modular approaches, it is desired to make further improvements. In particular, buildings constructed using conventional techniques typically comprise a foundation which supports structural components of the building, for example brick / block load bearing walls, a timber frame, or metal structural elements. Insulating material is positioned within the building structure, to resist thermal energy transfer between the interior and exterior of the building. For example, in brick and block structures, a cavity is usually provided between inner and outer wall skins, which is filled with an insulating material.

[0010] Thermal bridging can however occur between the foundation and the structural components. This is mitigated by the thermal insulation, which reduces thermal energy transfer between the structural components and the building interior. Materials used to form the structural components can also be relatively insulative, for example timber forming a structural frame. In the case of metal structural components however, which have a relatively high thermal conductivity, significant thermal bridging can occur.

[0011] Modular building units usually have a structural frame, which is often metal (e.g. cold-rolled steel). At least some modular building units in a modular building are positioned directly on a foundation structure, for example a concrete foundation pad. Thermal bridging can be a significant problem, due to the metal structural elements of the frame. Thermal energy transfer can occur between the modular building unit and the foundation (and so the ground on or in which the foundation structure is positioned). A floor portion of the metal structural frame is therefore heavily insulated. The floor portion has to be comparatively deep in order to accommodate the insulation, which is generally undesirable, adding both cost and complexity. Thermal bridging can still occur, with resultant thermal energy loss, by transfer through the metal structural elements (which extend through a depth of the floor portion).

[0012] According to a first aspect of the present invention, there is provided a method of constructing a building comprising at least one modular building unit, the method comprising the steps of: constructing a foundation for the building, including providing the foundation with a load bearing structure and thermal insulation; providing at least one modular building unit comprising an internal volume, the internal volume optionally defining at least one room, the internal volume optionally containing a wet facility and optionally defining at least part of a circulation space which provides an access function for the building; and locating the at least one modular building unit on the foundation so that the load bearing structure of the foundation provides structural support for the modular building unit, and so that the thermal insulation of the foundation thermally insulates the modular building unit relative to the ground. By thermally insulating the foundation, it may be possible to reduce a depth of insulation provided in the modular building unit (particularly in a floor portion of the unit), and potentially to dispense with insulation altogether, in at least the floor portion. This may provide the added benefit that a depth of the floor portion can be reduced, relative to prior modular building units, with consequential benefits in terms of material / cost savings, weight savings and design flexibility. On the latter point in particular, a requirement to have a relatively deep floor portion in a conventional modular building unit (for accommodating insulation) may make it necessary to increase a total height dimension of the modular building unit, and / or to reduce an internal floor to ceiling dimension, both of which may restrict design choice and / or may be aesthetically or spatially undesirable. Additionally, a floor level of a remainder of the building (which as discussed below, may be at least partly of a non-modular construction) may have to be brought up to that of the module, adding cost / complexity.

[0013] The method may comprise arranging said modular building unit so that it defines (suitably completely or entirely defines) at least one room. The method may comprise arranging the modular building unit so that it comprises one or more wall, which may define a boundary or boundaries (optionally all boundaries) of said room. The at least one room may contain the wet facility. The internal volume may be arranged to define a plurality of rooms. One or more further room of the plurality of rooms may be arranged to contain a further wet facility.

[0014] The method may comprise arranging the at least one modular building unit so that it defines at least part of a perimeter of the building, which may be an external perimeter. The method may comprise arranging a wall or walls of the modular building unit to define said part of the perimeter. The wall or walls may be arranged so that an external surface of the wall or walls defines an external surface of the building, or may be clad or surfaced with an exterior surface finish / coating (e.g. panels, brick slips, cementitious render).

[0015] The method of the invention may comprise providing at least one modular building unit with a floor portion. The floor portion may define a floor of said unit. The floor portion may comprise a floor portion support structure. The floor may be positioned on and / or defined by said support structure. The floor portion support structure may describe, define, or have, a floor perimeter.

[0016] The method may comprise forming the floor portion, in particular the floor portion support structure, from materials having a thermal conductivity of no less than about 0.04W / m.K, optionally from materials having a thermal conductivity in excess of 0.04W / m.K. All materials present in / forming the floor portion may have a thermal conductivity no less than this value. Insulating materials used in building construction typically have relatively low thermal conductivity values, in the range of about 0.02 to 0.04W / m.K. Examples include mineral wool, polyurethane, and expanded and extruded polystyrene (XPS). The floor portion of the modular building unit of the invention may be insulated relative to the ground by the insulation material of the foundation. This may have the result that the floor portion can be constructed so that it is free from (or substantially free from) insulation material, and so of materials having thermal conductivities in excess of the above value. This may address the disadvantages discussed above, providing benefits including reduced manufacturing cost / complexity, and reduced floor depth (and so greater design freedom).

[0017] Materials which may be used in constructing the floor portion, and which may have thermal conductivities no less than about 0.04W / m.K, may include: metallic materials (metals and metal alloys, particularly steel and aluminium); timber / wood materials; cementitious materials (e.g. concrete); resin materials (e.g. polymeric resins); composite materials (e.g. glass or other fibre based resinous composites); and combinations thereof. These may be used variously for forming structural elements (support columns, beams, floor panels etc.) as well as surfacing / finishing elements (e.g. such as decorative floor panels).

[0018] The floor portion may be free from insulation / insulation material. The method may comprise arranging said modular building unit so that there is no insulation / insulation material disposed within the floor perimeter. In conventional modular building units, it is typically necessary to provide insulation / insulation material within a perimeter of a floor support structure portion of the unit, for example in apertures between members forming the support structure (such as members of a frame forming the portion). This can have the disadvantages discussed above.

[0019] The at least one modular building unit may comprise a support structure. The support structure may comprise, or may take the general form of, a frame or framework structure. The support structure may comprise at least said floor portion support structure, and a plurality of wall portion support structures (suitably at least four, e.g. where the unit is generally quadrilateral shape in plan view). The support structure may also comprise a ceiling portion support structure. The or each support structure portion may take the general form of a frame. Suitable materials for forming the support structure can include metals / metal alloys, and wood / timber, as well as combinations of any of these options. In a support structure of a metallic (e.g. metal / metal alloy) material, options for forming the support structure include cold-forming (e.g. pressed, stamped or rolled, and which may form a light gauge steel framed - LGSF - structure), hot-forming (e.g. hot rolled), and combinations of these. Another option for the support structure is forming it as a panelised structure, comprising for example structural insulated panels (SIPs), although these would not typically be employed for the floor portion, which may not need to be insulated.

[0020] The method may be a method of constructing a hybrid building which generally comprises a site constructed section and a modular building unit. The method may comprise: constructing a first building section at a final location for the building; at a location away from the final location, constructing the at least one modular building unit to a substantially assembled form; transporting the at least one modular building unit to the final location in the substantially assembled form; and connecting the first building section and said modular building unit to form the building. Said modular building unit may form a second building section.

[0021] The first building section may be an on-site construction. This could be taken to mean that the first building section is constructed at the site (suitably at a final location for the building) using an arrangement of parts, components and / or materials which are provided at the site. This may involve forming an internal volume (suitably an entire internal volume) of the first building section at the site, in particular at the final location. This is in contrast for example to modular buildings which are assembled on site (at a final location) using building units or sections that have been constructed off-site (e.g. in a construction facility or factory) and which, in their constructed form, define part of an internal volume of the finished building.

[0022] The method may comprise constructing the first building section at the final location using a kit of building materials (e.g. blocks, timber frame components, metal structural elements), which may be provided at the site. A range of construction options for the first building section includes: a blockwork / masonry construction; a timber frame (and blockwork / masonry, or cladding, construction); a metal frame construction (optionally comprising panels coupled to the frame, which may be composite panels comprising insulation material); a structure comprising structural insulated panels (SIPs); a time-setting 3D printed construction; and combinations thereof.

[0023] The method may comprise arranging the building so that it provides living space. This should be taken to mean an area within which a person can live, and which may exclude: storage areas (e.g. cupboards, closets, garage); technical areas (e.g. boiler rooms or cupboards, water storage tank cupboards); attics, lofts, basements and cellars (unless they provide a livable space e.g. a bedroom); and outdoor spaces (e.g. decks, patios, balconies and verandas). Living spaces will typically be covered or enclosed (in the completed building), and heated. A non-limiting list of rooms or areas that may fall within the definition of ‘living space’ includes: kitchens, bedrooms, living / sitting rooms and leisure areas, dining rooms, bathrooms, W / Cs or washrooms, and ensuites. A majority of living space within the constructed building may be defined by the first (site constructed) building section. In particular, some or all of a kitchen, bedroom(s), living / sitting room and other leisure areas, office and dining areas, may be provided within the first building section.

[0024] The method may comprise arranging the at least one modular building unit so that it provides at least some living space. The method may comprise arranging the living space provided by said modular building unit to define one or more wet facility, e.g. in the form of a bathroom, W / C or washroom, and / or ensuite. The living space may be arranged to define at least part of other areas or rooms, including at least part of a bedroom or kitchen.

[0025] The method may be a method of constructing a residential building. In the context of the invention, this should be taken to mean a building in which sleeping accommodation is provided for normal residential purposes, preferably with cooking and dining facilities. Non-limiting examples of residential buildings falling with the scope of the invention include houses (e.g. detached, semi-detached, and terraced as well as a single storey house / bungalow), and apartments / flats.

[0026] The method may be a method of constructing a modular building comprising a plurality of modular building units which together form an entire (or substantially an entire) internal volume of the building. The modular building units may be arranged in a predetermined configuration to form the building, each such unit typically connected to at least one further such adjacent unit. The modular building units may form all of the living space for the building. At least some of the modular building units may be located on the foundation, suitably in direct contact with the foundation.

[0027] The method may comprise providing a plurality of modular building units, which may be configured to be fitted or coupled together (but could be spaced apart and / or out of contact). The method may comprise locating a first one of the units on the foundation, and locating a second unit on the first unit so that the second unit is supported by the first unit (and so indirectly by the load bearing structure of the foundation). The method may comprise connecting said units together at the final location, for example by stacking at least one such unit on top of at least one other such unit (in direct contact with each other, or in indirect contact e.g. with a structural member or layer between the units). Said units may comprise a lower modular building unit and an upper modular building unit. It will be understood that, in such an arrangement of stacked units, the foundation thermal insulation may thermally insulate the lower such unit relative to the ground, and so inherently also said upper unit (which rests upon the lower such unit). Said upper unit may therefore also comprise a floor portion which is constructed from materials having the thermal conductivity indicated above, and / or which is free from insulation / insulation material.

[0028] Where there are a plurality of modular building units: only one (or only some) of the units may comprise a wet facility; and / or only one (or only some) of the units may define a circulation space, or at least part of a circulation space. This may apply particularly where the method involves constructing a modular building from a plurality of modular building units. At least one, and suitably a plurality, of the modular building units may define living space.

[0029] The method may comprise arranging the at least one modular building unit so that it comprises all, or at least a majority of, the wet facilities for the building. A wet facility or facilities contained in the internal volume of said modular building unit may include one or more of: a bathroom; a W / C or washroom; an ensuite; water supply for other purposes including to a kitchen; and sewerage / wastewater connections.

[0030] The circulation space (which may also be referred to as a circulation zone or transition space / zone) may be arranged to provide one or more access function selected from the group comprising: access between upper and lower living spaces of the first building section (e.g. between upper and lower storeys of the section, via a staircase, or a lift shaft and lift in the unit); access between a first living space and at least one further living space of the first building section, said living spaces optionally being isolated from one another within the first building section and optionally on a same level / storey of the section (e.g. via a hallway / landing and one or more doorway or walkway); and access into the first building section from the outside of the building, and so access into the building from its exterior (e.g. via one or more doorway or walkway, and optionally also a hallway).

[0031] The circulation space may be defined wholly by the (or a) modular building unit. For example, where the circulation space provides access into the first building section from the outside of the building, the space may be defined wholly by a single unit. The circulation space may be defined in combination by a plurality of modular building units. For example, where the circulation space provides access between upper and lower living spaces, two or more units may cooperate to define the access, e.g. each may form part of a staircase or lift shaft.

[0032] The step of constructing the foundation may comprise positioning the thermal insulation on or in the ground, which may be at a site forming a final location for the building. The thermal insulation may provide a surface on which the load bearing structure can be positioned, which may be a continuous (or at least substantially continuous) surface. The load bearing structure may be positioned on the thermal insulation, suitably on said surface, following positioning of the thermal insulation on or in the ground. In this way, the load bearing structure may be insulated relative to the ground by the thermal insulation, so that thermal energy transfer between the load bearing structure and the ground is resisted. This in turn may insulate the modular building unit (located on the foundation) relative to the ground.

[0033] Suitable commercially available insulation materials include Isoquick® insulation blocks commercially available in the UK from Build Homes Better Ltd, and which can be arranged to form an insulation raft or pad. The blocks are formed from a water-resistant polymeric foam material, in particular Peripor®, which is a water- resistant foam available from BASF SE. Other options include extruded polystyrene foams (XPS).

[0034] In a variation, the step of constructing the foundation may comprise positioning the load bearing structure on or in the ground, which may be at a site forming a final location for the building. The load bearing structure may provide a surface on which the thermal insulation can be positioned, which may be a continuous (or at least substantially continuous) surface. The thermal insulation may be positioned on the load bearing structure, suitably on said surface, following positioning of the load bearing structure on or in the ground. In this way, the at least one modular building unit may be insulated relative to the ground by the thermal insulation, so that thermal energy transfer between the unit and the ground is resisted. It will be understood that, in this scenario, the thermal insulation may be required to have sufficient load bearing capacity to bear structural loads (particularly e.g. point loads) imparted upon it by the at least one modular building unit, and indeed by a remainder of the building.

[0035] Numerous options exist for forming the load bearing structure. One option comprises forming a continuous (or substantially continuous) platform, raft or pad defining the load bearing structure. Said pad may be of a cementitious material, optionally concrete. Said pad may comprise integral structural reinforcing elements, such as a mesh or grid of reinforcing bars (‘rebar’). Another option comprises forming a plurality of separate support elements, which may together form at least part of the load bearing structure. The support elements may be arranged so that they are spaced apart and / or not physically connected (at least by material forming the foundation itself), or may be positioned next to / adjacent one another. The support elements may take the form of pads, piers, piles, columns or the like, or elongate beams. The support elements may be of a cementitious material as described above. In other options, combinations of the above techniques may be employed, including in or forming different layers of the structure. The method may comprise forming the load bearing structure at a site for the building, for example employing a time-setting cementitious material. In a variation, support elements arranged to form the load bearing structure may be preformed away from a site forming the final building location, and the foundation formed at the site e.g. by arranging the support elements in a predetermined configuration.

[0036] Where the load bearing structure comprises a plurality of support elements, the thermal insulation may be applied as a continuous (or at least substantially continuous) layer on the ground below the support elements, or extending over the support elements.

[0037] The step of constructing the foundation may further comprise providing the foundation with a moisture barrier. The moisture barrier may act to resist moisture ingress into the modular building unit from the ground on or in which the foundation is positioned. The moisture barrier may take the form of at least one barrier layer. The method may comprise arranging said barrier layer so that it provides a continuous sheet extending across a surface of the load bearing structure and / or the thermal insulation, which surface may be an upper or lower surface.

[0038] A plurality of barrier layers may be provided, for example a lower barrier layer and an upper barrier layer. Any suitable arrangement of the barrier layers within the foundation may be employed. For example, a lower barrier layer may be positioned below the lowermost one of the load bearing structure and the thermal insulation, and an upper barrier layer may be positioned: a) between an upper surface of the lowermost one of the load bearing structure and the thermal insulation and a lower surface of the uppermost one of the load bearing structure and the thermal insulation; and / or b) on an upper surface of the uppermost one of the load bearing structure and the thermal insulation.

[0039] The moisture barrier (in particular said barrier layer or layers) may take any suitable form known in the field of the invention. Particularly suitable options may include: a moisture resistant sheet, which may be a substantially impermeable membrane e.g. of a polymeric material such as polyethylene, for example those available from British Polythene Limited under the Visqueen™ brand; and a breathable water resistant membrane such as those available from DuPont de Nemours, Inc. under the Tyvek® brand.

[0040] The method may comprise providing one or more of the load bearing structure, the thermal insulation, and the moisture barrier, as a layer of or in the foundation.

[0041] The step of constructing the foundation may further comprise providing the load bearing structure in combination with, or so that it defines, the thermal insulation. In other words, the load bearing structure and the thermal insulation may be combined into, or provided as, a single (i.e. unitary) or continuous product / feature. Thus a load bearing structure may be provided having sufficient insulative properties to provide the required thermal barrier, or alternatively thermal insulation may be provided having the required structural load bearing capacity. Suitable options may include constructing the foundation at least partly from load bearing heat insulating building blocks / members, such as those available from Marmox (UK) Ltd under the Thermoblock™ brand, and Creagh Concrete Products Ltd under the Spantherm™ brand.

[0042] It is conceivable that the thermal insulation can be provided in combination with, or so that it defines, a moisture barrier. In other words, the thermal insulation and the moisture barrier may be combined into or provided as a single (i.e. unitary) product / feature, for example by forming the thermal insulation of an inherently moisture resistant material. Generally speaking however, legislation requires that a specific e.g. barrier membrane be provided, and so the thermal insulation and moisture barrier will typically be separate.

[0043] The different parts of the foundation, i.e. the load bearing structure, thermal insulation and moisture barrier (where present) may be arranged in any suitable combination / configuration. For example, considered from the ground up, the foundation may comprise: thermal insulation, load bearing structure and moisture barrier; load bearing structure, thermal insulation and moisture barrier; moisture barrier, thermal insulation and load bearing structure; or thermal insulation, moisture barrier and load bearing structure. It will be understood however that the moisture barrier may comprise a plurality of layers as discussed above.

[0044] The step of constructing the foundation may comprise providing the foundation with an upper surface, and seating (directly or indirectly) said modular building unit on the upper surface. The upper surface may be provided by any suitable part of the foundation, and this will of course depend upon the specific order of the foundation parts. For example, in a foundation comprising (from the ground up) thermal insulation, load bearing structure and moisture barrier), the upper surface may be provided by the moisture barrier.

[0045] The method may comprise arranging a first portion of the foundation insulation so that it has at least one characteristic which is different from a corresponding characteristic of a further portion of the foundation insulation. The method may comprise providing the first portion of the foundation insulation with at least one of a lower load bearing capacity, and a lower thermal conductivity, compared to the further portion of the foundation insulation. The method may comprise arranging the first portion of the foundation insulation so that it supports a floor portion of the first building section, and arranging the second portion of the foundation insulation so that it supports the modular building unit, optionally a floor portion of the modular building unit.

[0046] According to a second aspect of the present invention, there is provided a building comprising: a foundation comprising a load bearing structure and thermal insulation; and at least one modular building unit comprising an internal volume optionally defining at least one room, the internal volume optionally containing a wet facility and optionally defining at least part of a circulation space that provides an access function for the building; in which the at least one modular building unit is located on the foundation so that the load bearing structure provides structural support for the modular building unit, and so that the thermal insulation thermally insulates the modular building unit relative to the ground. The at least one modular building unit may define (and suitably may completely or entirely define) at least one room. The at least one modular building unit may be arranged so that it comprises one or more wall, which may define a boundary or boundaries (optionally all boundaries) of said room. The at least one room may contain the wet facility. The internal volume may be arranged to define a plurality of rooms. One or more further room of the plurality of rooms may be arranged to contain a wet facility.

[0047] The at least one modular building unit may be arranged to define at least part of a perimeter of the building, which may be an external perimeter. A wall or walls of the modular building unit may be arranged to define said part of the perimeter. The wall or walls may be arranged so that an external surface of the wall or walls defines an external surface of the building, or may be clad or surfaced with an exterior surface finish / coating (e.g. panels, bricks slips, cementitious render).

[0048] The at least one modular building unit may have a floor portion. The floor portion may comprise a floor portion support structure. The floor portion support structure may describe, define, or have, a floor perimeter.

[0049] The floor portion, in particular the floor portion support structure, may be of a material or materials having a thermal conductivity of no less than about 0.04W / m.K, and optionally a thermal conductivity in excess of 0.04W / m.K. The floor portion may be free from insulation material, and so of materials having thermal conductivities in excess of this value. The floor portion may be arranged so that there is no insulation / insulation material disposed within the perimeter of the support structure.

[0050] The at least one modular building unit may comprise a support structure. The support structure may comprise at least said floor portion support structure, and a plurality of wall portion support structures (suitably at least four, e.g. where the unit is generally quadrilateral shape in plan view). The support structure may also comprise a ceiling portion support structure. The or each support structure portion may take the general form of a frame. Another option for the support structure is an at least partly panelised structure, comprising for example structural insulated panels (SIPs).

[0051] The building may be a hybrid building generally comprising a site constructed section, which may form a first building section, and the at least one modular building unit. The first building section may be constructed at a final location for the building. The at least one modular building unit may form a second building section of the building. The at least one modular building unit may be constructed or constructable to a substantially assembled form at a location away from the final location, may be transportable to the final location in the substantially assembled form, and may be connectable to the first building section to form the building. The modular building unit, and optionally the second building section defined at least partly by the modular building unit, may be enclosed or enveloped by or within the first building section.

[0052] A majority of living space within the constructed building may be defined by the first (site constructed) building section. In particular, some or all of a kitchen, bedroom(s), living / sitting room and other leisure areas, office and dining areas, may be provided within the first building section. The at least one modular building unit (or one or more such unit where the building comprises a plurality of the units) may provide at least some living space. The living space provided by said modular building unit may define one or more of a bathroom, W / C or washroom, and ensuite. The living space may define at least part of other areas or rooms, including at least part of a bedroom or kitchen.

[0053] The building may be a residential building. Non-limiting examples of residential buildings are defined elsewhere in this document, and include houses and apartments / flats.

[0054] The building may be a modular building comprising a plurality of modular building units which together form an entire (or substantially an entire) internal volume of the building. The modular building units may be arranged in a predetermined configuration, each such unit typically connected to at least one further such adjacent unit. The modular building units may be fitted or coupled together. A first one of the units may be located on the foundation, and a second unit may be located on the first unit so that the second unit is supported by the first unit (and so by the load bearing structure). The units may be stacked, at least one such unit located on top of at least one other such unit (in direct or indirect contact with each other). Said units may comprise a lower modular building unit and an upper modular building unit. Said upper unit may also comprise a floor portion which is free from insulation / insulation material.

[0055] Where there are a plurality of modular building units: only one (or only some) of the units may comprise a wet facility; and / or only one (or only some) of the units may define a circulation space, or at least part of a circulation space. This may apply particularly to a fully modular building, constructed from a plurality of modular building units.

[0056] The at least one modular building unit may be configured so that the circulation space provides one or more access function selected from the group comprising: access between upper and lower living spaces of the first building section; access between a first living space and at least one further living space of the first building section (said living spaces optionally being isolated from one another); and access into the first building section from the outside of the building, and so into the building from its exterior. The circulation space may be defined wholly by the (or a) modular building unit. The circulation space may be defined in combination by a plurality of modular building units.

[0057] The thermal insulation may be positioned on or in the ground, suitably at a site forming a final location for the building, and may provide a surface on which the load bearing structure is positioned (or supported). In a variation, the load bearing structure may be positioned on or in the ground, suitably at a site forming a final location for the building, and may provide a surface on which the thermal insulation is positioned (or supported). The thermal insulation may then have sufficient load bearing capacity to bear structural loads imparted upon it by the at least one modular building unit, and by a remainder of the building.

[0058] The load bearing structure may comprise a continuous (or substantially continuous) platform, raft or pad defining the structure, optionally of a cementitious material. Said pad may comprise integral structural reinforcing elements. The load bearing structure may comprise a plurality of separate support elements, which may together form at least part of the load bearing structure. The support elements may be arranged so that they are spaced apart and / or not physically connected, or may be positioned next to / adjacent one another. The support elements may take the form of pads, piers, piles, columns or the like, or alternatively elongate beams.

[0059] The foundation may further comprise a moisture barrier, which may take the form of at least one barrier layer. The barrier layer may provide a continuous sheet extending across a surface of the load bearing structure and / or the thermal insulation, which surface may be an upper or lower surface. A plurality of barrier layers may be provided, for example a lower barrier layer and an upper barrier layer. A lower barrier layer may be positioned below the lowermost one of the load bearing structure and the thermal insulation. An upper barrier layer may be positioned: a) between an upper surface of the lowermost one of the load bearing structure and the thermal insulation, and a lower surface of the uppermost one of the load bearing structure and the thermal insulation; and / or b) on an upper surface of the uppermost one of the load bearing structure and the thermal insulation.

[0060] The load bearing structure may be provided in combination with, or may define, the thermal insulation. Thus the load bearing structure and the thermal insulation may be combined into, or provided as, a single (i.e. unitary) product / feature. The load bearing structure may at least partly comprise load bearing heat (or thermal) insulating building blocks / members.

[0061] The thermal insulation may be provided in combination with, or may define, a moisture barrier. The thermal insulation and the moisture barrier may therefore be combined into, or provided as, a single (i.e. unitary) product / feature, for example of an inherently moisture resistant material.

[0062] Considered from the ground up, the foundation may comprise: thermal insulation, load bearing structure and moisture barrier; load bearing structure, thermal insulation and moisture barrier; moisture barrier, thermal insulation and load bearing structure; or thermal insulation, moisture barrier and load bearing structure. It will be understood however that the moisture barrier may comprise a plurality of layers as discussed above.

[0063] The foundation may comprise an upper surface, and said modular building unit may be seated (directly or indirectly) on the upper surface. The upper surface may be provided by any suitable part of the foundation.

[0064] Further features of the building may be derived from the text set out elsewhere in this document, particularly in or with reference to the method of the first aspect of the invention.

[0065] According to a third aspect of the present invention, there is provided a building system comprising: a foundation comprising a load bearing structure and thermal insulation for a building; and at least one modular building unit configured to form part of the building, the at least one modular building unit comprising an internal volume optionally defining at least one room, the internal volume optionally containing a wet facility and optionally defining at least part of a circulation space that provides, in use, an access function for the building; in which the at least one modular building unit is configured to be located on the foundation so that, in use: the load bearing structure provides structural support for the modular building unit; and the thermal insulation thermally insulates the modular building unit relative to the ground.

[0066] The building system may be configured to form a building according to the first aspect of the present invention. The system may therefore be a hybrid building or building construction system (particularly a hybrid residential building system) generally comprising a site constructed section, which may form a first building section of the building, and the at least one modular building unit, which may form a second building section of the building.

[0067] Further features of the building system may be derived from the text set out elsewhere in this document, particularly in or with reference to the method of the first aspect of the invention, and the building of the second aspect.

[0068] According to a fourth aspect of the present invention, there is provided a modular building unit configured to form part of a building, the modular building unit comprising: a wet facility ; at least part of a circulation space that provides, in use, an access function for the building; and a floor portion constructed from material(s) having a thermal conductivity of no less than about 0.04W / m.K

[0069] The floor portion may comprise / may be constructed from, and may consist entirely of, materials having such a thermal conductivity. The material(s) forming the floor portion may have a thermal conductivity in excess of 0.04W / m.K. The floor portion may be free from insulation material, and so of material(s) having thermal conductivity in excess of the above value. Materials which may be used in constructing the floor portion, and which may have thermal conductivities no less than about 0.04W / m.K, are detailed elsewhere in this document.

[0070] The modular building unit may comprise an internal volume, which may contain the wet facility, and / or which may define the circulation space. The internal volume may define (and suitably may completely or entirely define) at least one room. The modular building unit may be arranged so that it comprises one or more wall, which may define a boundary or boundaries (optionally all boundaries) of said room. The at least one room may contain the wet facility. The internal volume may be arranged to define a plurality of rooms. One or more further room of the plurality of rooms may be arranged to contain a further wet facility.

[0071] The at least one modular building unit may be arranged, in use, to define at least part of a perimeter of the building, which may be an external perimeter. A wall or walls of the modular building unit may be arranged to define said part of the perimeter. The wall or walls may be arranged, in use, so that an external surface of the wall or walls defines an external surface of the building, or may be configured to be clad or surfaced with an exterior surface finish / coating (e.g. panels, bricks slips, cementitious render). The modular building unit may be configured to be located, in use, on a foundation of the building, the foundation optionally comprising a load bearing structure and thermal insulation.

[0072] The floor portion may comprise a floor portion support structure. The floor portion support structure may describe, define, or have, a floor perimeter. The modular building unit may be arranged so that there is no insulation (or insulation material) disposed within the perimeter of the floor portion support structure.

[0073] The modular building unit may have any of the further features, and / or may form part of a building / system having any of the further features, set out elsewhere in this document, particularly in or with reference to the method of the first aspect of the invention, and the building / system of the second and third aspects.

[0074] According to a fifth aspect of the present invention, there is provided a method of constructing a building comprising at least one modular building unit, the method comprising the steps of: providing a first building section at a final location for the building, including arranging the first building section so that it defines an internal volume; constructing a modular building unit to a substantially assembled form at a location which is distanced from the final location, including: providing the modular building unit with a floor portion comprising material having a thermal conductivity of no less than about 0.04W / m.K; arranging the at least one modular building unit so that it comprises an internal volume; providing a wet facility in the internal volume; and arranging the internal volume so that it defines at least part of a circulation space which provides at least one access function for the building during use, the access function optionally selected from the group comprising: access between upper and lower living spaces defined by the internal volume of the first building section; access between a first living space and at least one further living space defined by the internal volume of the first building section, the living spaces optionally provided in a same storey of the first building section; and access into the first building section from the outside of the building; transporting the modular building unit to the final location in the substantially assembled form; and connecting the modular building unit with the first building section at the final location, to define at least part of the building.

[0075] The access which is provided between the upper and lower living spaces of the first building section may be between living spaces on or defined by upper and lower storeys of said section, and may be achieved via a staircase, or a lift shaft and lift, in the modular building unit. The first and at least one further living space may be isolated from one another within the first building unit, and may be on a same level of the section. Such access may be via a hallway / landing and one or more doorway or walkway. The access which is provided into the first building section from the outside of the building may provide access into the building from its exterior, and may be achieved via one or more doorway or walkway, and optionally also a hallway.

[0076] The method may comprise constructing at least one further modular building unit to a substantially assembled form at the distanced location, transporting said modular building unit to the final location in the substantially assembled form, and connecting said modular building unit with one or more of: the first building section; and another modular building unit, at the final location.

[0077] The first building section may be a site construction as described elsewhere in this document, or may itself be a modular building unit, and / or formed from a plurality of modular building units.

[0078] The method may further comprise: constructing a foundation for the building, including providing the foundation with a load bearing structure and thermal insulation; and locating the at least one modular building unit on the foundation so that the load bearing structure of the foundation provides structural support for the modular building unit, and so that the thermal insulation of the foundation thermally insulates the modular building unit relative to the ground.

[0079] The method may comprise providing the floor portion with a floor portion support structure. The floor portion support structure may be arranged to describe, define, or have, a floor perimeter. The method may comprise arranging said modular building unit so that there is no insulation / insulation material disposed within the perimeter.

[0080] The floor portion may comprise, and may consist entirely of, material having the stated thermal conductivity. The material(s) forming the floor portion may have a thermal conductivity in excess of 0.04W / m.K. The floor portion may be free from insulation material, and so of material having thermal conductivity in excess of the above value. Materials which may be used in constructing the floor portion, and which may have thermal conductivities no less than about 0.04W / m.K, are detailed elsewhere in this document.

[0081] Further features of the method may be derived from the text set out elsewhere in this document, particularly in or with reference to any one or more of the first to fourth aspects of the invention.

[0082] According to a sixth aspect of the present invention, there is provided a building comprising: a first building section defining an internal volume; a modular building unit constructable to a substantially assembled form at a location which is distanced from a final location for the building, the modular building unit being transportable to the final location in the substantially assembled form and comprising: a floor portion comprising one or more material, the or each material forming the floor portion having a thermal conductivity of no less than about 0.04W / m.K; an internal volume containing a wet facility and defining a circulation space which provides at least one access function for the building during use, the access function optionally selected from the group comprising: access between upper and lower living spaces defined by the internal volume of the first building section; access between a first living space and at least one further living space defined by the internal volume of the first building section, the living spaces optionally provided in a same storey of the first building section; and access into the first building section from the outside of the building; in which the modular building unit is connected with the first building section at the final location to define at least part of the building.

[0083] The floor portion, in particular a floor portion support structure, may be of a material or materials having a thermal conductivity of no less than about 0.04W / m.K, optionally in excess of 0.04W / m.K. The floor portion may be free from insulation material, and so of material having a thermal conductivity in excess of the above value. The floor portion may be arranged so that there is no insulation / insulation material disposed within a perimeter of the support structure.

[0084] Further features of the building may be derived from the text set out elsewhere in this document, particularly in or with reference to any one or more of the first to fifth aspects of the invention.

[0085] In a seventh aspect of the present invention, there is provided a building system for a building according to the sixth aspect, in which the modular building unit is constructed to the substantially assembled form at the distanced location, and configured, in use: to define the circulation space; and to be connected with the first building section to define said part of the building.

[0086] According to an eighth aspect of the present invention, there is provided a method of constructing a building comprising at least one modular building unit, the method comprising the steps of: constructing a foundation for the building; providing a modular building unit comprising an internal volume and a floor portion defining a floor area of said unit, the floor portion comprising a floor portion support structure, and optionally : arranging the internal volume so that it contains a wet facility; and / or arranging the internal volume so that it defines at least part of a circulation space which provides an access function for the building; and locating the modular building unit on the foundation; in which the step of constructing the foundation comprises providing the foundation with a thermal insulation layer configured to extend under substantially the entire floor area of the modular building unit, the foundation thermal insulation layer having a thermal resistance (Ri); in which the step of providing the modular building unit comprises providing the floor portion support structure with an aggregate thermal resistance (R2); in which a total thermal resistance (RT) is equal to the sum of the foundation thermal insulation layer thermal resistance and the floor portion support structure aggregate thermal resistance (RT = R1+R2); and in which the method comprises arranging the foundation so that its thermal insulation layer thermal resistance (Ri) is at least around 60% of the total thermal resistance (RT).

[0087] The thermal insulation of the foundation may thermally insulate the modular building unit relative to ground on or in which the foundation is positioned.

[0088] In the method of this aspect, the provision of a foundation comprising an insulation layer having a thermal resistance (Ri) which is at least around 60% of the total thermal resistance (RT) may provide the benefit that a majority (and potentially all) insulation material for insulating the floor portion of the modular building unit can be provided in or by the foundation. This may make it possible to reduce a depth of insulation provided in the modular building unit (particularly in a floor portion of the unit), and potentially to dispense with insulation altogether, with the advantages discussed elsewhere in this document (particularly reduction of a depth of the floor portion).

[0089] The step of providing the at least one modular building unit may comprise constructing said unit to a substantially constructed form at a location away from a final location for the building. The method may comprise transporting the modular building unit to the final location in the substantially constructed form (in which it may define or describe the internal volume).

[0090] It will be understood that the assessment of RT (and so Ri and R2) is taken in a direction of thermal energy transfer between the modular building unit floor portion and the foundation, and so generally in a direction perpendicular to a main plane of the foundation. Accordingly, the assessment is effectively only for an area of the foundation taken up by the modular building unit (i.e. an area of the foundation on or over which the modular unit sits). Any areas of the foundation on which the (or a) modular building unit does not sit are not included in the assessment, since there would be no thermal energy transfer between a modular building unit floor portion and such areas.

[0091] The step of locating the at least one modular building unit on the foundation may comprise locating said unit on an upper surface of the foundation. The upper surface may be provided by a load bearing structure of the foundation; by the thermal insulation layer of the foundation; or by a moisture barrier of the foundation. Foundation construction options include those discussed elsewhere in this document. The load bearing structure of the foundation may provide structural support for the modular building unit.

[0092] The step of constructing the foundation may comprise arranging the load bearing structure as a layer in the foundation. The load bearing structure layer may be separate from the thermal insulation layer. The method may comprise providing a single or homogenous foundation structure providing the load bearing structure and the thermal insulation layer. For example, a load bearing structure may be provided which is of or includes a material having inherently insulating characteristics, thereby forming the insulation layer. Optional such materials can include cementitious materials e.g. foamed concrete.

[0093] The method may comprise arranging the foundation so that the foundation insulation layer thermal resistance (Ri) is at least around 65%, optionally at least around 70%, optionally at least around 75%, optionally at least around 80%, optionally at least around 85%, optionally at least around 90%, optionally at least around 95%, and optionally up to around 99% of the total thermal resistance (RT). The floor portion support structure of the modular building unit may, in certain constructions, define a relatively small proportion of the total thermal resistance (RT), optionally less than or equal to around 1% (i.e. R2 may be less than or equal to around 1% of RT). Constructions providing such a small proportion of the total can include uninsulated metal frame support structures. Constructions providing higher proportions of the total can include timber frame (uninsulated or insulated) support structures, which may provide between perhaps around 15% to around 40% of the total thermal resistance (RT).

[0094] As is well understood in the construction industry, the R-value of a building structural feature is its thermal resistance in SI units of m2.K / W, and is equal to the thickness t of the feature in the direction of heat transfer (measured in metres) divided by its thermal conductivity (measured in W / (m.K) ), i.e.:

[0095] References in this document to an R-value, and to thermal resistance, should be interpreted accordingly. It will be understood from this that a depth of the foundation insulation layer, and a thermal conductivity of material forming the layer, as well as a depth of the floor portion support structure and thermal conductivity of materials forming the structure, affect the associated R values (Ri andR2) and so the total R value (RT).

[0096] The thermal resistance of the foundation insulation layer may be its thermal resistance excluding e.g. any other materials, layers or structure of the foundation which do not have an insulating purpose (in particular a load bearing structure of the foundation). An exception to this could be where a load bearing structure of the foundation itself has an insulating capacity, e.g. where it is formed from a load bearing material which is relatively thermally insulative (such as foamed concrete). It is generally accepted in the construction industry that materials having thermal conductivities of no more than around 0.04W / m.K, and structural features having R values of no less than around 0.09m2.K / W, are generally considered to be thermally insulative.

[0097] Factors affecting a proportion of the total thermal resistance provided by the foundation thermal insulation layer can include: a depth of the foundation insulation layer; a thermal conductivity (A) of material forming the foundation insulation layer; a depth of the modular building unit floor portion support structure; the presence or absence of insulating material in e.g. void spaces of the modular building unit floor portion support structure, as well as the depth of such material; and thermal conductivity (A) of materials forming the modular building unit floor portion support structure.

[0098] In general terms, it may be desirable to provide a majority (optionally all) insulating material in the foundation.

[0099] It will be understood that this can have the result of the foundation thermal insulation layer thermal resistance (Ri) being in excess of 60% of the total thermal resistance (RT), optionally up to around perhaps 99% depending on factors including those discussed in the preceding paragraph.

[0100] One situation in which it may be desirable to provide insulation in the modular building unit floor portion support structure is when there is a cavity between an upper surface of a main part of the foundation and the floor portion of the modular building unit. This may occur for example where the floor portion is located on structural supports of or extending from the foundation. The cavity would typically be vented so that external air circulates within the cavity, which can lead to heat-loss from the floor portion to the cavity, and hence a need to insulate the floor portion. It will be understood though that thermal energy transfer to such an air cavity would be less than in the case of direct contact with e.g. a concrete foundation structure.

[0101] Reference is made to a floor portion support structure of the modular building unit. This should be taken to mean a structure of the modular building unit in or defining the floor portion of the unit, and which provides, in use, a load bearing function. It should not generally be taken to include any decorative layer or finishing material applied to, on or over the support structure, whose primary purpose is to provide a decorative (rather than structural) effect. This could include e.g. flooring materials such as tiles, wood or composite flooring and carpet, and associated support panels or backing structures. Reference to the floor portion itself should be understood to mean a portion of the modular building unit which forms, in use, a floor of the unit, i.e. a generally planar structure extending between (e.g. external) side walls and / or perimeter parts of the unit.

[0102] The method may comprise arranging the internal volume of the at least one modular building unit so that it forms at least one room. As described elsewhere in this document, said room may be arranged to provide or contain the wet facility, and so for example to define a bathroom, W / C or washroom, and / or an ensuite. The room may be closed or self-contained, may be defined by one or more wall, and may comprise a doorway or walkway opening.

[0103] The method may comprise arranging the foundation thermal insulation so that it extends under the entire floor area of the modular building unit. Where there are a plurality of modular building units located on the foundation, the method may comprise arranging the foundation thermal insulation layer so that it extends under the entire floor areas of each of said modular building units. Said modular building units may be located at a common level or storey in the building.

[0104] The method may be a method of constructing a hybrid building, or a method of constructing a modular building, as described elsewhere in this document.

[0105] The floor portion support structure aggregate thermal resistance R2 takes account of the thermal resistances of features and / or elements forming the support structure, and the fractional area of the support structure that they provide or accommodate (considered in the direction of heat / thermal energy transfer). The fractional area is assessed over a unit area (e.g. one square metre) of the support structure which sits on the foundation, and so above the foundation insulation layer. For example, the support structure may comprise a metallic frame having hollow metallic structural elements extending along a width direction of the modular building unit and connected to a perimeter frame. Each of the metallic structural elements comprises a closed internal air-filled void, and void spaces are defined between structural elements of the frame. The void spaces may be at least partly filled (and optionally substantially entirely filled) with an insulation material. The aggregate thermal resistance (R2) in this instance (assuming the void spaces are entirely filled with insulation material) is calculated using the following equation: where: Fa, / •), and Fcare the respective fractional areas (per m2) of the support structure accommodated by the metallic frame, the air void(s) and the insulation material in the void spaces; and Ra, Rb and Rcare the respective thermal resistances of the metallic material, air in the void(s), and the insulation material. The fractional areas are considered in the direction of heat transfer, and so in this case in a vertical plane (i.e. of a vertical crosssection).

[0106] As discussed above, the fractional areas are the proportions of the total area of the floor portion support structure accommodated by the various features / elements. So for example where the metallic structural elements accommodate 2.5% of the total area, the air filled voids 7.5% and the insulation in the void spaces 90% (per m2of floor area), the respective fractional areas are 0.025, 0.075 and 0.9.

[0107] It will be understood therefore that the aggregate thermal resistance of the features / elements forming the floor portion support structure includes any such voids and void spaces. It may however exclude other structural features of the modular building unit, for example wall support structures resting on and / or connected to the floor portion support structure. For the purpose of this analysis, the perimeter frame (e.g. perimeter frame members) may be excluded from the calculation, as they are considered to form a cold-bridge from walls of the modular unit, and assessed separately.

[0108] In the case where there are fewer or greater numbers of features / elements in the floor portion support structure to be accounted for, then the calculation is adjusted accordingly. In the case of there being only a single feature or element to account for (e.g. if the module floor portion support structure is formed as a single and / or homogenous structure), then the total thermal resistance R2 would simply be the thermal resistance of that feature.

[0109] The access function may be selected from the group comprising: access between upper and lower living spaces of the first building section; access between a first living space and at least one further living space of the first building section, said living spaces optionally being isolated from one another within the first building section and optionally on a same level / storey of the section; and access into the first building section from the outside of the building, and so access into the building from its exterior. Further details are set out elsewhere in this document. The method may comprise arranging the floor portion support structure so that it has a depth of no more than around 0.16m, optionally no more than around 0.15m, optionally no more than around 0.1m, optionally no more than around 0.07m, and optionally no more than around 0.05m. A depth in the range of about 0.05m to about 0.07m, optionally of around 0.05m, may be particularly beneficial, providing advantages including those discussed elsewhere in this document.

[0110] The method may comprise forming the insulation layer of the foundation from a material having a thermal conductivity (A) of no more than about 0.04W / m.K, and optionally of materials having a thermal conductivity in the range of about 0.038 to about 0.04W / m.K. Materials having such a thermal conductivity may have sufficient insulating characteristics for insulating the modular building unit relative to the ground, whilst also having the capacity to support structural loads imparted on the foundation during use. Suitable materials can include Isoquick® insulation which is of a water-resistant polymeric foam material (in particular Peripor®, as described elsewhere in this document), and extruded polystyrene foams (XPS).

[0111] According to a ninth aspect of the present invention, there is provided a building comprising: a foundation comprising a thermal insulation layer; and a modular building unit located on the foundation, the modular building unit comprising an internal volume and a floor portion defining a floor area of said unit, the floor portion comprising a floor portion support structure, and the modular building unit optionally being arranged: so that the internal volume contains a wet facility; and / or so that the internal volume defines at least part of a circulation space which provides an access function for the building; in which the foundation thermal insulation layer extends under substantially the entire floor area of the modular building unit and has a thermal resistance (Ri); in which the floor portion support structure of the modular building unit has an aggregate thermal resistance (R2); in which a total thermal resistance (RT) is equal to the sum of the foundation thermal insulation layer thermal resistance and the floor portion support structure aggregate thermal resistance (RT = R1+R2); and in which the foundation thermal insulation layer thermal resistance (Ri) is at least around 60% of the total thermal resistance (RT).

[0112] According to a tenth aspect of the present invention, there is provided a building system comprising: a foundation comprising a thermal insulation layer; and a modular building unit configured to be located on the foundation, the modular building unit comprising an internal volume and a floor portion defining a floor area of said unit, the floor portion comprising a floor portion support structure, and the modular building unit optionally being arranged: so that the internal volume contains a wet facility; and / or so that the internal volume defines at least part of a circulation space which provides, in use, an access function for the building; in which the foundation thermal insulation layer is configured, in use, to extend under substantially the entire floor area of the modular building unit and has a thermal resistance (Ri); in which the floor portion support structure of the modular building unit has an aggregate thermal resistance (R2); in which a total thermal resistance (RT) is equal to the sum of the foundation thermal insulation layer thermal resistance and the floor portion support structure aggregate thermal resistance (RT = R1+R2); and in which the foundation thermal insulation layer thermal resistance (Ri) is at least around 60% of the total thermal resistance (RT).

[0113] Optional further features of the building / system are as follows.

[0114] The at least one modular building unit may be manufactured to a substantially constructed form at a location away from a final location for the building. The modular building unit may be transportable to the final location in the substantially constructed form (in which it may define or describe the internal volume).

[0115] The at least one modular building unit may be locatable on an upper surface of the foundation. The upper surface may be provided by a load bearing structure of the foundation; by the thermal insulation layer of the foundation; or by a moisture barrier of the foundation. The load bearing structure of the foundation may provide structural support for the modular building unit.

[0116] The load bearing structure may be a layer in the foundation. The load bearing structure layer may be separate from the thermal insulation layer. The foundation may comprise a single or homogenous foundation structure comprising the load bearing structure and the thermal insulation layer. For example, a load bearing structure may be of or may comprise a material having inherently insulating characteristics, thereby forming the insulation layer.

[0117] The foundation insulation layer thermal resistance (Ri) may at least around 65%, optionally at least around 70%, optionally at least around 75%, optionally at least around 80%, optionally at least around 85%, optionally at least around 90%, optionally at least around 95%, and optionally up to around 99% of the total thermal resistance (RT). The floor portion support structure of the modular building unit may, in certain constructions, define a relatively small proportion of the total thermal resistance (RT), optionally less than or equal to around 1%.

[0118] The internal volume of the at least one modular building unit may be arranged so that, in use, it forms at least one room. Said room may be arranged to provide or contain the wet facility, and so for example to define a bathroom, W / C or washroom, and / or an ensuite.

[0119] The foundation thermal insulation may extend, in use, under the entire floor area of the modular building unit.

[0120] Where there are a plurality of modular building units located on the foundation, the foundation thermal insulation layer may extend, in use, under the entire floor areas of each of said modular building units. Said modular building units may be located at a common level or storey in the building.

[0121] The building may be a hybrid building, or a modular building, as described elsewhere in this document.

[0122] The access function may be selected from the group comprising: access between upper and lower living spaces of the first building section; access between a first living space and at least one further living space of the first building section, said living spaces optionally being isolated from one another within the first building section and optionally on a same level / storey of the section; and access into the first building section from the outside of the building, and so access into the building from its exterior. Further details are set out elsewhere in this document.

[0123] The floor portion support structure may have a depth of no more than around 0.16m, optionally no more than around 0.15m, optionally no more than around 0. Im, optionally no more than around 0.07m, and optionally no more than around 0.05m. A depth in the range of about 0.05m to about 0.07m, optionally of around 0.05m, may be particularly beneficial, providing advantages including those discussed elsewhere in this document.

[0124] The invention may also provide a modular building unit forming part of a building according to the ninth aspect, or a building system according to the tenth aspect, the modular building unit configured to be located on the building foundation, in which the floor portion support structure of the modular building unit is arranged so that its thermal resistance (R2) is no more than around 40% of the total thermal resistance (RT).

[0125] The foundation thermal insulation layer may be of or may comprise a material or materials having a thermal conductivity (A) of no more than about 0.04W / m.K, optionally in the range of about 0.038 to about 0.04W / m.K.

[0126] Further features of the modular building unit may be derived from the text set out elsewhere in this document, particularly in or with reference to any one of the eighth to tenth aspects.

[0127] According to an eleventh aspect of the present invention, there is provided a modular building unit configured to form part of a building, the modular building unit comprising: an internal volume which optionally contains a wet facility, and / or which optionally defines at least part of a circulation space providing an access function for the building; and a floor portion comprising a support structure having an aggregate thermal resistance (R) which is no more than around 3.25 m2.K / W.

[0128] The modular building unit floor portion support structure may be a frame support structure. The frame support structure may comprise a metallic frame having metallic structural elements, which may be hollow elements and may each comprise a closed internal air-filled void. The frame support structure may comprise timber (or wood-based) structural elements, which may have a substantially solid cross-section. Void spaces may be defined between structural elements of the frame structure. The void spaces may be at least partly filled (and optionally substantially entirely filled) with an insulation material. The aggregate thermal resistance (R) may take account of the thermal resistances of features and / or elements forming the support structure and the fractional area of the support structure that they provide or accommodate (considered in the direction of heat / thermal energy transfer). This will be understood to include any such voids and void spaces.

[0129] Insulation provided in the void spaces may have a thermal conductivity (A) of no more than about 0.04W / m.K, optionally in the range of about 0.038 to about 0.04W / m.K.

[0130] The floor portion support structure may have a depth of no more than around 0.16m, optionally no more than around 0.15m, optionally no more than around 0. Im, optionally no more than around 0.07m, and optionally no more than around 0.05m. A depth in the range of about 0.05m to about 0.07m, optionally of around 0.05m, may be particularly beneficial, providing advantages including those discussed elsewhere in this document.

[0131] Aggregate thermal resistances of no more than around 3.25m2.K / W can be achieved employing for example a timber frame support structure for the modular building unit floor portion, with a depth of up to around 0.16m, and employing insulating material in (and substantially filling) the void spaces having a thermal conductivity (A) of no more than about 0.04W / m.K. Support structures having such a thermal resistance may provide up to around 40% of a total thermal resistance which is the sum of the floor portion support structure aggregate thermal resistance and a thermal resistance of an insulating layer of a foundation, of the type described elsewhere in this document. Floor portion support structure constructions providing higher proportions of the total can include timber frame (uninsulated or insulated), which may provide between perhaps around 15% to around 40% of the total thermal resistance (RT). Reducing the support structure depth to around 0.05m in the above example may reduce the thermal resistance to around lm2.K / W.

[0132] Aggregate thermal resistances can be significantly lower where a metallic frame support structure is employed, e.g. of the type described above. Floor portion support structure aggregate thermal resistances of no more than around 0.037m2.K / W can be achieved employing for example a metallic frame having hollow metallic structural elements each comprising a closed internal air-filled void, having a depth of up to around 0.05m, without insulating material in the void spaces (optionally for use with foundation layer insulation having a thermal conductivity (A) of no more than about 0.04W / m.K). Increasing the depth to around 0.16m may increase the thermal resistance to around 0.194m2. K / W.

[0133] In both cases, the aggregate thermal resistance may be reduced if no insulation is provided in the void spaces, if a depth of insulation in the void spaces is reduced, and / or if a material having a higher thermal conductivity (i.e. a poorer performing insulation) is used in the void spaces.

[0134] The modular building unit may be configured to be located on a foundation of a building according to the ninth or tenth aspect of the invention. Further features of the modular building unit may be derived from the text set out elsewhere in this document, including in or in relation to the ninth or tenth aspect. Further features of one or more of the aspects of the invention discussed above may be derived from the text set out elsewhere in this document, particularly in or in relation to any one or more other aspect disclosed herein. In particular, the internal volume may be configured to form at least one room as described elsewhere in this document.

[0135] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0136] Fig. 1 is a perspective view of a building, comprising a modular building unit, in accordance with an embodiment of the invention;

[0137] Fig. 2 is a simplified perspective view of the building shown in Fig. 1;

[0138] Figs. 3 and 4 are cross-sectional plan views respectively of lower and upper storeys of the building shown in Fig. 1, illustrating certain features of the building;

[0139] Figs. 5 and 6 are views corresponding to Figs. 3 and 4 respectively, illustrating certain further features of the building;

[0140] Fig. 7 is an isometric view of part of the building shown in Fig. 1, taken from a different angle, and illustrating a foundation of the building, according to an embodiment of the invention;

[0141] Fig. 8 is an enlarged cross-sectional view of the building shown in Fig. 7, taken in the direction of the arrow A- A;

[0142] Figs. 9 and 10 are isometric views of the building shown in Fig. 1, with parts of its structure removed, for ease of understanding;

[0143] Fig. 11 is a isometric view of part of a building in accordance with an alternative embodiment of the present invention, and comprising an alternative foundation;

[0144] Fig. 12 is an enlarged cross-sectional view of the building shown in Fig. 11, taken in the direction of the arrow B-B;

[0145] Fig. 13 is a wire -frame perspective view part of a building in accordance with another embodiment of the invention;

[0146] Fig. 14 is a simplified isometric view of part of a building, comprising a modular building unit, in accordance with another embodiment of the invention; Fig. 15 is a vertical cross-section of a one-metre wide section of a floor portion support structure of the modular building units shown in Figs. 8 and 12, viewing along floor joists of the structure;

[0147] Fig. 16 is a table showing dimensions and fractional areas for floor portion support structural options which can form the floor portion support structures;

[0148] Fig. 17 is identical to Fig. 16, save that it presents an option in which insulation is contained within void spaces of the support structure;

[0149] Fig. 18 lists thermal conductivities (A), thickness (t) and R values of features detailed in the tables of Figs. 16 and 17;

[0150] Fig. 19 to 22 are tables detailing the proportions of the total thermal resistance RT provided by the modular unit floor portion support structure, and by the foundation insulation layer, for structural options set out in Figs. 16 and 17;

[0151] Figs. 23 to 26 are tables which correspond respectively to those of Figs. 19 to 22, save that they apply to the embodiment of Fig. 12, and show R values for different insulation material in the foundation;

[0152] Figs. 27 and 28 are tables similar to Figs. 16 and 17, respectively, showing dimensions and fractional areas for floor portion support structural options having a greater depth;

[0153] Fig. 29 lists thermal conductivities (A), thickness (t) and R values of features detailed in the tables of Figs. 27 and 28; and

[0154] Figs. 30 to 33 are tables corresponding to Figs. 23 to 26, for the structural options set out in Figs. 27 and 28.

[0155] The present invention generally concerns an insulated foundation for a building, the building comprising a modular building unit. The modular building unit is located on the foundation. A load bearing structure of the foundation can provide structural support for the modular building unit. Thermal insulation of the foundation can thermally insulate the modular building unit relative to the ground. The modular building unit has an internal volume which can contain a wet facility, and which can provide an access function for the building.

[0156] The present invention also generally concerns a modular building unit. The building can be a hybrid or modular building of the type disclosed in the applicant’s prior International patent publication nos.WO2022 / 243696, WO2022 / 243695, WO2022 / 243694, WO2022 / 243693 and WO2023 / 222853 (the disclosures of which are incorporated herein by this reference), or could be a fully modular building. In order to fully understand the features of the present invention, and how they apply to buildings of these different types, it is necessary firstly to discuss the structure of such a hybrid building. Turning therefore to Figs. 1 and 2, there are shown perspective and simplified perspective views, respectively, of a building 10 comprising a modular building unit 12a, in accordance with an embodiment of the invention. The building 10 can be considered to be a modular or hybrid building, comprising a first building section 14 and a second building section 16 which comprises the modular building unit 12a. The first building section 14 and the second building section 16 comprising the modular building unit 12a are connected together to form at least part of the building. In the illustrated embodiment, the building 10 takes the form of a modular or hybrid building of the general type disclosed in the applicant’s International patent publications identified above. The building 10 is a static residential building or domestic dwelling, in particular a detached house. The building 10 may, however, be a ‘fully modular’ structure, comprising a plurality of modular building units which together form the building. This will be discussed in more detail below. The invention also encompasses a modular building system which is used to form the building 10. The features of the building system will be evident from the following discussion.

[0157] General features of the building 10 are as follows. The first building section 14 is, in the illustrated embodiment, an on-site construction at a final, fixed, on-site location for the building 10. The first building section can take the form of a dock, to which the second building section 16 comprising the modular building unit 12a may be docked, installed, connected, or attached. The final, fixed, on-site location may be determined by construction plans and fixed by virtue of building foundations. The term “on-site location” is used to refer to the building site, which will be understood to refer to the immediate proximity of the building 10 and the entire building site, including a housing estate, on which the building is to be built. It will be understood that the site may be a large building / construction site comprising a plurality of plots, the final location for the building 10 being provided by one of said plots. The second building section 16 comprising the modular building unit 12a can take the form of a module which is dockable, installable, connectable, or attachable to another building section, particularly to a first building section in the form of a dock.

[0158] In the illustrated embodiment, the first building section 14 is configured to receive the second building section 16 comprising the modular building unit 12a. The modular building unit 12a is connected to and received by the first building section 14 at the final location of the building 10, to provide the building at the final, fixed, onsite location. During construction of the first building section 14 at the on-site location, the first building section is preconfigured to receive the second building section 16. That is, the first building section 14 is constructed with the knowledge and design that a second building section 16 is to be subsequently connected, and the first building section is thus preconfigured for connection and receipt of the second building section. This could relate to the shaping of the first building section 14, through to sealing and connection features. In a variation, the second building section 16 comprising the modular building unit 12a may be transported to the final location and positioned on site, and the first building section 14 subsequently constructed and connected to the modular building unit. The second building section 16 (comprising the modular building unit 12a) may however be enclosed or enveloped by the first building section 14, or otherwise positioned within a structure of the building provided by the first building section. The modular building unit 12a is transportable to the final location in a substantially assembled form. This may be taken to mean that the unit 12a is constructed to a state in which: it can be transported safely (i.e. it has sufficient structural integrity / rigidity for transport purposes); minimal further work is required to be carried out on the modular unit in order to connect it to the first building section 14; and / or minimal (optionally no) further work is required to complete a portion of the building formed by the modular unit. Such further work may be of a structural and / or weatherproofing nature, and may exclude work associated with a final fit-out of said unit, for example of a decorative nature (in particular the application of ‘perishable’ materials such as plaster / plasterboard, decorative panels and surface finishes such as paint).

[0159] The first building section 14 can be configured to receive the modular building unit 12 a, so that the first 14 and second 16 building sections may be connected. The first building section 14 and the second building section 16 may be provided with male-female structures, for facilitating the connection, or guiding the connection. This might also facilitate an at least partial sealing of or between the first and second building sections. In another example, the second building section 16 might closely abut against the first building section, and there may be no male -female structures. This might also facilitate an at least partial sealing of or between the building sections 14, 16.

[0160] Figs. 3 and 4 will now be referred to, which are more detailed cross-sectional plan views respectively of lower and upper storeys of the building 10 shown in Fig. 1, illustrating certain further features of the building.

[0161] The first building section 14 can be of any suitable construction, including but not limited to: a blockwork / masonry construction e.g. of clay bricks and / or cement blocks; a timber frame and blockwork / masonry construction; a timber frame and cladding construction; a metal frame construction (optionally comprising panels coupled to the frame, which may be composite panels comprising insulation material); a structure comprising structural insulated panels (SIPs); a time-setting 3D printed construction e.g. of a cementitious material; and combinations thereof. Timber frame options include ‘stick-built’ and timber frame panels. The further building section 14 can be constructed from a kit of building materials (e.g. blocks, timber frame components, metal structural elements) provided at the building site, the internal volume of the section suitably being formed entirely on the site at the final location.

[0162] The building 10 in-fact comprises the modular building unit 12a, and a further modular building unit 12b which, in the illustrated embodiment, is stacked on top of the unit 12a (although it could be provided separately e.g. spaced from the unit 12a, or provided adjacent to the unit 12a, at the same or a different level of the building). The modular building units 12a and 12b are connected and together form the second building section 16. Stacking of the modular building units 12a and 12b typically occurs at the final location, which facilitates handling and transportation. The modular building units 12a and 12b are of like construction, and configured to connect with the first building section 14 to form the completed building 10. The modular building units 12a and 12b are stacked directly on top of one another (that is with the upper unit 12b resting on top of the lower unit 12a). Access between the units 12a, b can therefore be achieved directly, without having to pass into or through any part of the first building section 14. As explained in detail in the applicant’s International patent publications mentioned above, the modular building units 12a and 12b provide a number of functions in the completed hybrid / modular building 10. These include that the modular building unit 12a includes a stairway or staircase 18 which provides access and / or an access route between a lower storey 20 and an upper storey 22 of the first building section 14, as indicated by the arrow 23 in Figs. 2 to 4.

[0163] In addition, and referring to Fig. 3 showing the lower storey 20, the modular building unit 12a comprises a front or main doorway 24 into the building 10, which provides access and / or an access route (indicated by the arrow 26 in the drawing) between an exterior 28 of the building 10 and an interior of the building, in particular of the first building section 14.

[0164] Still further, and referring to Fig. 4 showing the upper storey 22, the modular building unit 12b provides access and / or an access route between individual rooms or areas within the first building section 14, including rooms / areas which are isolated from one-an other, and so which cannot be accessed solely from within the first building section. This is indicated by the arrow 29 in Fig. 4. Access in this instance is provided between a master bedroom 30 and further bedrooms 32 and 34 in the first building section 14.

[0165] Figs. 5 and 6 are views corresponding to Figs. 3 and 4, illustrating circulation spaces / zones (or transition spaces / zones) defined by the modular building units 12a and 12b, which provide the access / access routes specified above. Two such circulation spaces are shown cross-hatched in the drawings, and indicated by reference numerals 36 and 38. The circulation spaces 36 and 38 encompass and / or are provided by a hallway 40, the staircase 18 and a landing 42 (see Figs. 3 / 4). The hallway 40 and staircase 18 are provided in or by the lower modular building unit 12a, and the landing 42 by the upper modular building unit 12b stacked on the unit 12a. The upper modular building unit 12b includes a stairway aperture or opening 44 which communicates with the staircase 18, to facilitate movement between the building units 12a and 12b (and so between the lower and upper storeys 20 and 22 of the first building section 14).

[0166] As mentioned above, the modular building 10 comprises the second building section 16 (defined by the modular building units 12a and 12b), and the first building section 14 (which is typically an on-site construction).

[0167] Further discussion of features of the modular building units will mainly reference the modular building unit 12a. The modular building unit 12b is however of similar construction, and it will be understood that the discussion of the unit 12a may apply equally to the unit 12b.

[0168] The modular building unit 12a defines an internal volume 46, and is transportable to the final location for the building 10 in the substantially assembled form shown in the drawings. The first building section 14 is configured, in use, to define an internal volume 48 which provides a living space 50 within the building 10. The living space 50 defines various rooms and / or areas of the building 10. These include an open-plan room providing a kitchen area 52, dining area 54, living area 56 and leisure area 58 in the lower storey 20, and the bedrooms 30 to 34 in the upper storey 22. The living space 50 which is provided therefore includes a lower living space part in the lower storey 20, and an upper living space part in the upper storey 22.

[0169] The internal volume 46 of the modular building unit 12a communicates directly with the internal volume 48 of the first building section 14. The communication is such that it is possible to transit from the internal volume 46 or 48 of one of the modular building unit 12a and the first building section 14 directly into the internal volume of the other one of the modular building unit and first building section, without having to pass through a further unit or part of the building 10, or to the building exterior 28. This is similarly the case for the upper modular building unit 12b.

[0170] As can be seen particularly from Figs. 3 and 4, the modular building units 12a / b each entirely define a plurality of rooms within the building 10. Specifically, the lower modular building unit 12a defines the utility room 106, W / C or washroom 102 and the service module 108. The upper modular building unit 12b defines the bathroom 100 and the utility room 104. As can be seen therefore, a plurality of the rooms 100 to 108 contain a wet facility. The modular building units 12a / b comprise walls which define boundaries of the rooms 100 to 108. Taking the bathroom 100 in the upper modular building unit 12b as an example, the unit comprises an external wall 101 and internal walls 103, 105 and 107 which together define a boundary of the bathroom. A door 109 is mounted in a doorway defined by the wall 107 and closes the doorway. The doorway may be considered to be an aperture at the boundary. The door 109 mounted in the doorway may not be considered to form part of the boundary itself, but rather to be provided at the boundary to permit access into the bathroom 100.

[0171] As best shown in Fig. 1, the modular building units 12a / b are arranged to define at least part of a perimeter of the building, which may be an external perimeter. In particular, external walls 101 and 111 define said part of the perimeter. The walls 101 and 111 are arranged so that an external surface of the walls defines an external surface of the building, or can be clad or surfaced with an exterior surface finish / coating (e.g. panels, bricks slips, cementitious render).

[0172] Turning now to Fig. 7, there is shown an isometric view of part of the building 10, taken from a different angle, and illustrating a foundation 60 of the building, according to an embodiment of the invention.

[0173] The foundation 60 generally comprises a load bearing structure 62 and thermal insulation 64. The modular building unit 12a is located on the foundation 60 so that the load bearing structure 62 of the foundation provides structural support for the modular building unit, and so that the thermal insulation 64 of the foundation thermally insulates the modular building unit relative to the ground. This is best shown in the enlarged cross- sectional view of Fig. 8, taken in the direction of the arrow A-A of Fig. 7.

[0174] By thermally insulating the foundation 60, it is possible to reduce a depth of insulation provided in the modular building unit 12a (particularly in a floor portion 68 of the unit), and potentially to dispense with insulation altogether, in at least the floor portion. This may provide the added benefit that a depth of the floor portion 68 can be reduced, relative to prior modular building units, with consequential benefits in terms of material / cost savings, weight savings and design flexibility. A requirement to have a relatively deep floor portion in a conventional modular building unit (for accommodating insulation) can make it necessary to increase a total height dimension of the modular building unit, or to reduce an internal floor to ceiling dimension, both of which can restrict design choice, and can be aesthetically or spatially undesirable. In addition, a hybrid building 10 of the type described will typically require that a floor of the first building section 14 be formed following connection of the first and second building sections 14 and 16, for example by pouring a concrete screed in the first section. The screed defines the final floor level in the first building section 14, and will be made level with the floor in the second building section 16 (provided by the floor portion 68). Reducing a depth of the floor portion 68 therefore has a benefit in terms of reducing a required depth of the screed.

[0175] In the illustrated embodiment, the modular building unit 12a floor portion 68 is completely free from insulation / insulation material. Insulation for the modular building unit 12a is instead provided by the thermal insulation 64 of the foundation 60. The floor portion 68 defines a floor 70 of the unit 12a, and comprises a floor portion support structure 72. This is best shown in Figs. 9 and 10, which are isometric views of the building 10 with parts of its structure removed, for ease of understanding. Fig. 9 shows a basic perimeter structure of the modular building units 12a / b, whilst Fig. 10 shows additional detail, including of floor, ceiling and wall structures. It will be noted that the modular building units 12a / b (and indeed the building 10) shown in Figs. 9 and 10 have a slightly different appearance to what is shown in Figs. 1 to 8. The differences relate mainly to matters of aesthetic design choices or floor plans, and so the same reference numerals are used.

[0176] The floor portion support structure 72 describes a floor perimeter 74, and the modular building unit 12a is arranged so that there is no insulation / insulation material disposed within the perimeter. This contrasts with conventional modular building units, in which it is typically necessary to provide insulation / insulation material within a perimeter of a floor support structure portion, for example in apertures between members forming the support structure (such as members of a frame forming the portion). This can have the disadvantages discussed above.

[0177] Materials used in constructing the floor portion 68 (in particular its support structure 72) have a thermal conductivity of no less than about 0.04W / m.K, and typically have thermal conductivities significantly in excess of 0.04W / m.K. Suitable materials include: metallic materials (metals and metal alloys, particularly steel and aluminium); timber / wood materials; cementitious materials (e.g. concrete); resin materials (e.g. polymeric resins); composite materials (e.g. glass or other fibre based resinous composites); and combinations thereof. These may be used variously for forming structural elements (support columns, beams, floor panels etc.) as well as surfacing / finishing elements (e.g. such as decorative floor panels). Exemplary thermal conductivities of suitable materials, and of other insulation materials (provided for comparison), are detailed in the following table:

[0178] The modular building unit 12a comprises an overall support structure, indicated generally at 76 in the drawings. The support structure 76 is a frame-type structure, and comprises the floor portion support structure 72, a plurality of wall portion support structures 78a to d (four in the illustrated embodiment, where the unit 12a is generally quadrilateral shape in plan-view, particularly rectangular), and a ceiling portion support structure 80.

[0179] The support structure portions 72, 78a-d and 80 each take the general form of a frame. Suitable materials for forming the support structure can include metals / metal alloys, and wood / timber, as well as combinations of any of these. In a support structure of a metal / metal alloy material, options for forming the support structure include cold-forming (e.g. pressed, stamped or rolled, and which may form an LGSF structure), hot-forming (e.g. hot rolled), and combinations of these. Another option for the support structure 76 is forming it as a panelised structure, comprising for example structural insulated panels (SIPs), although these would not typically be employed for the floor portion, which need not be insulated, as discussed above.

[0180] It will be understood that at least some structural elements forming the various different support structure portions 72, 76a-d and 80 may be shared, and so that such structural elements effectively form parts of more than one of the support structure portions. For example, the floor portion support structure 72 comprises structural elements in the form of opposed side beams 82a / b, and opposed end beams 84a / b connected between the side beams. The end wall support structure 78a comprises a floor beam 84a (shared with the floor portion support structure 72), opposed side columns 86a / b and a ceiling beam 88. The side wall support structure 78b comprises a floor beam 82a (shared with the floor portion support structure 72), side column 86a (shared with the end wall support structure 78a) and an opposed end wall column 86c, and a ceiling beam 92a. The other end and side wall portion support structures are similar and again share structural elements, and will not be described in detail. The various beams and columns in the support structure 76 are typically of a hot-rolled steel material, which provides good load bearing performance and the ability to point load, but alternatives including an LGSF (line-loaded) structure, and combinations of the two, are possible. Fig. 10 shows further structural elements including: floor joists 94 of the floor portion support structure 72, which extend between the side beams 82a / b: ceiling joists 96 of the ceiling portion support structure 80, which extend between ceiling beams 92a / b of the side wall portion support structures 78b / d: and insulated wall cladding panels 98a / b.

[0181] Referring back to Fig. 9, the floor portion 68 can optionally include one or more support beam, which may be connected to one or more of the side and end beams 82a / b and 84a / b. For example, a support beam 93 (shown in broken outline) may extend between the end beams 84a, 84b. A support beam 95 (shown in broken outline) may extend between e.g. the side beam 82a, and the support beam 93.

[0182] The various beams forming the floor portion 68 can be arranged to transfer loads directly to the foundation 60, and may be arranged so that they are line -loaded, so as to more evenly distribute such loads across the foundation (in comparison e.g. to a point-loaded structure, such as a light gauge structure. In particular, each of the side and end beams 82a / b, 84a / b can be arranged in contact with the load bearing structure 62 of the foundation 60, to more evenly transfer loading from the modular building unit 12a to the foundation. This can most suitably be achieved by constructing the floor frame of e.g. a hot-formed metallic material as described above, loading imparted on the beams being distributed more evenly along their lengths than in a point loaded structure. Thus loads not only of the modular building unit 12a itself, but loads applied to it e.g. by the upper modular building unit 12b, can be transferred more evenly to the foundation load bearing structure 62. This can also apply to the support beams e.g. 93 and 95, which may similarly be of a hot-formed metallic material, and arranged in contact with the load bearing structure 62 of the foundation. The support beams 93 and 95 may further be arranged so that they are substantially aligned with structural features of or in the upper modular building unit 12b, in particular similar support beams in a floor portion 110 of the upper unit, and / or internal walls of the upper unit (which may transfer loads through the upper unit’s floor frame portion to the lower modular building unit 12a). Arranging the floor portion 68 in this way may have the advantage that a material forming the thermal insulation 64 can be less dense, and / or can have a lower compressive strength. This can be beneficial because, generally speaking, insulation materials which are more dense, and / or which have a higher compressive strength, tend to be more costly.

[0183] The modular building units 12a / b are both arranged to provide living space within the building 10. Referring back to Figs. 3 and 4, in the illustrated embodiment, living space provided by the modular building units 12a / b defines wet facilities for the building 10, in the form of a bathroom 100, a W / C or washroom 102, an ensuite 104 for the master bedroom 30, and a utility room 106 accessed from the kitchen area 52 (including e.g. a sink, washing machine etc.). The utility room 106 may be arranged to provide water supply to the kitchen area 52. Sewerage / wastewater connections (not shown) may also be provided in the modular building units 12a / b.

[0184] The living space can be arranged to define at least part of other areas or rooms, including at least part of a bedroom or kitchen. The modular building units 12a / b also define further space within the building, which may be non-living space, such as a technical area. In the illustrated embodiment, the unit 12a comprises a service module or unit 108, which includes technical components that provide a service function such as heating, ventilation, utilities supply etc.

[0185] A construction method for the building 10 comprises locating the first (lower) modular building unit 12a on the foundation 60, and locating the second (upper) modular building unit 12b on the lower unit so that the upper unit is supported by the lower unit. The upper modular building unit 12b is therefore indirectly supported by the load bearing structure 62 of the foundation 60. The units 12a / b are connected at the final location by stacking them as shown in the drawings, suitably in direct contact with each other, but optionally in indirect contact e.g. with a structural member or layer between the units (not shown). The foundation thermal insulation 64 effectively thermally insulates the upper unit 12b relative to the ground, due to its location on the lower unit 12a. This has the result that the upper unit 12b can also comprise a floor portion 110 (Fig. 7) which is free from insulation / insulation material.

[0186] The foundation 60, and its method of construction, will now be described in more detail. The foundation 60 shown in Figs. 7 and 8 is formed at a site defining a final location for the building, by firstly preparing the ground 66 (where the building 10 is to be constructed) for receiving the foundation. This typically involves excavating the ground 66 down to a stable geological formation (e.g. clay), forming a cavity or recess for the foundation so that it is positioned below ground level in the constructed building.

[0187] The ground 66 is levelled, and any other necessary preparatory work carried out. This can include laying a bed 112 of a porous material (e.g. compacted aggregate and / or sand), which helps both to provide a level surface, and a stable layer which can drain any groundwater from the region below the foundation 60 during use. The thermal insulation 64 is then positioned on the drainage bed 112. Numerous options for forming the thermal insulation 64 exist, including constructing it from a series of shaped blocks (not shown) of a suitable insulating material which can bear the load of the completed building 10. Examples include Isoquick® insulation blocks commercially available in the UK from Build Homes Better Ltd, which can be arranged to form an insulation raft or pad. The blocks are formed from a water-resistant polymeric foam material, in particular Peripor® available from BASF SE. The blocks forming the thermal insulation 64 are typically arranged in two interlocking layers 64a / b, with interlocking features (not shown) such as protrusions and recesses provided at an interface 65 between the layers.

[0188] The thermal insulation 64 provides a surface 114 on which the load bearing structure 62 can be positioned, and in the illustrated embodiment, provides a substantially continuous surface. The load bearing structure 62 is located on the surface 114 following positioning of the thermal insulation on or in the ground 66. The load bearing structure 62 is insulated relative to the ground by the thermal insulation 64, so that thermal energy transfer between the load bearing structure and the ground 66 is resisted. This in turn insulates the modular building unit 12a (located on the foundation 60) relative to the ground 66, reducing / preventing thermal bridging between the unit and the ground (in particular its support structure 76).

[0189] Numerous options exist for forming the load bearing structure 62. In the illustrated embodiment, a substantially continuous platform, raft or pad is formed which defines the load bearing structure 62. The pad is of a cementitious material, suitably concrete, and comprises integral structural reinforcing elements (not shown), such as a mesh or grid of reinforcing bars (‘rebar’). Another option comprises forming a plurality of separate support elements (not shown), which together form at least part of the load bearing structure. The support elements would be spaced apart and / or not physically connected (at least by material forming the foundation 60 itself), or may be positioned next to / adjacent one another. These support elements could take the form of blocks, pads, piers, piles, columns or the like, or elongate beams, and may similarly be of a cementitious material as described above. In other options, combinations of the above techniques may be employed. It will be understood from the above that the load bearing structure 62 is typically formed at the building site. In a variation however, support elements arranged to form the load bearing structure may be preformed away from a site forming the final building location, and the foundation assembled at the site e.g. by arranging the support elements in a predetermined configuration. This may apply particularly where the foundation is formed from separate pads etc.

[0190] The foundation 60 is also provided with a moisture barrier, which resists moisture ingress into the modular building unit 12a (and so the building 10) from the ground 66 on / in which the foundation is positioned. The moisture barrier takes the form of at least one barrier layer, which provides a continuous sheet extending across a surface of the load bearing structure 62 and / or the thermal insulation 64, and which can be an upper or lower surface.

[0191] Typically a plurality of barrier layers are provided. Any suitable arrangement of the barrier layers within the foundation 60 may be employed. In the illustrated embodiment, a lower barrier layer 116 is positioned below the thermal insulation 64 (and so on the aggregate bed 112), and / or an upper barrier layer 118 is positioned between the upper surface 114 of the thermal insulation and a lower surface 120 of the load bearing structure 62. It is known in the industry that certain types of insulation are provided with an external metallic (e.g.

[0192] Aluminium) film or skin, and that this can degrade concrete over time. As well as providing a moisture barrier, the upper barrier layer 118 acts to resist such degrading of the concrete forming the load bearing structure 62. An additional, top barrier layer 122 can be provided on an upper surface 124 of the load bearing structure 62 if desired, and a bottom barrier layer 126 can be provided between the ground 66 and the aggregate bed 112.

[0193] The moisture barriers may take any suitable form known in the field of the invention. Particularly suitable options may include: a moisture resistant sheet, which may be a substantially impermeable membrane e.g. of a polymeric material such as polyethylene, for example those available from British Polythene Limited under the Visqueen™ brand; and breathable water resistant membranes such as those available from DuPont de Nemours, Inc. under the Tyvek® brand.

[0194] A layer of cementitious screed is supplied on the upper surface 124 of the load bearing structure 62 (or the barrier layer 122 if present) in the region of the building formed by the first building section 14, the layer indicated in broken outline and by numeral 71. This forms a floor of the first building section 14, which is at a same level as that of the floor 70 in the modular building unit 12a. In this way, a change in floor levels between the first and second building sections is avoided.

[0195] Turning now to Fig. 1 1, there is shown a perspective view of part of a building 10' in accordance with an alternative embodiment of the present invention, comprising an alternative foundation 60'. Like components of the building 10' and the foundation 60' with the building 10 and foundation 60 shown in Figs. 1 to 10 share the same reference numerals with the addition of the suffix '. Only substantive differences will be described. The foundation 60' is also shown in the enlarged cross-sectional view of Fig. 12, which is taken in the direction of the arrow B-B in Fig. 11.

[0196] In this embodiment, the building 10' comprises a second building section 16' which is built-in to the structure, again comprising two stacked modular building units (only a lower such unit 12a' being shown in the drawing). The second building section 16', in particular its modular building units, are built-in as they are effectively encapsulated within a wall structure 127 of a first building section 14' of the building. The wall structure 127 comprises inner and outer wall skins 129 and 131 with a cavity between them. As explained in the applicant’s International patent publications mentioned above, the wall structure 127 can be assembled on site and the modular building unit 12a subsequently positioned within the wall structure (e.g. lowered or translated in), or the unit may be positioned prior to formation of the wall structure (which can be supported from the modular units). Other wall structures may also be employed, which need not necessarily have such inner and outer wall skins and cavity.

[0197] Construction of the foundation 60' generally involves positioning a load bearing structure 62' on or in the ground 66 at the site forming the final location for the building 10'. The load bearing structure 62' provides a substantially continuous surface 128 on which thermal insulation 64' can be positioned. The thermal insulation 64' is positioned on the surface 128 of the load bearing structure 62' following positioning of the load bearing structure on or in the ground 66. In this scenario, the thermal insulation 64' is required to have sufficient load bearing capacity to bear structural loads imparted upon it by the modular building unit 12a, and indeed by a remainder of the building 10.

[0198] It will be understood that various options exist for creating the load bearing structure 62', and indeed the structure 62 used in the ‘insulation first’ approach of Fig.7. In the illustrated embodiment, the ground 66 is excavated to a suitable depth, and a trench 130 is formed. The trench extends around a perimeter 132 of the building 10. Concrete is supplied into the trench 130 to form a footing strip 134, and support piers comprising mortar bonded courses of bricks or blocks 136 and 138 are positioned on the strip. In a variation, the trench 130 may extend to a greater depth than that shown and receive both the footing strip 130 and the block courses 136, 138 (which may be secured by pouring additional concrete into the trench to bond and encapsulate the blocks).

[0199] An additional pier 142 of bricks / blocks extends between opposed ends 144, 146 of the foundation 60', and provides structural support to a portion of the module 12a located above it. A location of the block pier 142 in the foundation is indicated with a broken line in Fig. 11. A layer 140 of aggregate and / or sand is supplied within an internal perimeter (not shown) of the foundation 60' described by the piers formed by the blocks 136, 138. A barrier layer 1 16' e.g. of a suitable membrane is positioned on the aggregate layer 140, and a layer 141 of concrete supplied on to the barrier layer, to help secure the block courses 136 / 138.

[0200] The upper course of blocks 136 protrudes above the concrete layer 141, and provide surfaces 148 on which an upper layer of the load bearing structure 62' is positioned. Specifically, a further support layer 150 is formed from an arrangement of pre-cast beams 152 and blocks 154, as best shown in Fig. 11. The beams 152 are mostly of a generally inverted T-shape in cross- section, although those at the foundation ends 144, 146 are generally L-shaped. The beams 152 extend in a direction across the foundation between opposed sides 145, 147 and are spaced apart to define channels 156 which receive the blocks 154, the blocks being supported by lip portions of the inverted T or L-shaped beams. This arrangement of beams 152 and blocks 154 together forms a platform defining the surface 128 on which the thermal insulation 64' can be located. A void 143 is defined between the concrete layer 141 and the arrangement of beams 152 and blocks 154, and is usually ventilated (i.e. open to external air such as via an air vent) to prevent moisture build-up in the void. As will be described in more detail below, the presence of the void 143 (and its ventilation) will typically have the result that a floor portion of the modular building unit 12a’ will need to contain at least some insulation.

[0201] As shown in Fig. 1 1, the thermal insulation 64' extends across substantially the entire surface 128 to provide a thermal barrier between the module 12a located on the insulation and the ground 66. This helps to restrict a thermal bridge occurring between the load bearing structure 62' along the footing strip 134, brick courses 136 / 138, beam and block layer 152 / 154 and into the module support structure 76' (in particular its floor portion support structure 78'). A layer 71 ' of screed again forms a floor of the first building section 14'.

[0202] It will be understood from the above that the insulation layer 64' is required to bear structural loads of the building 10', and so must be of a material having sufficient structural integrity to bear the anticipated loads. Suitable materials include polymers such as expanded polystyrene insulation (EPS), available from many suppliers for example in panel form. It is known that insulation materials having greater structural load bearing capacity can have thermal conductivities (and U-values) which are higher than those having lower load bearing capacity. It may therefore be desirable to provide insulation materials having different characteristics within the portion of the foundation 60' which supports the first building section screed 71 ', compared to that which supports the second building section 16' (defined by the modules 12a / b). Insulation for the first section screed 71 ' may have a lower load bearing capacity and lower thermal conductivity (i.e. lower strength and greater thermal insulation performance) compared to that for the second section 16'.

[0203] Composite insulation structures (i.e. of different types) may be employed, particularly for the portion of the insulation layer 64' supporting the second building section 16'. High strength support pads or the like (not shown) may be provided for supporting the module 12a (in particular its support structure 76', e.g. its floor portion support structure 72'). Voids between the pads may be filled with a different insulation having a lower load bearing capacity than the pads, but a lower thermal conductivity. The insulation in the voids may not be required to bear structural loading of the modular building units.

[0204] Turning now to Fig. 13, there is shown a perspective view of part of a building 10" in accordance with another embodiment of the present invention. Like components of the building 10" with the building 10 share the same reference numerals with the addition of the suffix ". Only substantive differences will be described.

[0205] In a similar fashion to the building 10' of Fig. 11, a second building section 16" of the building 10" is built-in, in particular stacked modular building units 12a" and 12b" of the second section. In this embodiment, the modular units 12a" and 12b" each form part of an internal wall or skin of the building 10", and an external wall or skin (not shown) is constructed around the units following connection of the second building section 16" with a first building section 14". The external skin could be of any suitable form including a panel-based system, e.g. insulated cladding panels, or a brick / block skin.

[0206] The building 10" also differs from the building 10 in that it comprises a roof structure 158 which is a single / common roof structure, overlying both the first and second building sections 14" and 16". The roof 158 ties the first building section 14" relative to the second section 16", to provide structural rigidity to the constructed building 10". The roof 158 is supported by and connected to both of the building sections 14", 16" but can be arranged to be supported by or from one of the building sections and arranged to extend over the other section. The roof 158 comprises a plurality of roof trusses, one of which is indicated by numeral 160. The roof trusses 160 are each supported by and connected to the building sections 14" and 16", and formed of any suitable material, including but not restricted to wood and wood-based products / composites, and cold-formed metal (e.g. LGSF). It will be understood that, in a roof constructed using roof trusses, the trusses are typically pre -formed and brought to the final location for installation.

[0207] Turning finally to Fig. 14, there is shown part of a building 10"' in accordance with another embodiment of the present invention. Like components of the building 10"' with the building 10 share the same reference numerals with the addition of the suffix '". Only substantive differences will be described.

[0208] In this embodiment, the building 10'" is fully modular, comprising a plurality of modular building units which together form an entire (or substantially an entire) internal volume of the building. Modular building units 12a"', 12b'", 12c and 12d are shown in simplified form in the drawing, and are arranged in a predetermined configuration to form the building, each unit being connected to adjacent units to form the structure. It will be understood that many different arrangements of modular building units are possible beyond that shown in the drawing, including single or more than two storey arrangements (which is true also of the hybrid buildings discussed above). A foundation 60'" is essentially the same as that shown in Figs. 7 / 8 and described above, and so comprises a load bearing structure 62'" and thermal insulation 64'" (plus a barrier layer or layers). Equally, whilst not shown, a foundation similar to that shown in Figs. 11 / 12 may be provided.

[0209] Further aspects and features of the invention will now be described, with reference again to Figs. 7 to 14.

[0210] A method of constructing a building comprising at least one modular building unit is disclosed, which can be any of the buildings 10 to 10"' discussed above. Reference will however be made primarily to the building 10. The constructed building, and a building system are also disclosed, having features which will be evident from the following discussion.

[0211] The method generally comprises the steps of constructing the foundation 60 for the building 10, and providing the modular building unit 12a, which comprises internal volume 46 and floor portion 68. The floor portion 68 defines a floor area of said unit (indicated in cross-hatching at 162 in Fig. 7), and comprises the support structure 72. As discussed above, the unit 12a also contains a wet facility and defines at least part of a circulation space which provides an access function for the building. The modular building unit 12a is located on the foundation 60, substantially as described above.

[0212] The step of constructing the foundation 60 comprises providing it with the thermal insulation layer 64, and arranging the layer so that it extends under substantially the entire floor area 162 of the modular building unit 12a, and in the illustrated embodiment, under the entire such area. This is indicated in cross-hatching at 164 in Fig. 7, which it will be understood is the area of the foundation 60 which the unit 12a accommodates when it is located on the foundation.

[0213] The foundation thermal insulation layer 64 has a thermal resistance Ri. The support structure 72 of the modular unit 12a floor portion 68 has an aggregate thermal resistance R2, which accounts for the various different structural features / elements in the support structure. A total thermal resistance RT is equal to the sum of the foundation thermal insulation layer 64 thermal resistance, and the floor portion support structure 72 aggregate thermal resistance, i.e. RT = R1+R2. The method comprises arranging the foundation 60 so that its thermal insulation layer 64 thermal resistance Ri is at least around 60% of the total thermal resistance RT.

[0214] This may provide the benefit that a majority (and potentially all) insulation material for insulating the floor portion 72 of the modular building unit 12a can be provided in or by the foundation 60. This may make it possible to reduce a depth of insulation provided in the modular building unit 12a (particularly in the floor portion 72), and potentially to dispense with insulation altogether, with the advantages discussed elsewhere in this document (particularly reduction of a depth of the floor portion).

[0215] It will be understood that the assessment of RT (and so Ri and R2) is taken in a direction of thermal energy transfer between the floor portion 78 and the foundation 60, and so generally in a direction perpendicular to a main plane of the foundation. Accordingly, the assessment is effectively only for the area 164 of the foundation taken up by the modular building unit 12a (i.e. the area of the foundation on or over which the modular unit sits). Areas of the foundation 60 on which no modular building units sit are not included in the assessment, since there would be no thermal energy transfer between a modular building unit floor portion and such areas.

[0216] As will be discussed in relation to examples below, the method can comprise arranging the foundation 60 so that its insulation layer 64 thermal resistance Ri is at least around 65%, optionally at least around 70%, optionally at least around 75%, optionally at least around 80%, optionally at least around 85%, optionally at least around 90%, optionally at least around 95%, and optionally up to around 99% of the total thermal resistance RT. The floor portion support structure 72 of the modular building unit 12a, in certain constructions, defines a relatively small proportion of the total thermal resistance RT, optionally less than or equal to around 1% (i.e. R2 may be less than or equal to around 1% of RT). Constructions providing such a small proportion of the total can include uninsulated metal frame support structures. Constructions providing higher proportions of the total can include timber frame (uninsulated or insulated) support structures, which may provide between perhaps around 15% to around 40% of the total thermal resistance RT. As is well understood in the construction industry, the R-value of a building structural feature is its thermal resistance in SI units of m2.K / W, and is equal to the thickness t of the feature in the direction of heat transfer (measured in metres) divided by its thermal conductivity (measured in W / (m.K) ), i.e.:

[0217] It will be understood from this that a depth of the foundation insulation layer 64, and a thermal conductivity of material forming the layer, as well as a depth of the floor portion support structure 72 and thermal conductivity of materials forming the structure, affect the associated R values (Ri and R2) and so the total R value (RT).

[0218] The thermal resistance of the foundation insulation layer 64 is its thermal resistance excluding e.g. any other materials, layers or structure of the foundation 60 which do not have an insulating purpose (in particular the load bearing structure 62 of the foundation). An exception to this could be where a load bearing structure of the foundation itself has an insulating capacity, e.g. where it is formed from a load bearing material which is relatively thermally insulative (such as foamed concrete). It is generally accepted in the construction industry that materials having thermal conductivities of no more than around 0.04W / m.K, and structural features having R values of no less than around 0.09m2.K / W, are generally considered to be thermally insulative.

[0219] Factors affecting a proportion of the total thermal resistance provided by the foundation thermal insulation layer 64 can include: a depth of the foundation insulation layer; a thermal conductivity (A) of material forming the foundation insulation layer; a depth of the modular building unit floor portion support structure 72; the presence or absence of insulating material in e.g. void spaces of the modular building unit floor portion support structure, as well as the depth of such material; and thermal conductivity (A) of materials forming the modular building unit floor portion support structure.

[0220] In general terms, it may be desirable to provide a majority (and potentially all) insulating material in the foundation 60. It will be understood that this can have the result of the foundation thermal insulation layer thermal resistance Ri being in excess of 60% of the total thermal resistance RT, optionally up to around perhaps 99% depending on factors including those discussed in the preceding paragraph.

[0221] One situation in which it may be desirable to provide insulation in the modular building unit floor portion support structure 72 is when there is a cavity between an upper surface of a main part of the foundation and the floor portion of the modular building unit. This may occur for example where the floor portion is located on structural supports of or extending from the foundation, which is the case in the embodiment of Figs. 1 1 and 12. The void space (or cavity) 143 will typically be vented so that external air circulates within the cavity, which can lead to heat-loss from the floor portion 72 to the cavity, and hence a need to insulate the floor portion. It will be understood though that thermal energy transfer to such an air cavity would be less than in the case of direct contact with e.g. a concrete foundation structure, as in the embodiment of Figs. 7 and 8.

[0222] In the context of at least this aspect of the invention, reference is made to a floor portion support structure 72 of the modular building unit 12a. This should be taken to mean a structure of the modular building unit 12a in or defining the floor portion 68 of the unit, and which provides, in use, a load bearing function. It should not generally be taken to include any decorative layer or finishing material applied to, on or over the support structure 72, whose primary purpose is to provide a decorative (rather than structural) effect. This could include e.g. flooring materials such as tiles, wood or composite flooring and carpet, and associated support panels or backing structures. Reference to the floor portion 68 itself should be understood to mean a portion of the modular building unit 12a which forms, in use, the floor 70 of the unit, i.e. a generally planar structure extending between (e.g. external) side walls 78a-d and / or parts of the perimeter 74 of the unit (Fig. 9).

[0223] As can be seen in Fig. 7, the foundation thermal insulation 64 extends under the entire floor area 162 of the modular building unit 12a (as indicated by the hatched area 164). In embodiments in which there are a plurality of modular building units located on the foundation (as in Fig. 14), the method comprises arranging the foundation thermal insulation layer 64 so that it extends under the entire floor areas of each of the modular building units that are located at a common level or storey in the building. In Fig. 14, this applies to the units 12a"' and 12c.

[0224] The floor portion support structure 72 aggregate thermal resistance R2 takes account of the thermal resistances of features and / or elements forming the support structure, and the fractional area of the support structure that they provide or accommodate (considered in the direction of heat / thermal energy transfer). The fractional area is assessed over a unit area (one square metre) of the support structure 72 which sits on the foundation 60, and so above the foundation insulation layer 64, and are of a vertical cross-section.

[0225] For example, in the exemplary embodiments of Figs. 8 and 12, the support structure 72 can comprise a metallic frame having hollow metallic structural elements (floor joists 94) extending across a width direction of the modular building unit and connected to a perimeter frame (defined by the beams 82a / b and 84a / b). The joists 94 may be disposed at approximately 600mm spacings, centre to centre. Reference is made to Fig. 15, which is a vertical cross-sectional view through of a one-metre wide portion of the support structure 72, viewing along the joists 94. It will be understood that the structure is the same along a one-metre length of the structure, hence providing the one metre square unit area mentioned above. Each of the metallic joists 94 takes the form of a hollow box section of 3mm wall thickness, and comprises a closed internal air-filled void 166. Void spaces 168 to 172 are defined between the joists which are filled with an insulation material.

[0226] The aggregate thermal resistance R2 of the support structure 72 in this instance is calculated using the following equation: where: Fa, / •), and Fcare the respective fractional areas (per m2) of the support structure accommodated by the metallic joists 94, the air voids 166 and the insulation material in the void spaces 168 to 172; and Ra, Rb and Rcare the respective thermal resistances of the metallic material, air in the voids, and the insulation material. As discussed above, the fractional areas are the proportions of the total area of the floor portion support structure accommodated by the various features / elements, in the vertical cross-section. So for example where the hollow metallic beams 94 accommodate 2.5% of the total area, the air filled voids 166 accommodate 7.5%, and the insulation in the void spaces 168 to 172 collectively accommodate 90% (per m2), the respective fractional areas are 0.025, 0.075 and 0.9.

[0227] It will be understood therefore that the aggregate thermal resistance of the features / elements forming the floor portion support structure 72 includes any such voids 166 and void spaces 168 to 172. This could include e.g. bracing members extending along a length direction of the structure, generally perpendicular to the joists 94 which extend along the width direction. It may however exclude other structural features of the modular building unit, for example the wall support structures 78a-d resting on and / or connected to the floor portion support structure. For the purpose of this analysis, the perimeter frame formed by the perimeter frame members 82a / b and 84a / b are excluded from the calculation, as they are considered to form a cold-bridge from walls of the modular unit 12a, and assessed separately.

[0228] In the case where there are fewer or greater numbers of features / elements in the floor portion support structure 72 to be accounted for, then the calculation is adjusted accordingly. In the case of there being only a single feature or element to account for (e.g. if the module floor portion support structure 72 were formed as single and / or homogenous structure), then the total thermal resistance R2 would simply be the thermal resistance of that feature.

[0229] Exemplary calculations for embodiments of the invention, and for a range of different modular unit floor depths and insulation material, will now be described.

[0230] Reference is made firstly to Fig. 16, which is a table showing dimensions and fractional areas for floor portion support structural options which can form the floor portion support structures 72 or 72’ shown in Figs. 8 and 12. The first column lists optional parts of the support structures. The second column lists the total cross-sectional areas for the parts of the structure in the first column, in the vertical cross-section of Fig. 15. The third column lists the area of each part in the structure. The fourth column lists the number of structural features in the Im wide section shown in Fig. 15 (in this case the floor joists 94). The fifth column lists the fractional area (of the vertical cross-section) that the parts of the structure listed in the first column accommodate, as a proportion of the total.

[0231] Fig. 16 presents options in which no insulation is contained within the void spaces 168 to 172. It will be noted there are two structural features (joists 94) in the Im wide section, hence the total area taken up by the joists (‘structure 50x50mm’ shown in the third row) is 2500mm2multiplied by the number of features, i.e. 5000mm2. The fifth row details the wall thickness of the steel joists 94 which define the total structure area of 5000mm2, which as can be seen is 3mm. Hence an area accommodated by each hollow joist is 564mm2, giving a total of 1128mm2for the two. Similarly, the air voids 166 in the joists 94 (fourth row) accommodate a total area of 3872mm2, and the air in the void spaces 168 to 172 (sixth row) a total of 4500 mm2. The table shown in Fig. 17 is identical to Fig. 16, save that it presents an option in which insulation is contained within the void spaces 168 to 172. Hence the final row in the table lists the area accommodated by insulation, rather than the air in the void spaces as in the final row of Fig. 16.

[0232] The table shown in Fig. 18 lists, in the second to fourth columns respectively, the thermal conductivities (A), thickness (t) and R values of the features detailed in the tables of Figs. 16 and 17 (using the equation R=t / detailed above). Figures for further structural options applicable to the embodiment of Fig. 12 are detailed in rows six and seven (for the beams 152 and blocks 154), but do not form part of the calculations.

[0233] The table in Fig. 19 details the proportions of the total thermal resistance RT provided by the modular unit 12a floor portion support structure (‘mod’s floor structure - second row in the numbered section - i.e. Ri), and by the foundation insulation layer 4 (‘isoquick insulation’ - fourth row - i.e. R2), for an insulated hollow metallic frame support structure. In this example, insulation having the thermal conductivity and thickness detailed in the third row of Fig. 18 is present in the void spaces 168 to 172. The figure for R2is calculated using the equation detailed above, and takes account of the various features in the support structure. The calculation therefore employs the fractional areas and material R values detailed in Figs. 16 to 18. As can be seen, in this example the foundation thermal insulation layer thermal resistance Ri represents around 99% of the total thermal resistance RT.

[0234] The table in Fig. 20 is the same as for Fig. 19, save that there is no insulation in the void spaces 168 to 172. This makes little difference however over the relatively small depth metallic floor portion structure, the foundation thermal insulation layer thermal resistance (Ri) again representing around 99% of RT.

[0235] The table in Fig. 21 is the same as for Fig. 18, save that the hollow box section metal joists 94 have been replaced with solid cross-section joists of timber having the properties set out in the fourth row of Fig. 18. The much lower thermal conductivity of the timber (which is an exemplary timber that can be selected from a wide range of options) in comparison to the air-filled hollow metal joists makes a significant difference, increasing the proportion of RT provided by the floor portion support structure 72 (R2 here is around 13%). The foundation thermal insulation layer thermal resistance (Ri) therefore represents around 87% of RT.

[0236] The table in Fig. 22 is the same as for Fig. 20, save that there is no insulation in the void spaces 168 to 172. This makes a small difference, the foundation thermal insulation layer thermal resistance (Ri) representing around 89% of RT.

[0237] By way of reference, but not shown in table form, replacing the floor portion support structure with an insulative slab e.g. of Isoquick® insulation would provide figures for Ri and R2 of around 84% and 16% respectively. This would however present constructional challenges, for example in connection of wall support structures 78a-d to the slab. The tables in Figs. 23 to 26 correspond respectively to those of Figs. 19 to 22, save that they apply to the embodiment of Fig. 12, and show values for different insulation material in the foundation. It should be noted however that, despite the different foundation constructions of Fig. 12 in comparison to Fig. 8, this does not impact the Ri and R2 calculations (and so RT), as the comparison is between the floor portion support structure and the foundation insulation, and so discounts such foundation construction differences (‘beam and block’ at row three of the numbered areas in Figs. 23 to 26, versus ‘reinforced concrete’ in row three of Figs. 1 to 22). The different insulation used in these examples is XPS and has a higher thermal conductivity at 0.04W / m.K.

[0238] As explained above, values for Ri of at least around 60% are achievable, for example by increasing a depth of the floor portion support structure above the 50mm shown in Figs. 19 to 26. This will be briefly discussed, with reference to Figs. 27 to 33.

[0239] Fig. 27 is a table similar to Fig. 16, showing dimensions and fractional areas for floor portion support structural options at a depth of 160mm. As in Fig. 16, this applies to the support structures 72 and 72’. The table shown in Fig. 28 is identical to Fig. 27, save that it presents an option in which insulation is contained within the void spaces 168 to 172. The table shown in Fig. 29 lists, in the second to fourth columns respectively, the thermal conductivities (A), thickness (t) and R values of the features detailed in the tables of Figs. 27 and 28 (again using the equation R=t / ).

[0240] Figs. 30 to 33 correspond to Figs. 23 to 26 in terms of the constructional details of the floor portion support structure 72 / 72’ . As can be seen, values for Ri in the range of about 60% to about 95% can be achieved, depending upon the constructional details. A figure of 60% for Ri is achieved when timber joists are used for the floor portion support structure, and with insulation in the void spaces 168 to 172 (Fig. 32).

[0241] It will be understood that these examples apply to the embodiment of Fig. 12, and employ XPS insulation for the foundation insulation layer 64 as shown in the tables. As explained above however, these figures would apply equally to the embodiment of Fig. 8, due to the way in which the calculation is carried out. Small changes in the R value proportions can be obtained using different foundation insulation, e.g. Isoquick® discussed above. For example, Ri proportions of 96%, 97% 67% and 71% can be obtained, for the examples outlined in Figs. 30 to 33.

[0242] As can be seen from these examples, the construction method of the invention may comprise arranging the floor portion support structure 72 / 72’ so that it has a depth of no more than around 0. 16m. It may be preferred to limit the floor depth to be in the range of about 0.05m to about 0.07m, optionally no more than around 0.05m, which provides benefits those discussed elsewhere in this document. These include: general material / cost savings, weight savings, design flexibility and general reduction in complexity of the module and overall building construction.

[0243] As can be seen from the above example, the provision of a modular building unit comprising a floor portion having a support structure with an aggregate thermal resistance (R) which is no more than around 3.25 m2.K / W can therefore provide benefits, including an ability to reduce the floor depth of the unit. This is in contrast for example to prior modular building units with significantly deeper floor portions (e.g. around 300mm), containing large volumes of insulation material. Even then, problems with cold bridging to foundation structures have been encountered, which can be overcome by following the construction principles disclosed in this document. Such floor portion R values are attainable by limiting the material choices and floor depths to those disclosed in the examples, the 3.25 m2.K / W figure being shown in the example of Fig. 32 (floor support structure 72 / 72’ of 160mm depth, comprising solid timber joists at 600mm centre spacings, and with insulation having a thermal conductivity of 0.04W / m.K in the void spaces). In this example, R2 is around 40% of RT.

[0244] It will be noted that floor portion support structure aggregate thermal resistances can be significantly lower where a metallic frame support structure is employed, e.g. of the type described above. Per Fig. 24, floor portion support structure aggregate thermal resistances of no more than around 0.037m2.K / W can be achieved employing for example a metallic frame having hollow metallic structural elements each comprising a closed internal air-filled void, having a depth of around 0.05m, without insulating material in the void spaces, and with foundation layer insulation having a thermal conductivity (A) of no more than about 0.04W / m.K. Increasing the depth to around 0.16m in this example may increase the thermal resistance to around 0.194m2.K / W (Fig. 31).

[0245] Various modifications may be made to the foregoing without departing from the spirit or scope of the present invention.

[0246] For example, the method may comprise providing a plurality of modular building units, which may be configured to be fitted or coupled together (but could be spaced apart and / or out of contact).

[0247] Where there are a plurality of modular building units: only one (or only some) of the units may comprise a wet facility; and / or only one (or only some) of the units may define a circulation space, or at least part of a circulation space. This may apply particularly where the method involves constructing a modular building from a plurality of modular building units. At least one, and suitably a plurality, of the modular building units may define living space.

[0248] Where the foundation load bearing structure comprises a plurality of support elements, the thermal insulation may be applied as a continuous (or at least substantially continuous) layer on the ground below the support elements, or extending over the support elements.

[0249] In a variation, the foundation load bearing structure may be provided in combination with, or may define, the thermal insulation. In other words, the load bearing structure and the thermal insulation may be combined into, or provided as, a single (i.e. unitary) product / feature. Thus a load bearing structure may be provided having sufficient insulative properties to provide the required thermal barrier, or alternatively thermal insulation may be provided having the required structural load bearing capacity. Suitable options may include constructing the foundation at least partly from load bearing heat insulating building blocks / members, such as those available from Marmox (UK) Ltd under the Thermoblock™ brand, and Creagh Concrete Products Ltd under the Spantherm™ brand.

[0250] It is also conceivable that the thermal insulation can be provided in combination with, or may define, a moisture barrier. In other words, the thermal insulation and the moisture barrier may be combined into or provided as a single (i.e. unitary) product / feature, for example by forming the thermal insulation of an inherently moisture resistant material. Generally speaking however, legislation requires that a specific e.g. barrier membrane be provided, and so the thermal insulation and moisture barrier will typically be separate.

[0251] The different parts of the foundation, i.e. the load bearing structure, thermal insulation and moisture barrier (where present) may be arranged in any suitable combination / configuration. For example, considered from the ground up, the foundation may comprise: thermal insulation, load bearing structure and moisture barrier; load bearing structure, thermal insulation and moisture barrier; moisture barrier, thermal insulation and load bearing structure; or thermal insulation, moisture barrier and load bearing structure. It will be understood however that the moisture barrier may comprise a plurality of layers as discussed above.

[0252] Further aspects and / or embodiments of the invention may combine the features of one or more aspect and / or embodiment disclosed in this document. Accordingly, such further aspects and / or embodiments may comprise one or more feature selected from one or more aspect or embodiment of the invention disclosed in this document.

[0253] Unless explicitly implied by context or stated in the document, the features of any method or process disclosed in this document need not necessarily be performed in the precise order set out in the relevant text and / or drawings. Accordingly, any method or process disclosed in this document may be capable of being performed in an order other than that specifically set out in the relevant text / drawings, if circumstances permit.

[0254] Features disclosed in this document (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Accordingly, features disclosed in this document may represent only one example of a generic series of equivalent or similar features.

Claims

CLAIMS1. A method of constructing a building comprising at least one modular building unit, the method comprising the steps of: constructing a foundation for the building, including providing the foundation with a load bearing structure and thermal insulation; providing at least one modular building unit comprising an internal volume defining at least one room, the internal volume containing a wet facility and defining at least part of a circulation space which provides an access function for the building; and locating the at least one modular building unit on the foundation so that the load bearing structure of the foundation provides structural support for the modular building unit, and so that the thermal insulation of the foundation thermally insulates the modular building unit relative to the ground.

2. A method as claimed in claim 1, comprising providing the at least one modular building unit with a floor portion which is free from insulation material.

3. A method as claimed in claim 2, comprising: arranging the floor portion so that it defines a floor of said unit, and providing the floor portion with a floor portion support structure describing a perimeter of the floor portion; and the method further comprises arranging said unit so that there is no insulation material disposed within the floor perimeter.

4. A method as claimed in any preceding claim, comprising providing the at least one modular building unit with a floor portion formed from material having a thermal conductivity of no less than about 0.04W / m.K5. A method as claimed in any preceding claim, in which the method is a method of constructing a hybrid building comprising a site constructed section and the at least one modular building unit, and in which the method further comprises: constructing a first building section at a final location for the building; at a location away from the final location, constructing the at least one modular building unit to a substantially assembled form; transporting the at least one modular building unit to the final location in the substantially assembled form; and connecting the first building section and said modular building unit to form the building, said modular building unit forming a second building section of the building.

6. A method as claimed in any preceding claim, comprising arranging a first portion of the foundation insulation so that it has at least one characteristic which is different from a corresponding characteristic of a further portion of the foundation insulation.

7. A method as claimed in claim 6, comprising providing the first portion of the foundation insulation with at least one of a lower load bearing capacity, and a lower thermal conductivity, compared to the further portion of the foundation insulation.

8. A method as claimed in either of claims 6 or 7, when dependent on claim 5, comprising arranging the first portion of the foundation insulation so that it supports a floor portion of the first building section, and arranging the second portion of the foundation insulation so that it supports the modular building unit, optionally a floor portion of the modular building unit.

9. A method as claimed in any preceding claim, comprising arranging the at least one modular building unit so that it provides at least some living space, the living space defining one or more wet facility selected from the group comprising: a bathroom, a W / C or washroom, and an ensuite.

10. A method as claimed in any one of claims 1 to 4, in which the method is a method of constructing a modular building comprising a plurality of modular building units which together form substantially an entire internal volume of the building.

11. A method as claimed in any preceding claim, comprising: providing a plurality of modular building units which are configured to be fitted together; locating a first one of said units on the foundation; and locating a second one of said units on the first unit so that the second unit is supported by the first unit, so that the second one of said units is indirectly supported by the load bearing structure of the foundation, and thermally insulated relative to the ground by the thermal insulation of the foundation.

12. A method as claimed in any preceding claim, comprising arranging the circulation space so that it provides one or more access function selected from the group comprising: access between upper and lower living spaces of the first building section; access between a first living space and at least one further living space of the first building section, said living spaces being isolated from one another within the first building section on a same level or storey of said section; and access into the first building section from the outside of the building, and so access into the building from its exterior.

13. A method as claimed in any preceding claim, in which the step of constructing the foundation comprises positioning the thermal insulation on the ground at a site forming a final location for the building, and then positioning the load bearing structure on the thermal insulation.

14. A method as claimed in any one of claims 1 to 12, in which the step of constructing the foundation comprises positioning the load bearing structure on the ground at a site forming a final location for the building, and then positioning the thermal insulation on the load bearing structure.

15. A method as claimed in any preceding claim, in which the step of constructing the foundation further comprises providing the foundation with a moisture barrier.

16. A method as claimed in claim 15, comprising providing at least one moisture barrier layer, and arranging said barrier layer so that it provides a continuous sheet extending across a surface of at least one of: the load bearing structure; and the thermal insulation.

17. A method as claimed in either of claims 15 or 16, comprising: providing a moisture barrier layer positioned below the lowermost one of the load bearing structure and the thermal insulation; and / or providing a moisture barrier layer positioned: a) between an upper surface of the lowermost one of the load bearing structure and the thermal insulation, and a lower surface of the uppermost one of the load bearing structure and the thermal insulation; and / or b) on an upper surface of the uppermost one of the load bearing structure and the thermal insulation.

18. A method as claimed in claim 1, in which the step of constructing the foundation further comprises providing a load bearing structure which defines the thermal insulation.

19. A method as claimed in claim 1, in which the step of constructing the foundation further comprises providing thermal insulation which defines a moisture barrier.

20. A method as claimed in any preceding claim, comprising arranging said modular building unit so that it comprises one or more wall defining a boundary of the at least one room, the at least one room containing the wet facility.

21. A method as claimed in any preceding claim, comprising arranging the at least one modular building unit so that it defines at least part of a perimeter of the building.

22. A building comprising: a foundation comprising a load bearing structure and thermal insulation; and at least one modular building unit comprising an internal volume defining at least one room, the internal volume containing a wet facility and defining at least part of a circulation space that provides an access function for the building; in which the at least one modular building unit is located on the foundation so that the load bearing structure provides structural support for the modular building unit, and so that the thermal insulation thermally insulates the modular building unit relative to the ground.

23. A building as claimed in claim 22, in which the at least one modular building unit has a floor portion which is free from insulation material.

24. A building as claimed in either of claims 22 or 23, in which the at least one modular building unit has a floor portion formed from material having a thermal conductivity of no less than about 0.04W / m.K25. A building system comprising: a foundation comprising a load bearing structure and thermal insulation for a building; and at least one modular building unit comprising an internal volume defining at least one room, the internal volume containing a wet facility and defining at least part of a circulation space that provides, in use, an access function for the building; in which the at least one modular building unit is configured to be located on the foundation so that, in use: the load bearing structure provides structural support for the modular building unit; and the thermal insulation thermally insulates the modular building unit relative to the ground.

26. A method of constructing a building comprising at least one modular building unit, the method comprising the steps of: constructing a foundation for the building; providing a modular building unit comprising an internal volume and a floor portion defining a floor area of said unit, the floor portion comprising a floor portion support structure, and: arranging the internal volume so that it contains a wet facility; arranging the internal volume so that it defines at least part of a circulation space which provides an access function for the building; and locating the modular building unit on the foundation; in which the step of constructing the foundation comprises providing the foundation with a thermal insulation layer configured to extend under substantially the entire floor area of the modular building unit, the foundation thermal insulation layer having a thermal resistance (Ri); in which the step of providing the modular building unit comprises providing the floor portion support structure with an aggregate thermal resistance (R2); in which a total thermal resistance (RT) is equal to the sum of the foundation thermal insulation layer thermal resistance and the floor portion support structure aggregate thermal resistance (RT = R1+R2); and in which the method comprises arranging the foundation so that its thermal insulation layer thermal resistance (Ri) is at least around 60% of the total thermal resistance (RT).

27. A method as claimed in claim 26, in which the method comprises arranging the foundation so that the foundation insulation layer thermal resistance (Ri) is up to around 99% of the total thermal resistance (RT).

28. A method as claimed in any preceding claim, comprising arranging the internal volume of the at least one modular building unit so that it forms at least one self-contained room defined by one or more wall and comprising a walkway opening, the room containing the wet facility, the wet facility selected from the group comprising a bathroom, a W / C or washroom, and an ensuite.

29. A method as claimed in any one of claims 26 to 28, comprising arranging the foundation thermal insulation so that it extends under substantially the entire floor area of the modular building unit.

30. A method as claimed in any one of claims 26 to 29, comprising: providing a first building section at a final location for the building, including arranging the first building section so that it defines an internal volume; and connecting the modular building unit with the first building section at the final location, to define at least part of the building.

31. A method as claimed in any one of claims 26 to 29, comprising locating a plurality of modular building units on the foundation, at least one of said units comprising the wet facility and at least part of the circulation space, and arranging the foundation thermal insulation layer so that it extends under the entire floor areas of each of said modular building units.

32. A method as claimed in claim 31 , in which the modular building units are located at a common level in the building.

33. A method as claimed in any preceding claim, in which the access function is selected from the group comprising: access between upper and lower living spaces of the first building section; access between a first living space and at least one further living space of the first building section, said living spaces being isolated from one another within the first building section on a same level of the section; and access into the first building section from the outside of the building, and so access into the building from its exterior.

34. A method as claimed in any one of claims 26 to 33, comprising arranging the floor portion support structure so that it has a depth of between around 0.05m and around 0.16m.

35. A method as claimed in any one of claims 26 to 34, comprising arranging a first portion of the foundation insulation so that it has at least one characteristic which is different from a corresponding characteristic of a further portion of the foundation insulation.

36. A method as claimed in claim 35, comprising providing the first portion of the foundation insulation with at least one of a lower load bearing capacity, and a lower thermal conductivity, compared to the further portion of the foundation insulation.

37. A building system comprising: a foundation comprising a thermal insulation layer; and a modular building unit configured to be located on the foundation, the modular building unit comprising an internal volume and a floor portion defining a floor area of said unit, the floor portion comprising a floor portion support structure, and the modular building unit being arranged: so that the internal volume contains a wet facility; andso that the internal volume defines at least part of a circulation space which provides, in use, an access function for the building; in which the foundation thermal insulation layer is configured, in use, to extend under substantially the entire floor area of the modular building unit and has a thermal resistance (Ri); in which the floor portion support structure of the modular building unit has an aggregate thermal resistance (R2); in which a total thermal resistance (RT) is equal to the sum of the foundation thermal insulation layer thermal resistance and the floor portion support structure aggregate thermal resistance (RT = R1+R2); and in which the foundation thermal insulation layer thermal resistance (Ri) is at least around 60% of the total thermal resistance (RT).

38. A building system as claimed in claim 37, in which the at least one modular building unit is manufactured to a substantially constructed form at a location away from a final location for the building, and is transportable to the final location in the substantially constructed form.

39. A building system as claimed in either of claims 37 or 38, comprising a first building section constructable at a final location for the building, the first building section defining an internal volume, and in which the modular building unit is connected with the first building section at the final location, to define at least part of the building.

40. A building system as claimed in any one of claims 37 to 39, in which the foundation insulation layer thermal resistance (Ri) provides up to around 99% of the total thermal resistance (RT).

41. A building system as claimed in any one of claims 37 to 40, in which the foundation thermal insulation extends, in use, under the entire floor area of the modular building unit.

42. A building system as claimed in claim 37, comprising a plurality of modular building units configured to be located on the foundation at a common level in the building, and in which the foundation thermal insulation layer extends, in use, under the entire floor areas of each of said modular building units.

43. A building system as claimed in any one of claims 37 to 41, in which the access function is selected from the group comprising: access between upper and lower living spaces of the first building section; access between a first living space and at least one further living space of the first building section, said living spaces being isolated from one another within the first building section and on a same level of the section; and access into the first building section from the outside of the building, and so access into the building from its exterior.

44. A building system as claimed in any one of claims 37 to 43, in which the floor portion support structure has a depth of between around 0.05m and around 0.16m.

45. A building comprising:a foundation comprising a thermal insulation layer; and a modular building unit located on the foundation, the modular building unit comprising an internal volume and a floor portion defining a floor area of said unit, the floor portion comprising a floor portion support structure, and the modular building unit being arranged: so that the internal volume contains a wet facility; and so that the internal volume defines at least part of a circulation space which provides an access function for the building; in which the foundation thermal insulation layer extends under substantially the entire floor area of the modular building unit and has a thermal resistance (Ri); in which the floor portion support structure of the modular building unit has an aggregate thermal resistance (R2); in which a total thermal resistance (RT) is equal to the sum of the foundation thermal insulation layer thermal resistance and the floor portion support structure aggregate thermal resistance (RT = R1+R2); and in which the foundation thermal insulation layer thermal resistance (Ri) is at least around 60% of the total thermal resistance (RT).

46. A building as claimed in claim 45, comprising a first building section constructed at a final location for the building, the first building section defining an internal volume, and in which the modular building unit is connected with the first building section at the final location, to define at least part of the building.

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