Building construction & method of assembly thereof

Abstract

In various embodiments, the present invention provides building constructions comprising a double frame wall structure comprising an inner frame structure and an outer frame structure, each of said inner frame structure and outer frame structure comprising a plurality of upstanding column members connected by horizontally-extending elements, the inner and outer frame structure being separate from one another and arranged in a spaced manner such that a cavity that extends about a perimeter of the building construction is defined between the inner and outer frame structures, wherein the cavity is filled with an insulation material to thereby provide a substantially continuous insulation envelope between the inner and outer frame structures. The present invention also provides methods of assembly of building constructions.

Description

[0001] Building Construction & Method of Assembly Thereof

[0002] This application claims priority from GB 2407546.7 filed 28 May 2024, the contents and elements of which are herein incorporated by reference for all purposes.

[0003] Field of the Invention

[0004] The present invention relates to a building construction, and method of assembly of such building construction. In particular, it relates to a building constructing employing a dual-skin arrangement to provide a substantially continuous external envelope for a building.

[0005] Background

[0006] Various forms of building construction are known in the art. Masonry is one of the UK’s most distinctive forms of construction. Traditionally, masonry-based constructions included solid walls. However, from the 1930’s onwards, the use of a cavity wall construction was introduced, and became a dominant form of building construction in the UK. Cavity walls are comprised of two parts: an outer masonry skin, and an inner masonry skin, separated from the outer skin by a gap (the cavity). The two skins are linked together by wall ties to increase the strength of the construction. The cavity serves as a barrier against moisture intrusion and as a space for insulation. However, despite the common presence of insulation in the cavity, such building constructions often suffer from problems of thermal bridging - e.g. via wall ties, or other abutments between the inner and outer skins of the building’s construction.

[0007] As an alternative to masonry-based constructions, frame-based building constructions are also known in the art. Timber frame construction is one of the oldest types of wall construction, but such constructions are prone to pest infestations, rot, and may have poor fire performance not meeting modern standards for fire resistance. As a solution to this, the use of prefabricated light gauge steel framing systems for building construction is a recognised construction technology that has been employed in the UK and worldwide. Light gauge steel framing systems generally consist of structural frames fabricated using cold formed steel sections. The use of light streel framing systems has various advantages over e.g. timber frame constructions and masonry constructions, in that they are generally durable, have good fire performance if protected properly, and are cost efficient. External or internal sheathing insulation may be provided around the frame, as well as insulation within the frame. However, these constructions also suffer from problems of thermal bridging, in particular at abutment points within the construction. There has been a push in recent years toward ever more thermally efficient building constructions that provide for a fast and easy erection and installation on site and are also able to meet recently revised fire safety regulations.

[0008] The present invention has been devised in light of the above considerations.

[0009] Summary of the Invention

[0010] The present inventors have realised that by providing a dual-skin frame system in which the building construction includes separate inner and outer frame structures, in combination with a selected insulation material, it is possible to provide a building construction which allows for relatively straightforward construction system, and which can additionally provide a cavity which extends continuously (i.e. about the entire perimeter of the building construction) between the inner and outer frame structures, thereby allowing for a substantially continuous insulation envelope to be provided between the inner and outer frame structures. This can allow the building construction to be substantially thermal bridge free.

[0011] The arrangement differs from known modern methods of constructions e.g. those employing prefabricated open or closed (ready insulated) panel systems which are respectively connected together to define one or more sidewalls of the building construction. In such known building arrangements, abutments are present between the panels at corner regions of the building construction. Because of these abutments and the presence of a single frame construction, it is therefore not possible to provide a cavity which extends substantially continuously between an inner skin / leave and an outer skin / leave of these types of building construction about the entire building perimeter. Hence, repeating thermal bridging between an inner skin / leave and an outer skin / leave of these types of building construction can therefore occur, e.g. mortar joints and wall-ties in masonry construction or timber or steel studs in a single framed construction, as well as at abutment points. By providing a building construction in which the inner and outer frame are configured to be separate from one another, the presence of such repeating thermal bridging is in principle avoided.

[0012] Accordingly, in a first aspect, the present invention provides a building construction comprising a double frame wall structure comprising an inner frame structure and an outer frame structure, each of said inner frame structure and outer frame structure comprising a plurality of upstanding column members connected by horizontally-extending elements, the inner and outer frame structure being separate from one another and arranged in a spaced manner such that a cavity that extends about a perimeter of the building construction is defined between the inner and outer frame structures, wherein the cavity is filled with an insulation material to thereby provide a substantially continuous insulation envelope between the inner and outer frame structures. As noted above, it has been found that this arrangement allows for a relatively simple construction which is substantially thermal bridge free between the inner and outer frame structures, and which has effective insulation performance.

[0013] The term “separate” is used herein to define that there is no direct physical engagement or connection between the inner and outer frame structures. Such an arrangement can help prevent thermal bridging between the inner and outer frame structures. Preferably, there are no abutments provided between the inner frame structure and the outer frame structure. That is, preferably there are no abutments provided between the upstanding column members or horizontally-extending elements of the inner frame structure, and the upstanding column members or horizontally-extending elements of the outer frame structure. In other words, in building constructions according to the invention, it is possible to draw a continuous and uninterrupted line that extends about the entire perimeter of the building construction through the insulated cavity.

[0014] As discussed in further detail below, the inner and outer frame structure may be in indirect connection with one another- for example, via one or more floor structures of the building construction, via insulation material provided in the cavity between the inner and outer frame structures, or via e.g. window or door frames that necessarily span between both inner and outer parts of the building structure . However, preferably such indirect connection is selected to minimise or eliminate thermal bridging between the inner and outer frame structures.

[0015] The building construction may have a y-value (representing total thermal bridging heat losses for a building construction and calculated as defined in BRE IP 1 / 06 (2006) and BR497 (2016)) of 0.08 or less, more preferably 0.04 or less. A y-value of 0.04 or less is generally understood as being substantially thermal-bridge free.

[0016] The inner and outer frame structure may be configured such that they are substantially structurally independent of one another. The phrase “substantially structurally independent” is used herein to define that there is no significant load transfer between the inner frame structure and the outer frame structure of the building construction. In this regard, each of the inner frame structure and the outer frame structure may be separately fixed to one or more floor structures of the building construction - e.g. they may be respectively and separately fixed to a ground bearing slab, a block and beam floor structure, or floor joist(s) of the building construction.

[0017] As noted above, a substantially continuous insulation envelope is provided between the inner and outer frame structures. The insulation envelope is continuous in the sense that it extends about a perimeter of the building construction - e.g. the insulation envelope extends around the corners of the building construction in a manner that is not possible in conventional building construction arrangements having abutments at corner portions of the building construction. The building construction may be configured such that at any selected portion of the building construction, the insulation material is interposed between the inner frame structure and the outer frame structure. The insulation material may occupy substantially the entire cavity defined between the inner and outer frame structure. That is, it may occupy 90% or more, 95% or more, 98% or more, 99% or more, or substantially 100% of the cavity volume defined between the inner and outer frame structures. In some arrangements, some cavity volume may be taken up by conduits (e.g. conduits for electrical connections of the building construction). In such arrangements, the insulation material may occupy substantially the remaining free space in the cavity, excluding the volume of any conduits present within the cavity. That is, the insulation material may occupy 90% or more, 95% or more, 98% or more, 99% or more, or substantially 100% of the remaining free space in the cavity, excluding the volume of any conduits present within the cavity.

[0018] By providing such an arrangement, improved thermal performance of the building construction can be provided in comparison to known building constructions. In comparison, in conventional building constructions including a cavity, it is typically not possible for insulation material to occupy substantially the entire cavity in view of the requirement for the presence of other components within the cavity which structurally connect components of the building construction defining either side of the cavity. As one example, in many conventional wall constructions (e.g. masonry cavity wall construction) wall-ties are required within the cavity to provide structural support between inner and outer leaves of the cavity wall. The requirement for other components of the building constructions to be present in the cavity of known building constructions (in particular, components which extend across the full width of the cavity such as wall-ties) can limit or prevent distribution of conventional insulating materials (such as mineral fibre) within the cavity, such that at various locations within the cavity, no insulation material is interposed between inner and outer leaves of the cavity wall construction. In some building constructions according to the present invention, no other components (other than the insulating material) are provided within the cavity which extend across the entire width of the cavity between the inner and outer frame structure (e.g. to abut both the inner and outer frame structures). Preferably the building construction includes no frame-ties which extend between the inner and outer frame structures (i.e. preferably no frame-ties are provided within the construction). This can further help prevent thermal bridging between the inner and outer frame structures.

[0019] Preferably, the insulation material is a material that is flowable at least at the time of assembly of the building construction. By using a material that is flowable at least during assembly of the building construction, it may be possible to fill the cavity between the inner and outer frame structure of the building construction in a facile manner. In particular, one key advantage of use of a material that is flowable at least during assembly of the building construction is that such materials tend to be self-compacting and self-levelling to some degree: this can help to ensure proper formation of the continuous insulation envelope during assembly of the building construction, because the flowable material can self-level to fill gaps within the cavity as it is filled. This technical effect may not be realised when non-flowable insulating materials (e.g. mineral fibre insulating materials, set foam materials, cork, vermiculite, wood fibre and the like) are used. Whilst the material is preferably flowable at least during the time of assembly of the building construction, it may later become non-flowable, e.g. may set to become a non-flowable (solid) material. The use of an insulation material that is flowable at least at the time of assembly of the building construction has particular synergistic effects in terms of ease of assembly of the building construction when combined with a building construction including a cavity which extends substantially continuously (i.e. about the entire perimeter of the building construction) between the inner and outer frame structures, as the flowable material is able to readily flow to fill the entire cavity, thereby reducing instances of incomplete filling of the cavity during assembly of the building construction.

[0020] Preferably the insulation material is a foamed concrete material. Use of a foamed concrete material may offer various advantages over other known insulation materials. Foamed concretes can be provided to be flowable at least at the time of assembly of the building construction, leading to the technical advantages noted above. Furthermore, because a significant component of foamed concrete is air, foamed concrete precursor compositions can be readily transported to a construction site, and manufactured in-situ (‘on-site’), thereby resulting in a lower environmental burden as compared with transportation of large amounts of pre-manufactured insulation materials, as required in many traditional constructions. Finally, foamed concretes have been found to provide a particular good balance of thermal conductivity, durability and fire resistance when used for this purpose. Building constructions employing foamed concrete as an insulation material may therefore find particular good compliance with various regulatory standards or metrics.

[0021] The foamed concrete material may be a material having a density of 1000 kg / m3or less, more preferably 500 kg / m3or less, more preferably 400 kg / m3or less. In some embodiments, the foamed concrete material may be a foamed concrete having a density as low as 200 kg / m3or 100 kg / m3. Use of a foamed concrete having a density of 400 kg / m3or less has been found to offer particularly suitable thermal performance for building constructions according to the present invention. Foamed concrete having a density of 400 kg / m3or less may be referred to as low-density foamed concrete.

[0022] Preferably the inner frame structure and / or the outer frame structure are formed from noncombustible materials, i.e. materials having an A1 rating as measured according to BS EN 13501-1 :2007+A1:2009. Preferably the inner frame structure and / or the outer frame structure are formed from metal. Conveniently they may be formed from steel, such as light gauge steel. It is contemplated that other materials may be used, however the use of light-gauge steel has been found to be particularly appropriate for use in building constructions according to the present invention in view of the ease of manufacture, durability and non combustibility afforded by this material. Consequently, it does not burn, provide an ignition source or add to the fuel load. Furthermore, if adequately protected, they can achieve high levels of the fire resistance. Preferably the inner frame structure and / or the outer frame structure are not formed from wood.

[0023] As noted above, the inner frame structure comprises a plurality of upstanding column members connected by horizontally-extending cross-bar elements (also referred to as girts). This combination of column members and cross-bars defines one or more sidewalls / endwalls of the inner frame structure. Typically, the inner frame structure may comprise four sidewalls / endwalls, e.g. two opposing sidewalls, and two opposing endwalls, wherein the sidewalls and endwalls are arranged to be perpendicular to one another to thereby defined a substantially rectangular form, although it will be appreciated that the specific shape of the building construction is not particularly limited.

[0024] In a similar fashion, the outer frame structure also comprises a plurality of upstanding column members connected by horizontally-extending cross-bar elements (also referred to as girts). These components may thereby define one or more sidewalls / endwalls of the outer frame structure. Typically, the outer frame structure may comprise four sidewalls / endwalls, e.g. two opposing sidewalls, and two opposing endwalls, wherein the sidewalls and endwalls are arranged to be perpendicular to one another to thereby defined a substantially rectangular form, although it will be appreciated that the specific shape of the building construction is not particularly limited.

[0025] The inner frame structure and / or the outer frame structure may additionally comprise one or more bracing elements.

[0026] The column members, horizontally-extending cross-bars and / or bracing members (collectively referred to herein as ‘constructional members’ for convenience) may conveniently be provided in the form of single lengths of light gauge steel. The lengths may have a ‘C-shaped’ sectional shape, typically referred to in the art as ‘C Section’ or ‘C channel’ lengths. Other shaped sections are also contemplated (e.g. T sections), but ‘C section’ lengths are found to offer particular convenience in respect of ease of manufacture and assembly of the building construction. The constructional members may be configured for connection to form respective frame structures in any suitable manner. One suitable manner includes riveted connection of the lengths.

[0027] In some arrangements, the inner frame structure and / or the outer frame structure may comprise horizontally-extending and / or vertically-extending conduits. The horizontally-extending conduits may be located within the horizontally-extending elements of the inner and / or outer frame structures. The vertically-extending conduits may be located within the upstanding column members of the inner and / or outer frame structures. Preferably at least the inner frame structure comprises such horizontally-extending and / or vertically-extending conduits. Preferably at least the inner frame structure comprises at least one horizontally-extending conduit, and at least one vertically-extending conduit. The at least one horizontally-extending conduit and the at least one vertically-extending conduit may be arranged to connect to one another. In other words, the inner frame structure may comprise a network of horizontally-extending and vertically-extending conduits.

[0028] The horizontally-extending and / or vertically-extending conduit(s) may be configured to provide a conduit for power transmission from one location within the building construction to another location within the building construction. For example, the conduits may contain one or more power-transmitting elements, e.g. wires. A frame structure comprising such conduits for power transmission may be referred to for convenience as a ‘power wall’.

[0029] Where such conduits are provided, one or more access points may be provided for access to said conduits. The access points may comprise apertures formed in the respective frame structure, e.g. holes formed in the horizontally-extending elements and / or upstanding column members of the inner and / or outer frame structures. A plurality of such access point may be provided.

[0030] The precise location of the conduit(s) is not particularly limited, and it will be understood that appropriate location of conduits can be selected based on needs for the particular building construction in question. However, in some arrangements, at least one of the frame structures (preferably the inner frame structure) comprises one or more of the following: i. a horizontally-extending conduit provided at a height of about 400-500mm, e.g. at about 450 mm from the bottom of the frame structure; ii. a horizontally-extending conduit provided at a height of about 1100-1300mm, e.g. at about 1200 mm from the bottom of the frame structure; and / or iii. a horizontally-extending conduit provided at a height of about 100-200mm, e.g. at about 150 mm from the top of the frame structure.

[0031] Providing horizontally-extending conduits at such locations can allow suitable conduits for locating power-transmitting elements in appropriate zones for convenient location of e.g. power sockets, power junction boxes etc.

[0032] The size of the conduits is not particularly limited, however preferably the conduits are sized to fit within frame members of the frame structure (e.g. to fit within the horizontally-extending elements and / or upstanding column members. The conduits may have a widest lateral dimension (i.e. a dimension perpendicular to their direction of extension) of 50 mm to 250 mm, e.g. 200mm or less, 150 mm or less, or 100 mm or less. The longitudinal dimension of the conduit may vary depending on the configuration of the building construction. In some arrangements, the or each conduit may extend for substantially the entire length of a wall of the building construction. In other arrangements, the or each conduit may extend for only part of the length of a wall of the building construction.

[0033] Whilst the provision of such conduits may find particular application in the context of building constructions according to the first aspect, it is contemplated that such conduits may also find broader applicability in any building construction that utilises a framework structure as part of the building construction. For example, in a further aspect, the present disclosure contemplates a building construction comprising a frame structure comprising a plurality of upstanding column members connected by horizontally-extending elements, wherein the frame structure comprises one or both of: horizontally-extending conduits located within the horizontally-extending elements; and / or vertically-extending conduits located within the upstanding column members. Optional features discussed above in relation to provision of such conduits apply also to this further aspect, as appropriate.

[0034] The inner frame structure and the outer frame structure may be spaced to define a cavity having a width of from 100 mm to 500 mm, from 200 mm to 400 mm, or from 250 mm to 350 mm, e.g. about 300 mm. The cavity width may be variable, i.e. it may differ at different points within the cavity, within the above ranges. Such cavity widths may provide for a suitable cavity volume to provide effective insulation for the building construction. The insulation material preferably extends across substantially the entire width of the cavity. That is, preferably a minimum thickness of insulation of 100 mm or more is provided between the inner and outer frame structures. The larger the cavity width, the more effectively heat transfer across the cavity may be reduced. However, particularly large cavities may not be practicable from a manufacturing viewpoint. It has been found that provision of a cavity having a maximum width of about 300 mm may be particularly suitable.

[0035] The building construction may comprise a plurality of pairs of inner and outer frame structures, wherein each pair of inner and outer frame structures respectively define wall portions of one storey (i.e. ‘level’) of the building construction. Respective storeys / levels of the building construction may be separated by a floor structure of the building construction - i.e. a floor structure may be interposed between respective pairs of inner and outer frame structures. The top storey of the building structure may be defined by a roof structure.

[0036] As an example, the building construction may include a ‘ground storey’ floor structure (which may be e.g. a ground bearing slab, a block and beam floor structure or any other suitable floor structure). A first pair of inner and outer frame structures may be separately fixed to the ‘ground storey’ floor structure, e.g. by being strapped to the foundations, to thereby define wall portions of the ground floor of the building construction. A further floor structure may be provided above (and supported by) the first pair of inner and outer frame structures to define a ‘1ststorey’ floor structure. Conveniently this further floor structure may comprise a plurality of horizontallyextending joists which extend between, and are supported by, horizontally-extending elements of the inner frame structure and / or outer frame structure. A second pair of inner and outer frame structures may be separately fixed to the ‘1st storey’ floor structure, to thereby define wall portions of the 1ststorey of the building construction. It will be understood that such an arrangement can be continued so as to define 2nd, 3rd, 4thand further storeys of a multi-storey building construction. The uppermost pair of inner and outer frame structures may support a plurality of rafters and / or purlins which are configured to define part of a roof structure.

[0037] It will be understood that in the arrangement described above, whilst the inner and outer frame structures in each pair defining a given building storey / level are separate and not in direct contact, indirect contact between the inner and outer frame structure is nevertheless present, via floor structures of the building construction (as well as via insulating material in the cavity between the inner and outer frame structures in each pair). That is, one or more abutments or junctions are present between the inner frame structure and the floor structure, and the outer frame structure and the floor structure. Thermal bridging at such junctions can be minimised by (i) providing a thermally insulating layer and / or (ii) minimising the contact area at such junctions.

[0038] The building construction may comprise one or more boarding layers which are fixed relative to the inner frame structure and / or relative to the outer frame structure.

[0039] Preferably an inner side of the inner frame structure is lined with boarding, to thereby define an inner skin for the double frame wall structure of the building construction.

[0040] Preferably an outer side of the outer frame structure is lined with boarding, to thereby define an outer skin for the double frame wall structure of the building construction.

[0041] The phrase ‘lined with boarding’ is used here to define that one or more boards of material may be attached to component parts of the inner / outer frame structure. The boards may be attached in any suitable manner. In one suitable arrangement, the boards may be attached with screws, e.g. with self-tapping screws. The screws may be formed from steel or any other suitable materials.

[0042] That is, in a preferred arrangement, the cavity between the inner and outer frame structures may be at least partially defined by boarding provided on an inner side of the inner frame structure and / or on an outer side of the outer frame structure. The boarding / board material may comprise a waterproof, or water resistant board. This is particularly preferred for boarding provided on the outer side of the outer frame structure. Provision of waterproof or water resistant boarding in this manner can allow the boarding to act as a permanent shutter to the outside face of the outer frame structure. Conveniently, the boarding may comprise cement board.

[0043] One or more cladding layers may be provided on the inner and / or outer skin of the double frame wall structure. The specific composition and arrangement of cladding layers may be selected based on desired specifications of the building.

[0044] In some arrangements, a plasterboard (also referred to as wallboard) layer may be provided to clad an inner skin of the double frame wall structure. The plasterboard may have a predetermined fire resistance. Preferably, the plasterboard has a fire classification of A2-s1 or A1 in accordance with BS EN 13501-1 :2007+A1:2009. This can allow the building construction to meet required fire safety regulations.

[0045] In some arrangements, a protective membrane is provided to clad an outer skin of the double frame wall system. The protective membrane may be a waterproof or water-resistant membrane. Preferably the protective membrane is breathable. That is, the membrane may be water vapour resistant to less than 0.6MNs / g (0.12 Sd) when tested in accordance with BS EN ISO 12572 using the set of conditions C and using five test specimens. This membrane may act as a weather-proof layer whilst still allowing water vapour to be passed to the outside of the building construction. One example of a suitable membrane is DuPont Tyvek Housewrap, which has a vapour resistance of 0.05 GN.s / kg.m to BS EN ISO 12572. Equally, vapour control layer is used to clad a skin of inner frame system. One example of a suitable membrane is Dupont AirGuard Control, which has a vapour resistance of 25 GN.s / kg.m

[0046] In some arrangements, one or more further insulating layers may be provided to clad an outer skin of the double frame wall system. Provision of further insulating layers may synergistically work together with the internal insulating material to provide for further improved thermal performance of the building construction. Where such insulating layers are provided, they may include a waterproofing layer. For example, when using conventional insulation material (mineral fibre etc) a waterproof breathable membrane (such as Tyvek®) might be provided at the inner side of insulation, at the interface of the frame and the insulation, or at the outer side of the insulation. Such arrangement may help reduce or minimise water ingress into the building construction.

[0047] In some arrangements, an aesthetic cladding layer may be provided as the outermost cladding layer of the outer skin of the double frame wall system. An aesthetic cladding layer is a layer selected to achieve a particular aesthetic effect for the building construction. Aesthetic cladding layer may comprise e.g. a layer of brick slips, to provide the aesthetic of a masonry construction for the building construction. Where such an aesthetic cladding layer is provided, a cladding support structure may be provided to assist in affixing the aesthetic cladding layer to the outer skin of the double frame wall system. In one suitable arrangement, the cladding support structure may comprise a plurality of vertically- and horizontally extending railings, to which the aesthetic cladding layer can be affixed.

[0048] The building construction may have a design energy performance score of greater than 90 according to the Standard Assessment Procedure (SAP) version 10.2 (11-04-2023). Preferably, the building construction has a design energy performance of 92 or more, 93 or more, 94 or more, 95 or more, 96 or more, 97 or more, 98 or more, 99 or more, or 100. The SAP rating is based on the energy costs associated with the building construction design which is affected by factors such as thermal insulation of the building fabric. It is adjusted for floor area so that it is essentially independent of dwelling size for a given built form. The SAP rating is expressed on a scale of 1 to 100, the higher the number the lower the running costs. In this sense, an SAP rating of from 90 to 100 indicates excellent energy performance for the building construction.

[0049] In a second aspect, the present invention provides a method of assembly of a building construction the method including steps of: providing a plurality of constructional members and assembling said constructional members to form an inner frame structure and an outer frame structure, the inner and outer frame structure being separate and arranged in a spaced manner such that a cavity that extends about a perimeter of the building construction is defined between the inner and outer frame structures; and filling the cavity with an insulation material to thereby provide a substantially continuous insulation envelope between the inner and outer frame structures.

[0050] The step of providing the plurality of constructional members may in some methods include a step of forming such members on-site (e.g. using appropriate machining equipment to cut and / or bend lengths of a suitable material into a predetermined form). On-site is used herein to define that the construction members are manufactured at substantially the same location as the building construction is erected (e.g. within 1km of the site, preferably within 0.5 km of the site, preferably within 0.2km of the site). Advantageously, where the members are formed onsite, this can increase the efficiency of assembly of the building construction, and furthermore can reduce costs associated with the building construction by removing the requirement for suitable constructional members to be transported from their place of manufacture to the building site. There may also be environmental benefits associated with such a method - the carbon footprint of the building construction may be reduced by removing the requirement for suitable constructional members to be transported from their place of manufacture to the building site. Whilst there are many advantages to forming the constructional members on-site, it is also contemplated that in some methods, the step of providing a plurality of constructional members may including acquiring said members from another source e.g. by purchase from a third-party provider of such members.

[0051] The plurality of constructional members may include column members, horizontally-extending cross-bar elements (girts) and / or bracing members as discussed above. Preferably, these are formed from light gauge steel, although the use of other materials is contemplated, as noted above. The step of assembling the constructional members to form an inner frame structure and an outer frame structure may be performed by attaching the constructional members together in any suitable fashion e.g. by riveting the constructional members together to form the desired frame shape.

[0052] The step of assembling the constructional members to form an inner frame structure and an outer frame structure may include sub steps (performed in any suitable order) of: arranging a plurality of column members in an upstanding fashion and connecting these to one or more horizontally-extending elements to thereby define one or more sidewalls / endwalls of the inner frame structure; arranging a plurality of column members in an upstanding fashion and connecting these to one or more horizontally-extending elements to thereby define one or more sidewalls / endwalls of the outer frame structure.

[0053] Conveniently, the inner frame structure may be assembled such that a first set of horizontallyextending elements provide a top rail of the inner frame structure, and such that a second set of horizontally-extending elements provide a bottom rail of the inner frame structure. The column members may extend between the top and bottom rails of the inner frame structure. One or more further horizontally-extending elements may be interposed between the top and bottom rails of the inner frame structure, e.g. where greater structural rigidity is desired.

[0054] The outer frame structure may have an analogous arrangement, i.e. may be assembled such that a first set of horizontally-extending elements provide a top rail of the outer frame structure, and such that a second set of horizontally-extending elements provide a bottom rail of the outer frame structure. The column members may extend between the top and bottom rails of the outer frame structure. One or more further horizontally-extending elements may be interposed between the top and bottom rails of the outer frame structure.

[0055] Arrangements in which the inner and outer frame structure each comprise horizontallyextending top and bottom rails may be particularly preferred, because the top and bottom rails can provide convenient attachment points for attachment of the frame structures to further components of the building construction. For example, once assembled, the inner and outer frame structure may be attached to one or more floor structures of the building construction via their top and / or bottom rails. The method of assembly of the building construction may include step of arranging a plurality of horizontally-extending joists to extend between, and be supported by, horizontally-extending elements of the inner frame structure and / or outer frame structure. The joists may be supported by the horizontally-extending elements of the inner frame structure and / or outer frame structure by being disposed to rest on top of the elements. That is, the joist may lie in a different horizontal plane to the elements & “extend between” as used above does not require that the joists lie in the same horizontal plane at the elements.

[0056] The method may further include assembling a plurality of pairs of inner and outer frame structures, said assembly being as described above, wherein each pair of inner and outer frame structures respectively define wall portions of one storey (i.e. ‘level’) of the building construction. For example, the method may include: providing a first floor structure; fixing a first pair of inner and outer frame structures to the first floor structure to thereby define wall portions of a ground storey of the building construction; arranging a second floor structure to be supported by the first pair of inner and outer frame structures; and fixing a second pair of inner and outer frame structures to the second floor structure to thereby define wall portions of a 1st storey of the building construction.

[0057] The method of assembly of the building construction may include a first boarding step of lining at least an inner side of the inner frame structure with boarding, to thereby define an inner skin for the double frame wall structure of the building construction.

[0058] The method may include a second boarding step of lining at least an outer side of the outer frame structure with boarding, to thereby define an outer skin for the double frame wall structure of the building construction.

[0059] In methods including such steps, the cavity between the inner and outer frame structures may be at least partially defined by boarding provided on an inner side of the inner frame structure an outer side of the outer frame structure. These boarding steps may therefore be performed prior to, or concurrently with, the step of filling the cavity with an insulation material.

[0060] In some preferred methods, the first boarding step and / or the second boarding step may be performed as a series of partial boarding steps: that is, the inner side of the inner frame structure may be partially lined with boarding in a first partial boarding step, and one or more further partial boarding steps may be performed subsequently to line the remaining unboarded portion of the inner side inner frame structure. Analogously, the outer side of the outer frame structure may be partially lined with boarding in a first partial boarding step, and one or more further partial boarding steps may be performed subsequently to line the remaining unboarded portion of the outer side of the outer frame structure. Such methods may be particularly advantageous where the step of filling the cavity with an insulation material is performed substantially concurrently with the boarding steps, because it can allow for easy access to the cavity during the filling process.

[0061] The step of filling the cavity with an insulation material to thereby provide a continuous insulation envelope between the inner and outer frame structures may be performed in any suitable manner. As discussed above in relation to the first aspect, the insulation material is a preferably a material that is flowable at least at the time of assembly of the building construction, e.g. is preferably a foamed concrete material, and more preferably a low-density foamed concrete material. Such materials may be suitable filled into the cavity by methods such as pumping or spraying.

[0062] In one particularly preferred method, the insulation material is pumped into the cavity between partial boarding steps of partially boarding the inner side of the inner frame structure and the outer side of the outer frame structure. That is, the following series of steps may be performed: i. the inner side of the inner frame structure and the outer side of the outer frame structure are partially lined with boarding; ii. the cavity is partially filled with the insulation material, to a level equal to or less than the level of the partial boarding; iii. one or more further partial boarding steps are performed to line the remaining unboarded portions of the inner side of the inner frame structure and the outer side of the outer frame structure; iv. one or more further cavity filling steps are performed, to fill the remaining portion of the cavity.

[0063] The term “partially lined” is used herein to define that at least part of the frame structure is not lined. Suitably, the inner side of the inner frame structure and the outer side of the outer frame structure are partially lined with boarding such that the boarding extends partially in a vertical direction. Each partial boarding step may board a portion of the frame structure equivalent to 10% or more, 20% or more, 30% or more, 40% or more or 50% or more of the height of the frame structure. The precise amount of partial boarding to be completed may depend on the desired maximum depth of insulation filled in each partial filling step.

[0064] This method may be particularly advantageous where the insulation material is a material that is flowable at least at the time of assembly of the building construction, but which subsequently sets to become non-flowable. By filling the cavity in a series of partial cavity filling steps, the insulating material can be allowed to set (or partially set) in layers, with one or more further layers of insulating material being subsequently added on top of the first set (or partially set) layer. This may provide structural and thermal performance advantages compared to methods where the cavity is entirely filled in a single filling step. For example, where the insulation material is foamed concrete, the foam structure can collapse or partially collapse where a large volume of material is filled into the cavity at one time - this may be a particular problem for the foamed concrete filling the lower half of the cavity, due to the weight of material above. By filling the cavity in a series of partial filling steps and allowing the foamed concrete in the cavity to set between partial filling steps, this problem can be avoided.

[0065] It is also contemplated that in some methods, at least the outer frame structure may be entirely boarded before the step of filling the cavity with the insulating material. For example, in one method, an outer side of the outer frame structure may be entirely boarded with boarding, to thereby define an outer skin. One or more further cladding layers (insulation, breathable membrane etc- see discussion below) may then be arranged being arranged to clad the outer skin. Following this, the following steps may be performed: i. the inner side of the inner frame structure is partially lined with boarding; ii. the cavity is partially filled with the insulation material, to a level equal to or less than the level of the partial boarding; iii. one or more further partial boarding steps are performed to line the remaining unboarded portions of the inner side of the inner frame structure; iv. one or more further cavity filling steps are performed, to fill the remaining portion of the cavity.

[0066] The insulation material may in some methods be manufactured or processed on-site (e.g. where the insulation material is foamed concrete, a foaming step of foaming a precursor mixture to form the foamed concrete may be performed on-site). As noted above, on-site is used herein to define that the manufacturing or processing step is performed at substantially the same location as the building construction is erected (e.g. within 1km of the site, preferably within 0.5 km of the site, preferably within 0.2km of the site). Advantageously, where one or more steps involved in manufacturing the insulation material are performed on-site, this can increase the efficiency of assembly of the building construction, and furthermore can reduce costs associated with the building construction by removing the requirement for the finished insulation material to be transported from its place of manufacture to the building site - it may be easier to transport one or more precursor materials used in manufacturing the insulation material than to transport the insulating material itself, in particular where the insulation material undergoes a significant volume changes during the manufacturing process (as in the case of foamed materials). There may also be environmental benefits associated with such a method - the carbon footprint of the building construction may be reduced by removing or reducing transportation requirement relating to transportation of the insulation material to the building site. The method may include further steps of arranging one or more further cladding layers on the inner and / or outer skin of the double frame wall structure. The further cladding layers may be selected from one or more of:

[0067] (i) a plasterboard layer, said layer optionally having a fire classification of A2-s1 or A1 in accordance with BS EN 13501-1 :2007+A1:2009;

[0068] (ii) a protective membrane;

[0069] (iii) a further insulating layer;

[0070] (iv) an aesthetic cladding layer.

[0071] In some arrangements multiple of each such layers may be provided. For example, multiple protective membranes may be provided.

[0072] Further details about these further cladding layers are discussed above in relation to the first aspect. The step of arranging one or more further cladding layers on the inner and / or outer skin of the double frame wall structure is preferably performed after the step of filling the cavity with the insulating material, to ensure that such further layers do not obstruct access to the cavity - although as noted above, this is not essential for methods where e.g. the outer frame structure is fully boarded before the step of filling the cavity with the insulating material. In such method, the step of arranging one or more further cladding layers on outer skin of the double frame wall structure may be performed at any time after boarding of the outer frame structure.

[0073] The invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided.

[0074] Summary of the Figures

[0075] Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which:

[0076] Figure 1 shows a schematic cross-sectional view of a conventional modular building construction, the cross-section being taken in a horizontal plane through the building construction.

[0077] Figure 2 shows a schematic cross-sectional view of a building construction according to the present invention, the cross-section being taken in a horizontal plane through the building construction.

[0078] Figure 3 shows a schematic cutaway perspective view of a building construction according to the present invention. Figure 4 is a flowchart for a method of assembling a building construction according to the present invention.

[0079] Figure 5 is a flowchart for an exemplary method of filling a cavity of a building construction according to the present invention with insulation.

[0080] Figure 6 is a schematic diagram illustrating a first method as described in relation to Figure 5.

[0081] Figure 7 is a schematic diagram illustrating a second method as described in relation to Figure 5.

[0082] Figures 8(a), (b) and (c) are respectively plan sectional, vertical sectional, and internal wall elevation views of part of a building construction that includes conduits for power transmission provided in the inner frame structure.

[0083] Figure 9 is a perspective view of part an alternative building construction that includes a frame structure having conduits, and access points for said conduits, formed therein.

[0084] Detailed Description of the Invention

[0085] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference.

[0086] As noted above, Fig. 1 shows a schematic cross-sectional view of a conventional modular building construction 100. This building construction utilises prefabricated frame-based panels 101a,b,c,d, which are respectively connected together to define first to fourth sidewalls of the building construction and defining an inner skin 102 and an outer skin 103 of the double frame wall structure of the building construction. Each panel comprises a frame having a substantially cuboid shape, and defining a cavity which is filled with insulation 104 which is typically mineral fibre. It can be seen that the panels abut one another to provide abutments at the corners of the building construction - the abutment between panels 101a and 101b is indicated by the dashed circle in this figure, as an example, although it can be seen that similar abutments are provided at all junctions between panels forming the building construction. Because of these abutments resulting from the configuration of the modular panel construction, whilst each panel comprises a respective cavity which is filled with insulation, it is not possible to provide a cavity which extends substantially continuously about the entire perimeter of the building construction - in other words, there are breaks in the insulation envelope in this building construction. A consequence of this is that thermal bridging can occur at the abutment points between panels, as a result of these breaks in insulation, thereby allowing transfer of heat from the inner skin 102 to the outer skin 103. In contrast to such prior art arrangements, building constructions according to the present invention are illustrated in Fig. 2 and Fig. 3.

[0087] Fig 2. shows a schematic cross-sectional view of a building construction 1 according to the present invention, the cross-section being taken in a horizontal plane through the building construction. The building construction comprises an inner frame structure 2 and an outer frame structure 3, each of said inner frame structure 2 and outer frame structure 3. The inner frame structure 2 comprises comprising a plurality of upstanding column members (not shown) connected by horizontally-extending elements 4a,b,c,d. The outer frame structure 3 comprises comprising a plurality of upstanding column members (not shown) connected by horizontallyextending elements 5a,b,c,d.

[0088] The inner and outer frame structures 2, 3, are separate from one another (i.e. they are not in direct physical connection) and are arranged in a spaced manner such that a cavity 6 is defined between the inner and outer frame structures. The cavity 6 extends about a perimeter of the building construction, including around corner portions of the building construction. The cavity 6 is filled with an insulation material 7 to thereby provide a substantially continuous insulation envelope between the inner and outer frame structures. The insulation envelope is continuous in the sense that it extends about the perimeter of the building construction, within the cavity 6. It can be seen that at any selected portion of the building construction, the insulation material 7 is interposed between the inner frame structure 2 and the outer frame structure 3. The inner frame structure provides an inner skin for the building construction The outer frame structure provides an outer skin for the building construction. In this sense, the building construction is referred to as comprising a ‘dual-skin’ frame system. Because the construction comprises no abutment between the inner and outer frame structures 2, 3, the cavity 6 extends substantially continuously (i.e. about the entire perimeter of the building construction) between the inner and outer frame structures 2, 3, and because a substantially continuous insulation envelope is provided between the inner and outer frame structures 2, 3, the building construction 1 can be substantially thermal bridge free, and can accordingly offer improved thermal performance in comparison to conventional arrangements as shown in Fig. 1.

[0089] Fig. 3 shows a schematic cutaway perspective view of a building construction according to the present invention. The building construction depicted is two storeys in height - i.e. it provides two distinct internal spaces arranged on top of one another, partitioned by a floor structure. In the arrangement shown, the building construction comprises two pairs of inner and outer frame structures. The first pair of inner and outer frame structures 2a, 3a define wall portions of a first storey (i.e. ‘level’) of the building construction - this may be e.g. a ground floor storey of the building construction. The second pair of inner and outer frame structure 2b, 3b define wall portions of a second storey (i.e. ‘level’) of the building construction - this may be e.g. a 1stfloor storey of the building construction. The first and second storeys are separated by a floor structure of the building construction, which in the present instance comprises a plurality of horizontally-extending joists 8, as will be discussed further below.

[0090] Each of the first and second inner frame structures, and each of the first and second outer frame structures are formed from a plurality of upstanding column members 9, 10 connected by horizontally-extending cross-bar elements 4, 5 (also referred to as girts) - these members are collectively referred ‘constructional members’ for convenience. The constructional members are conveniently provided in the form of single lengths of light gauge steel having a ‘C-shaped’ sectional shape, and width of 90 mm. The constructional embers are joined together by riveting, to form their respective frame structures. Each of the inner 2a, b and outer 3a, b frame structures has a substantially similar geometric shape, other than the inner frame structures 2a, b are slightly smaller than the outer frame structures 3a, b, such that the inner frame structures can be arranged within their respective outer frame structures whilst being spaced from the outer frame structures. For each frame structure, a first set of horizontally-extending elements provide a top rail and a second set of horizontally-extending elements provide a bottom rail, with the column members extending between the top and bottom rails. Additional horizontally-extending elements are interposed at an approximately central position between the top and bottom rails, to provide greater structural rigidity for the frame structures. The top and bottom rails of each frame structure are configured for attachment to a floor structure of the building. Whilst a ground storey floor structure is not shown in Fig. 3 (but which may be provided in any convenient manner such as e.g. by a ground bearing slab), the 1ststorey floor structure which divides the ground and 1ststoreys of the building construction is shown. As noted above, the 1ststorey floor structure comprises a plurality of horizontally-extending joists 8. Each of these joists comprises two horizontally extending chord portions (a top chord 11 and a bottom chord 12), with trusses 13 extending in an angled manner to form triangulations between the cord portions. The bottom chord 12 of each joist 8 is disposed to rest on top of, and thereby supported by, a top rail portion of the inner and outer frame structures 2a, 3a constituting the ground floor storey of the building construction. The contact area at each junction between a joist 8 and the top rail portion of the inner and outer frame structures 2a, 3a is selected to be 150 mm2or less, to minimise thermal bridging at these junctions. The top chord 11 of each joist 8 provides support for a bottom rail portion of the inner and outer frame structures 2b, 3b constituting the 1stfloor storey of the building construction.

[0091] Each pair of inner and outer frame structures 2a, b, 3a, b are separate from one another and arranged in a spaced manner. An inner side of each inner frame structure is lined with cement board 14, to thereby define an inner skin for the double frame wall structure of the building construction. An outer side of each outer frame structure is lined with cement board, to thereby define an outer skin for the double frame wall structure of the building construction. The 1ststorey floor structure also comprises a cement board lining, with cement board 14 being affixed to bottom chords of each joist 8 to define a ceiling of the ground storey. The cement boards 14 are conveniently attached to the inner / outer frame structures 2a, b, 3a, b, and to joists 8 using steel self-tapping screws (not shown), although it will be appreciated that other attachment methods may be used.

[0092] A cavity is defined between each pair of inner and outer frame structures, the cavity being at least partially defined by the cement boards which line the inner and outer frame structures. The cavity has a width of 300 mm between an inner face of the outer skin, and an outer face of the inner skin, of the double frame wall structure. The width of the cavity is slightly less when measured from inner to outer frame structures: as the constructional members of each frame structure have a width of 90 mm, the cavity is 120 mm (300 mm minus 2*90 mm) at its narrowest point. The cavity extends about a perimeter of the building construction between each pair of inner and outer frame structures - whilst such extension is not shown in Fig. 3, the cavity extends in the manner depicted in Fig. 2.

[0093] The cavity is filled with an insulation material 7, which is advantageously selected to be low- density foamed concrete, having a density of 400 kg / m3or less. Low-density foamed concrete is flowable at the time of assembly of the building construction, meaning that it can be pumped into the cavity to fill the cavity. During this cavity filling process, it is able to readily flow to fill the entire cavity, thereby reducing instances of incomplete filling of the cavity during assembly of the building construction. Accordingly, as shown in Fig. 3, the foamed concrete can fill substantially the entire cavity (i.e. >99% of the cavity volume) defined between the inner and outer frame structure, thereby providing effective thermal performance for the building structure.

[0094] Further advantageously, in the construction shown in Fig. 3, the configuration of the floor structure allows the foamed concrete insulation material to flow to fill a cavity defined within the floor structure - the space between trusses 13 of the floor joists 8 allow the foamed concrete to flow freely around the entire building envelope, thereby limiting heat transfer between adjacent stories of the building structure.

[0095] In the arrangement shown, further cladding layers are provided to clad both the inner and the outer skin of the double frame wall structure.

[0096] On the outer skin side of the double frame wall structure, the cement board is clad with (i) a protective membrane 15; (ii) an insulating layer 16; and (iii) an aesthetic cladding layer 17. Conveniently, the protective membrane 15 comprises a sheet of ‘Protect TF200 Thermo Membrane’, which has a vapour resistance of 0.36 MNs / g (0.071 Sd) to BS EN ISO 12572, although other membranes are also contemplated - this layer acts as a weather-proof layer whilst still allowing water vapour to be passed to the outside of the building construction. Conveniently, the insulating layer 16 comprises 100 mm of wood fibre insulation board (e.g. STEICO protect dry™), although other forms of insulation are also contemplated. The aesthetic cladding layer 17 in the arrangement shown comprises a brick slip layer 18 supported on a cladding support structure, said cladding support structure comprising a plurality of vertically extending railings 19 and a plurality of horizontally extending railings 20, to which the brick slip layer is affixed. This arrangement provides the aesthetic of a masonry construction for the building construction.

[0097] On the inner skin side of the double frame wall structure, the cement board is clad with a plasterboard layer 21. Similarly, the cement board 14 affixed to bottom chords of each joist 8 to define a ceiling of the ground storey is clad with a plasterboard layer 21.

[0098] The building construction as shown in Fig. 3 may have a design energy performance score of 92 or more according to the Standard Assessment Procedure (SAP) version 10.2 (11-04-2023).

[0099] Methods of assembly of building constructions according to the present invention will now be described with reference to Fig. 4-6. First, a general method for a building construction according to the present invention will be discussed in relation to Fig. 4.

[0100] In step S100, a plurality of constructional members including a plurality of members suitable for use as column members, and a plurality of members suitable for use horizontally-extending elements are provided. Features of the constructional members may be as noted above: that is, they may conveniently comprise length of C-shaped light gauge steel. The step of providing the plurality of constructional members may in some methods include a step of forming such members on-site (e.g. using appropriate machining equipment to cut and / or bend lengths of a suitable material into a predetermined form) for increased efficiency of assembly of the building construction, although the method is not limited as such.

[0101] In step S200 a plurality of column members are connected to a respective plurality of horizontally-extending elements to define first and second frame structures - detailed discussion of a suitable geometric arrangement for the column members and elements is set out above in relation to Fig. 3.

[0102] In step S300, the inner and outer frame structure are arranged in a spaced manner and fixed to a floor structure. Importantly, in some methods, this step may be performed concurrently with step S200 - that is, the relative arrangement of the inner and outer frame structures may occur during the step of connecting the plurality of column members to a respective plurality of horizontally-extending elements to define the first and second frame structures. In other words, the inner and outer frame structures may be assembled ‘in-situ’ in this spaced manner.

[0103] In step S400, boarding layers are fixed relative to the inner frame structure and relative to the outer frame structure to define respective inner and outer skins for the double frame wall structure of the building construction. As discussed above in relation to Fig. 3, the boarding layers may comprise cement board. In step S500, the cavity is filled with an insulation material. As discussed above in relation to Fig. 3, the insulation material may suitably be foamed concrete. This filling step may include pumping or spraying the foamed concrete into the cavity.

[0104] In step S600, one or more cladding layer(s) are fixed to the inner and outer skins. Some suitable forms for these cladding layers are discussed above in relation to Fig. 3.

[0105] In some methods, steps S400 and S500 may be replaced with steps S400’ and S500’ shown in Fig. 5, which is a flowchart for a method in which boarding of the inner and / or outer frame structures, and filling of the cavity are performed as a series of partial boarding and filling steps. Fig. 6 and Fig. 7 are schematic diagrams illustrating such a method.

[0106] Specifically, in Fig, 6 the following steps are performed:

[0107] - the inner side of the inner frame structure 602 and the outer side of the outer frame structure 603 are partially lined with boarding 614;

[0108] - the cavity is partially filled with the insulation material 607, to a level equal to or less than the level of the partial boarding;

[0109] - two further partial boarding steps are performed to line the remaining unboarded portions of the inner side of the inner frame structure 602 and the outer side of the outer frame structure 603;

[0110] - two further cavity filling steps are performed, to fill the remaining portion of the cavity with insulation material 607, wherein in each further filling step, the cavity is filled with insulated material to a level equal to or less than the level of boarding.

[0111] In Fig, 7 the following steps are performed:

[0112] - the outer side of the outer frame structure 703 is fully lined with boarding 714 and an insulating cladding layer 716 (and optionally further layers, not illustrated) is provided to clad this boarding. The inner side of the inner frame structure 702 is partially lined with boarding 714;

[0113] - the cavity is partially filled with the insulation material 707, to a level equal to or less than the level of the partial boarding on the inner side of the inner frame structure 702;

[0114] - two further partial boarding steps are performed to line the remaining unboarded portions of the inner side of the inner frame structure 702; two further cavity filling steps are performed, to fill the remaining portion of the cavity with insulation material 707, wherein in each further filling step, the cavity is filled with insulated material to a level equal to or less than the level of boarding. Such methods are particularly advantageous where the insulation material is foamed concrete, as the foamed concrete can be allowed to set or partially set between each partial filling step. This can help prevent collapse or partial collapse of the foam structure of the foamed concrete during the cavity filling process, thereby leading to improved structural and thermal performance of the building structure.

[0115] As will be readily understood, Fig. 6 and 7 are schematic illustrations of only part of a method of assembly of a building construction according to the present invention. Further method steps forming part of the method for assembling the building construction may be performed before, concurrently with, or after, the illustrated.

[0116] Figures 8 and 9 show various arrangements in which a frame structure of a building construction includes horizontally-extending and / or vertically-extending conduits, e.g. for power transmission from one location within the building construction to another location within the building construction.

[0117] Figures 8(a), (b) and (c) are respectively plan sectional, vertical sectional, and elevation views of part of a building construction 800 comprising an inner frame structure 802 and an outer frame structure 803 spaced to as to provide an insulated cavity 806 therebetween. The plan sectional view of Fig. 8(a) appears at first sight to have gaps in it, however it will be appreciated that the section is taken at a location which intersects both a window (apparent gap in the leftmost wall) and a door (apparent gap in the bottom-most wall): in practice, the cavity extends about substantially the entire perimeter of the building construction (in other words, it is possible to draw a continuous and uninterrupted line that extends about the entire perimeter of the building construction through the insulated cavity). That is, a substantially continuous insulation envelope is provided between the inner and outer frame structures. In particular, it can be seen the insulation envelope extends continuously around corner regions of the building construction - one such corner region is indicated with reference 807.

[0118] In these figures, the inner frame structure 802 comprises one horizontally-extending conduit 822 indicated by the dashed line in Fig. 8(a) and two vertically-extending conduits 824 indicated by the shaded squares in Fig. 8(a). The location of these conduits is best seen in Fig. 8(b) and Fig. 8 (c). The horizontally-extending conduit 822 is provided at a height of about 450 mm from the bottom of the frame structure, and has a height (i.e. its widest lateral dimension perpendicular to its direction of extension) of about 100 mm. The vertically-extending conduit 824 is arranged to connect to the horizontally-extending conduit 822. The vertically-extending conduit has a width (i.e. its widest lateral dimension perpendicular to its direction of extension) of about 100 mm, and extends from the point of connection to the horizontally-extending conduit 822, to the top of the inner frame structure. Figure 9 is a perspective view of part an alternative building construction 900 that includes a frame structure 902 having conduits (not visible), and access points for said conduits formed therein. In this construction, the frame structure 902 is attached to an external wall by a series of spacers. The frame structure 902 is formed from a plurality of horizontally-extending elements 904 and a plurality of upstanding column members 909. A plurality of access points 926a, b are provided for access to conduits provided with the horizontally-extending elements 904 and upstanding column members 909. The access points 926a comprise apertures formed in the upstanding column members 909. The access points 926b comprise apertures formed in the horizontally-extending elements 904. The horizontally-extending conduits and the vertically- extending conduits provided within the frame structure are arranged to connect to one another to thereby provide a network of conduits within the frame structure. The conduits are configured to contain one or more power-transmitting elements, e.g. wires, for power transmission from one location within the building construction to another location within the building construction.

[0119] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0120] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

[0121] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0122] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0123] Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0124] It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / - 10%.

Claims

Claims:

1. A building construction comprising a double frame wall structure comprising an inner frame structure and an outer frame structure, each of said inner frame structure and outer frame structure comprising a plurality of upstanding column members connected by horizontallyextending elements, the inner and outer frame structure being separate from one another and arranged in a spaced manner such that a cavity that extends about a perimeter of the building construction is defined between the inner and outer frame structures, wherein the cavity is filled with an insulation material to thereby provide a substantially continuous insulation envelope between the inner and outer frame structures.

2. The building construction according to claim 1 wherein the inner frame structure and outer frame structure are substantially structurally independent of one another.

3. The building construction according to claim 1 or claim 2 wherein the insulation material occupies 90% or more of the cavity volume defined between the inner and outer frame structures.

4. The building construction according to any one of the preceding claims wherein the insulation material is a material that is flowable at least at the time of assembly of the building construction.

5. The building construction according to claim 4 wherein the insulation material is a foamed concrete material.

6. The building construction according to claim 5 wherein the foamed concrete has a density of 400 kg / m3or less.

7. The building construction according to any one of the preceding claims wherein the inner frame structure and / or the outer frame structure are formed from metal, optionally steel, in particular light gauge steel.

8. The building construction according to any one of the preceding claims wherein the building construction further comprises one or more floor structures, each floor structure defining a floor portion of one level of the building construction, said floor structures optionally comprising: (i) a ground bearing slab, (ii) a block and beam floor structure, and / or (iii) a plurality of floor joists.

9. The building construction according to any one of the preceding claims wherein the building construction comprises a plurality of pairs of inner and outer frame structures, wherein each pair of inner and outer frame structures respectively define wall portions of one storey of the building construction.

10. The building construction according to any one of the preceding claims wherein the building construction comprises: a first floor structure;a first pair of inner and outer frame structures separately fixed to the first floor structure to thereby define wall portions of a ground storey of the building construction; a second floor structure supported by the first pair of inner and outer frame structures; and a second pair of inner and outer frame structures separately fixed to the second floor structure to thereby define wall portions of a 1ststorey of the building construction.

11. The building construction according to any one of the preceding claims wherein at least an inner side of the inner frame structure, and an outer side of the outer frame structure are lined with boarding, to respectively define an inner skin and an outer skin for the double frame wall structure of the building construction, and where the cavity is at least partially defined by said boarding.

12. The building construction according to any one of the preceding claims wherein one or more cladding layers are provided on the inner and / or outer skin of the double frame wall structure, said cladding layers being selected from one or more of:(i) a plasterboard layer, said layer optionally having a fire classification of A2-s1 or A1 in accordance with BS EN 13501-1 :2007+A1:2009;(ii) a protective membrane;(iii) a further insulating layer;(iv) an aesthetic cladding layer.

13. The building construction according to any one of the preceding claims wherein the building construction has a y-value representing total thermal bridging heat losses for a building construction and calculated as defined in BRE IP 1 / 06 (2006) and BR497 (2016) of 0.08 or less.

14. The building construction according to any one of the preceding claims wherein the construction has a design energy performance score of 100 according to the Standard Assessment Procedure (SAP) version 10.2 (11-04-2023).

15. The building construction according to any one of the preceding claims wherein the inner frame structure and / or the outer frame structure comprise horizontally-extending and / or vertically-extending conduits.

16. The building construction according to claim 15 wherein one or more access points are provided for access to said conduits, the access points comprising apertures formed in the respective frame structures.

17. The building construction according to claim 15 or claim 16 wherein the inner frame structure comprises one or more of the following:(i) a horizontally-extending conduit provided at a height of about 400-500mm, e.g. at about 450 mm from the bottom of the frame structure;(ii) a horizontally-extending conduit provided at a height of about 1100-1300mm, e.g. at about 1200 mm from the bottom of the frame structure; and / or(iii) a horizontally-extending conduit provided at a height of about 100-200mm, e.g. at about 150 mm from the top of the frame structure.

18. A method of assembly of a building construction, the method including steps of: providing a plurality of constructional members and assembling said constructional members to form an inner frame structure, and an outer frame structure, each of said inner frame structure and outer frame structure comprising a plurality of upstanding column members connected by horizontally-extending elements, the inner and outer frame structure being separate, and arranged in a spaced manner such that a cavity that extends about a perimeter of the building construction is defined between the inner and outer frame structures; and filling the cavity with an insulation material to thereby provide a substantially continuous insulation envelope between the inner and outer frame structures.

19. The method according to claim 18, wherein the step of providing the plurality of constructional members comprises a step of forming such members on-site using machining equipment to cut and / or bend lengths of a suitable material into a predetermined form.

20. The method according to claim 18 or claim 19 wherein the step of assembling the constructional members to form an inner frame structure and an outer frame structure comprises sub steps of: connecting a plurality of column members to one or more horizontally-extending elements, and arranging the connected column members and elements in an upstanding fashion to thereby define one or more sidewalls / endwalls of the inner frame structure; and connecting a plurality of column members to one or more horizontally-extending elements, and arranging the connected column members and elements in an upstanding fashion to thereby define one or more sidewalls / endwalls of the outer frame structure.

21. The method according to any one of claims 18 to 20, wherein the insulation material is a material that is flowable at least at the time of assembly of the building construction, and wherein the insulation material is filled into the cavity by pumping or spraying.

22. The method according to claim 21, wherein the insulation material is foamed concrete.

23. The method according to claim 22 wherein a foaming step of foaming a precursor mixture to form the foamed concrete is performed on-site.

24. The method according to any one of claims 18 to 23, wherein the insulation material is filled into the cavity in a series of partial filling steps.

25. The method according to claim 24 wherein the insulation material is foamed concrete, and wherein the foamed concrete in the cavity is allowed to set or partially set between partial filling steps.

26. The method according to claim 24 or claim 25 wherein the method comprises steps of:i. partially lining the inner side of the inner frame structure and / or the outer side of the outer frame structure with boarding; ii. partially filling the cavity with the insulation material, to a level equal to or less than the level of the partial boarding; iii. performing one or more further partial boarding steps to line the remaining unboarded portions of the inner side of the inner frame structure and / or the outer side of the outer frame structure; iv. performing one or more further cavity filling steps, to fill the remaining portion of the cavity.

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