A roof truss

Abstract

A roof truss comprising a bottom chord 2, at least one top chord 3, and an insulation support frame 7. The bottom chord 2 is configured to bear upon and be supported by two spaced apart support structures 33. The top chord 3 is connected to the bottom chord 2 and configured to support roofing material on a first side of the bottom chord 2, above it in use. The insulation support frame 7 extends from the bottom chord 2 on a second side of the bottom chord 2 opposite the first side, below it in use. The insulation support frame 7 is configured to support building insulation 61 on the second side of the bottom chord. The truss may be used in a hybrid building comprising an on-site construction and a modular building unit connected together. The truss may be configured to span both the on-site construction and the modular building unit and the insulation support frame 7 may extend only for the part of the truss spanning the on-site construction.

Description

TECHNICAL FIELD

[0001] The present invention relates to a roof truss. In particular, the present invention relates to a roof truss for use in constructing a building such as a residential building and configured to support a roofing material. According to the present invention the roof truss is modified relative to conventional roof trusses to support insulation material below the level at which the roof truss is supported by support structures within the building. BACKGROUND

[0002] In building construction, buildings, and particularly residential buildings such as houses, commonly have a pitched roof formed from a plurality of roof trusses arranged in parallel and spaced apart over an uppermost storey of the building. A roof truss is a premanufactured structure, typically formed from timber and configured to be supported by exterior walls of the building, spanning the internal volume of the building. A roof truss defines the shape of the pitched roof and supports roofing material, transferring the weight of the roof downwards onto the building walls.

[0003] A pitched roof can comprise two roof portions which slope downwardly in opposite directions from an apex (or ridge) of the roof towards respective edge regions, known as eaves. Another example comprises a single roof portion which extends from a high side at one edge of the building to a low side at an opposite edge.

[0004] In the former example, the roof trusses each comprise a pair of top chords (sometimes referred to as rafters) which extend downwardly in opposite directions from an apex of the roof, and a bottom chord (sometimes referred to as a tie beam) which extends laterally between and connects the top chords. In the latter example, the roof trusses are generally of a right-angled triangle shape, comprising a top chord which slopes downwardly from the high to the low side, and bracing beneath the top chord. In both cases, the trusses are supported by a wall structure of the building towards either end of the bottom chord, suitably by an elongate component known as a wall plate overlying the tops of the walls. The wall plate is positioned on a top surface of the wall structure, extending along its length, and is usually of a timber material. A timber wall plate is typically around 1.5” (~3.8cm) deep and secured to the top of the wall through straps that secure to the wall. The bottom chord is secured to the wall plate, for instance by nails. The walls may be formed from any known building material so long as they provide sufficient strength to support the weight of the roof structure transferred to the wall plate.

[0005] The roof space defined by the shape of the roof trusses is normally insulated, to resist thermal energy transfer through a ceiling structure of the building, which defines a lower boundary of the roof space. The insulation is conventionally positioned above an inner skin of the ceiling (that is affixed to an underside of the bottom chords of each roof truss), and extends laterally into the roof eaves. The insulation should ideally pass over the wall plate to a position adjacent an inner surface of the roof, between the top chords of adjacent trusses. This serves to insulate a void located between the bottom and top chords adjacent the eaves, in the region of the wall. Insertion of insulation into the void can however be difficult, as the opening into it from the main roof space is usually quite small. This can have the result that the void is inadequately insulated, because the insulation does not extend all the way into it over the wall plate. This can lead to cold zones (or ‘cold spots’) forming along an upper part of the wall inside the building on the uppermost storey. Consequences of this can include heat loss, and damp patches appearing on the internal surface of the inner wall skin, caused by moisture in the building condensing on the cold wall surface.

[0006] It is an aim of certain examples of the present invention to solve, mitigate or obviate, at least partly, at least one of the problems and / or disadvantages associated with the prior art. Certain examples aim to provide at least one of the advantages described below. BRIEF SUMMARY OF THE INVENTION

[0007] According to a first aspect of the present invention there is provided a roof truss comprising: a bottom chord configured to bear upon and be supported by two spaced apart support structures; at least one top chord connected to the bottom chord and configured to support roofing material on a first side of the bottom chord; and an insulation support frame extending from the bottom chord on a second side of the bottom chord opposite the first side; wherein the insulation support frame is configured to support building insulation on the second side of the bottom chord.

[0008] The roof truss according to the first aspect of the present invention differs from a conventional roof truss in that it includes the insulation support frame. An advantage of the present invention is that because insulation can be installed within the insulation support frame underneath the roof truss (or more precisely, within a void formed by the insulation support frames of a plurality of roof trusses arranged in parallel), insulation may be installed more readily to fill the whole width between support structures (such as building exterior walls) and cold spots may be avoided. Additionally, in some cases where the insulation support frame does not extend across the whole width of the building, the insulation support frame may be configured so that insulation within the frame can provide the same degree of thermal insulation as alternative insulation materials in other portions of the building. In some cases where the support structures comprise insulated wall structures, for instance comprising Structurally Insulated Panels (SIPs) the insulation support frame may be configured so that the degree of thermal insulation of insulation material to be installed within the frame will match the thermal insulation provided by the insulated wall structures. Consequently, where the insulation support frame extends up to or connects with the insulated wall structure, continuous thermal insulation can be provided to the upper storey of the building over the walls and the ceiling.

[0009] The bottom chord may comprise first and second support sections configured to be supported by the two spaced apart support structures and the insulation support frame extends from the bottom chord between the first and second support sections. In use, the support sections may rest upon and optionally be secured to a wall plate. The support sections may be undifferentiated from other portions of the bottom chord except that they are spaced apart the appropriate distance to align with wall plates mounted upon walls of the building so they can be secured to the wall plates, for instance by nailing. The support sections may be provided proximal to either end of the bottom chord. The support sections may be proximal to the connection between the bottom chord and top chords.

[0010] The insulation support frame may comprise: a ceiling support beam spaced apart from the bottom chord; and a plurality of legs connecting the bottom chord and the ceiling support beam. The ceiling support beam and the bottom chord may comprise timber beams or joists generally extending parallel to one another. The primary purpose of the bottom chord is to tie the top chords together at the level of the support structures so that the weight of roofing material does not impart a lateral force to the support structures (such as exterior building walls). In contrast the primary purpose of the ceiling support beam is to support ceiling material for instance boards (for instance plasterboard) affixed to its underside and to support the weight of insulation within the frame. As such in some examples the ceiling support beam may be formed from a smaller cross section timber. Typically, one leg will be provided at either end of the ceiling support beam. Depending upon the length of the ceiling support beam, one or more intermediate legs may be provided to prevent the ceiling support beam bowing.

[0011] The insulation support frame may extend from the bottom chord proximal to at least one end of the bottom chord. Particularly, the insulation support frame may be configured so that when in use with the support sections supported by building support structures such as exterior walls, the insulation support frame extends to close to or in touch with the support structures to fill the full width of the building.

[0012] In some examples one end of the bottom chord may be spaced apart from the insulation support frame. This may be suitable for a hybrid building including a modular building unit where the portion of the roof truss not including an insulation support frame flies over the top of the modular building unit (and is supported by an exterior building wall outside of the modular building unit, or the modular building unit itself) and the insulation support frame lies between the modular building unit and another exterior wall of the building. In some cases, the depth of the insulation support frame (defined by the legs and the thickness of the ceiling support beam) is selected so that it matches the depth of ceiling structures within the modular building unit to ensure a uniform ceiling height for rooms within the modular building unit and rooms within the remainder of the building where the insulation support frame is present.

[0013] The top and bottom chords and the insulation support frame may be formed from timber beams. Timber is conventionally used to form roof trusses, however, other materials such as light gauge steel may be used in its place.

[0014] According to a second aspect of the present invention there is provide a building comprising: two spaced apart support structures; and a plurality of roof trusses as defined above; wherein the roof trusses are supported by and span a gap between the two spaced apart support structures to define a roof structure for the building.

[0015] The support structures may comprise building walls, particularly exterior building walls. For the example of a hybrid building comprising at least one modular building unit, one of the support structures may comprises an upper portion of the modular building unit.

[0016] The insulation support frames of the plurality of roof trusses may extend below upper surfaces of the support structures.

[0017] The chords of the roof trusses may be arranged in a spaced apart, parallel formation. At least one of the support structures may comprise a load bearing building wall.

[0018] The insulation support frames of the plurality of roof trusses may be filled with insulation. More precisely, the insulation support frames may align with one another to form a void extending underneath the bottom chords. The undersides of the insulation support frames may be closed off with ceiling material and so define the bottom side of the void and further support insulation material within the void. For instance, a loose fill or rolled insulation material (for instance, rock wool) may be inserted into the void.

[0019] The insulation support frames of the plurality of roof trusses may further support building services including one or more wire, pipe, or duct. That is, building services may be further provided extending through the void defined by the insulation support frames. Where the building includes one or more modular building units, the void defined by the insulation support frames may be used to route services from a modular building unit into the remainder of the building.

[0020] The insulation support frame may be configured such that the depth of filled insulation provides thermal insulation equivalent to the thermal insulation provided by at least one load bearing wall supporting a bottom chord of a roof truss.

[0021] The building may be a hybrid building comprising: a first building section, the first building section being an on-site construction at a final location for the building; and a second building section comprising one or more modular building units, the first and second building sections being configured to be connected at the final location to form the building.

[0022] At least one roof truss may span only the first building section and may be supported by first and second load bearing walls defining the first building section. The insulation support frame may extend the full width of the bottom chord between the first and second load bearing walls.

[0023] At least one roof truss may span both the first building section and the second building section and may be supported either: by first and second load bearing walls defining the first building section; or by a first load bearing wall defining part of the first building section and a modular building unit.

[0024] For each roof truss spanning part of the first building section and part of the second building the insulation support frame may only extend from the bottom chord within the section spanning the first building section.

[0025] The building may further comprise a roof truss without an insulation support frame spanning only the second building section. Such a roof truss may be a conventional roof truss known in the art.

[0026] Within the first building section a ceiling structure may be secured to the underside of the insulation support frame.

[0027] The insulation support frame may be configured such that a ceiling height within the first building section defined by the ceiling structure is the same as a ceiling height within the second building section defined by a modular building unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Examples of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 is a side view of a roof truss according to an embodiment of the invention; Figure 2 is a side view of a roof truss according to another embodiment of the invention; Figure 3 is a cross section view of the roof truss of figure 1 forming part of a hybrid building; Figure 4 is a cross section view of the roof truss of figure 2 forming part of a hybrid building; Figure 5 is a partially cut away perspective view of a hybrid building including roof trusses according to figures 1 and 2; and Figure is an enlarged cross section showing the intersection of part of a roof truss according to figure 1 or figure 2 and a supporting wall. DETAILED DESCRIPTION

[0029] Referring first to figure 1 this illustrates in a side view a roof truss 1 according to a first example of the present invention. The roof truss 1 is shown in a side view, generally in the orientation it would be placed in during construction of a building. The roof truss 1 is formed from timber beams, though other materials may be used where they provide comparable strength and other relevant material properties. The dimensions of the roof truss 1 are context dependent, including taking account of the size of the building, particularly the gap that the roof truss 1 is required to span to form the roof. Furthermore, the dimensions, particularly cross section, of the timber beams forming the roof truss 1 will be dependent on the structural load placed upon the roof truss, particularly the weight of the supported roof structure. The dimensions, geometry (at least in its upper part) and materials forming the roof truss 1 are not germane to the present invention and so will not be further discussed.

[0030] The roof truss 1 comprises a bottom chord 2 (sometimes referred to as a tie beam) configured to bear upon and be supported by two spaced apart support structures. The support structures may be walls, particularly exterior walls, of the building as will be described below. The primary function of the bottom chord 2 is to tie the roof truss 1 together and prevent the weight of the roof displacing the support structures laterally.

[0031] The roof truss 1 further comprises at least one top chord 3 (sometimes referred to as a rafter) connected to the bottom chord 2 and configured to support roofing material on a first (upper) side of the bottom chord 2. In the example of figure 1 the roof truss 1 comprises a pair of top chords 3 forming a double pitched roof shape descending from an apex and connected to either end of the bottom chord 2. The top chords 3 may extend slightly beyond the bottom chord 2 to form a roof overhang. As noted previously, other roof shapes are possible, such as a single pitched roof.

[0032] The roof truss 1 further comprises an insulation support frame 4 extending from the bottom chord 2 on a second (lower) side of the bottom chord 2 opposite the first side. The insulation support frame 4 is configured to support building insulation on the second side of the bottom chord 2. That is, in use, the insulation material frame 4 may be filled with insulation underneath the bottom chord 2 (though optionally insulation may be provided additionally over the top of the bottom chord 2). Where the insulation support frame 4 extends up to one or more support structure such as a building wall, this permits insulation to be provided up to and in contact with the wall to provide unbroken insulation extending from the wall to the ceiling of a room underneath the roof truss 1.

[0033] The bottom chord 2 and top chords 3 are interconnected by webs 5 to brace the chords 2, 3. The bottom chord 2 comprises first and second support sections 6 configured to be supported by the two spaced apart support structures. The support sections 6 may be at or close to each end of the bottom chord 2 and configured in use to be seated upon a top surface of a wall, usually an exterior wall, of a building. More particularly, the support sections 6 may be seated upon and secured to a wall plate. In the example of figure 1 the insulation support frame 4 extends from the bottom chord 2 between the first and second support sections 6 such that in use the insulation support frame 4 comes close to or abuts the building walls. That is, during installation of the roof truss 1 the roof truss 1 is lowered until the support sections 6 contact the top of the wall or the wall plate and the insulation support frame 4 is inserted between upper sections of the walls.

[0034] The insulation support frame 4 comprises a ceiling support beam 7 spaced apart from the bottom chord 2 and a plurality of legs 8 connecting the bottom chord 2 and the ceiling support beam 7. The ceiling support beam 7 extends generally parallel to the bottom chord 2, although this is not essential. In use within a building ceiling material (for instance plasterboard) may be affixed to the underside of the ceiling support beam 7. More particularly, ceiling material will span the undersides of a plurality of insulation support frames 4 forming parts of a plurality of roof trusses 1 defining the shape of the roof. In the example of figure 1 the insulation support frame 4 comprises at least first and second legs 8 located proximal to the ends of the ceiling support beam 7. A third, intermediate leg 8 is also shown, intermediate legs being used where the length of the insulation support frame requires bracing to avoid bowing.

[0035] The insulation support frame 4 defines a void 9. Where a roof is constructed from a plurality of roof trusses 1 the void 9 extends continuously through adjacent roof trusses. The lower side of the void 9 may be further defined ceiling material affixed to the underside of the ceiling support beam 8. Sides of the void 9 at either end of the insulation support frame 4 may be open, though in use closed off by the walls or other structures supporting the support sections 6.

[0036] As noted above, suitably the roof truss 1 including the insulation support frame 4 may be formed from timber. Nodes where the components of the roof truss 1 connect may be connected through nail plates (not illustrated) comprising a metal plate spanning a node through which a plurality of nails or other fixings may be passed into the timber. Roof truss 1 comprises a premanufactured product in that it may be manufactured away from a building site, typically in a factory, and delivered to the building site as a modular building component. Advantageously, this allows for a plurality of roof trusses to be provided that are closely aligned in dimensions. These may be manufactured to fit a specific building under construction. Alternatively, buildings may be designed so that the gap between exterior walls for an uppermost storey of the building matches the spacing between roof truss support sections.

[0037] Referring now to figure 2, a second example of a roof truss 11 is shown. Roof truss 11 is generally similar to roof truss 1 except where noted below and so the same reference numbers are used for corresponding parts, incremented by 10. For roof truss 11 the conventional upper structure comprising bottom chord 12, top chords 13 and webs 15 is the same as for roof truss 1. Furthermore, the bottom chord 12 includes corresponding first and second support sections 16 located at either end close to where the bottom chord 12 intersects the top chords 13.

[0038] Differing from roof truss 1 of figure 1, for roof truss 11 of figure 2 the insulation support frame 14 is shorter. The ceiling support beam 17 extends from proximal to or immediately adjacent to one of the support sections 16 (on the right in figure 2) to only part way along the bottom chord 12. In figure 2 the insulation support frame 14 extends for slightly more than one third of the length of the bottom chord 12, however there is no restriction to the exact proportion of the bottom chord 12 corresponding to the insulation support frame 14. Similarly, the void 19 is shorter than for void 9 of roof truss 1. Figure 2 shows the insulation support frame 14 including only first and second legs 18 at either end of the ceiling support beam 17. However, in some cases one or more intermediate support legs 18 may be provided as for the example of figure 1.

[0039] Roof trusses according to the examples of figures 1 and 2 are suitable for forming the structure of pitched rooves for any type of building. Roof trusses are conventionally used for forming pitched rooves for residential buildings, including detached, semidetached, or terraced houses, however the present invention is not limited to any particular type of building use or configuration. Furthermore, roof trusses according to the present invention may be suitably used for any building construction type, including buildings for which the structure of the building is constructed on-site. There is no limitation to the type of wall structure that is to be used in combination with the roof trusses, so long as it is suitable for supporting the bottom chord at the point on the support section. Indeed, the roof trusses being supported by walls (particularly exterior walls) is the most usual scenario, though other portions of a building may comprise a support structure. As examples, exterior walls where they support roof trusses may be formed from bricks or blocks, cementitious materials (including where this is 3D printed), timber studs, timber panels (including SIPs), light gauge steel studs, or any other known techniques.

[0040] As an alternative to buildings constructed fully on-site (that is, at the building site or final location of the building), prefabricated buildings (also known as ‘modular’ buildings) are well known in the construction industry, particularly modular residential buildings such as houses, flats or apartments, and hotels. Roof trusses according to the present invention may be used to form the roof structure of a modular building. Modular buildings typically comprise a series of modular building units which are constructed in a factory, transported to a final location (or site) for the building, and then arranged in a predetermined configuration and coupled together to form the finished building. The modular building units are typically constructed in the factory to a substantially assembled form in which they can be transported to the final location. Construction of the building can involve stacking one or more upper modular building unit on a lower such unit, so that the upper unit is supported by the lower unit. Modular building units can also be arranged side by side.

[0041] Hybrid buildings have been developed by the applicant which comprise a first building section that is constructed at a final location for the building and a second building section comprising one or more modular building units constructed in a dedicated facility, away from the final location. A hybrid building of this type can provide advantages including that: construction of the first building section is simplified, with more complex parts of the building provided in the section formed by the modular building unit (or multiple modular building units); and the first building section can provide the primary living space in the building, without being constrained by construction and transport limitations imposed on the modular building unit(s). The hybrid buildings and associated construction techniques are disclosed in International patent publication nos. WO2022 / 243696, WO2022 / 243695, WO2022 / 243694, WO2022 / 243693, and WO2023 / 222853.

[0042] The applicant has identified that roof trusses in accordance with figures 1 and 2 may be particularly suited to forming the roof structure of a hybrid building in which the pitched roof extends over both the first and second building sections. An example of this will now be presented in connection with figures 3 to 6.

[0043] In principle the roof trusses may be constructed so that where a roof truss extends between first and second exterior building walls and spans only over the first (onsite constructed) building section, a roof truss 1 according to figure 1 is used so that the insulation support frame 4 extends fully between exterior walls of the building. Elsewhere within the same pitched roof where a roof truss spans both the first building section and the second (modular) building section, a roof truss 11 according to figure 2 is used so that the insulation support frame 14 extends between an exterior building wall defining one side of the first building section and a modular building unit forming part of the second building section.

[0044] Figures 3 and 4 show different cross sections of a hybrid building 30. The cross sections are taken in a vertical plane through the hybrid building and the cross sections are offset from one another along a horizontal axis (extending into the page) so that the cross section of figure 3 shows a roof truss 1 according to figure 1 spanning only a first (on-site constructed) building section 31 while the cross section of figure 4 shows a roof truss 11 according to figure 2 spanning a first building section 31 and a second (modular) building section 40 comprising a modular building unit 41 (shown here as a framework which forms a cuboid shape).

[0045] It can be seen in figure 3 that the support sections 6 of roof truss 1 rest upon wall plates 32 which in turn are secured to the tops of walls 33, walls 33 being the exterior walls of the building. Insulation support frame 4 extends the full width of the building within the first building section 31 between the exterior walls 33 of the building 30. Consequently, thermal insulation can be fitted within the insulation support frame 4 across the full width of the first building section 31 between the exterior walls 33.

[0046] Similarly, figure 4 shows that the support sections 16 of roof truss 11 rest upon wall plates 32 which in turn are secured to the tops of walls 33, walls 33 being the same exterior walls of the building 30 as shown in figure 3, only offset along an axis extending into the page to a point where modular building unit 41 is present. Insulation support frame 14 extends only across the width of the first building section 31 between the right hand exterior wall 33 and the modular building unit 41. Consequently, thermal insulation can be fitted within the insulation support frame 4 across the full width of the first building section 31. Meanwhile, over the second building section 40 the roof truss 11 doesn’t include an insulation support frame. In some cases, the bottom chord 12 passes over the modular building unit 41 without resting upon it. In other cases, the bottom chord 12 may be partially or fully supported by the modular building unit 41 (as well as or instead of the left hand exterior wall 33).

[0047] Meanwhile, the modular building unit 41 includes a ceiling assembly 42 which is relatively deep (optionally this providing space for the installation of building services). As illustrated in figure 4, the insulation support frame 14 of roof truss 11 may be configured (particularly through the construction of the legs) such that it is aligned in depth to the ceiling assembly 42 of modular building unit 41. As such the ceiling height within building rooms in the first and second building sections 31,40 may be same.

[0048] The modular building unit 41, particularly the ceiling assembly 42, may include thermal insulation. In one example the ceiling assembly 42 may including a cavity containing building services such as wires, ducts, and pipes (not illustrated in figure 4) over which is provided a layer of insulation 43, which may suitably be a SIP. A SIP provides a defined degree of thermal insulation. It may be a relatively high degree of insulation per unit thickness. The insulation within void 19 of the insulation support frame 14 may be chosen so that it provides a comparable degree of thermal insulation to that provided within the modular building unit ceiling assembly 42. Owing to the greater depth of the insulation support frame 14 relative to modular building unit insulation layer 43, it may be that a less thermally efficient but cheaper grade of insulation may be used, for instance rock wool. The result is that within rooms defined by the first and second building sections 31,40 a uniform layer of ceiling insulation is provided. Similarly, walls 33 may be formed from an insulating material such as SIPs such that an unbroken and generally similar layer of insulation is provided around and over the rooms in the first and second building sections.

[0049] Turning now to figure 5, this shows in a partially cutaway perspective view hybrid building 30 including the modular building unit 41 in one corner (defining the first building section 40) with the second building section 30 surrounding the modular building unit 41 in an L-shape. Exterior walls 33 are shown on two sides forming spaced apart support structures. A plurality of roof trusses 1 and 11 are shown, selected, and positioned according to whether they span both building sections 31,40 or only the first building section 31. It can be seen in figure 5 how the plurality of roof trusses 1,11 define the shape of the pitched roof. Roofing material (not illustrated) will be applied to the top chords of the roof trusses 1,11 in a convention fashion. The roof trusses are arranged in parallel, spaced apart formation. Insulation support frames 4, 14 extend below the upper surfaces of the walls 33 within the first building section. It will be understood that the bottom chords 2,12, top chords 3, 13 and webs 5, 15 will be connected by timber bracing know as runners extending between the trusses 1, 11. Although not illustrated in figure 5, it will be understood that within the first building section 31 the undersides of the insulation support frames 4, 14 will be boarded out with ceiling material extending up to and typically sealed to the exterior walls 33 and the modular building unit 41 and the void 9, 19 filled within insulation. In some cases, building services including one or more wire, pipe, or duct may also extend within the insulation support frame void 9,19. The building services may also connect through to services within the ceiling assembly 42 of the modular building unit 41. Insulation 43 overlying the modular building unit 41 is also visible in figure 5.

[0050] Figure 6 shows in an enlarged cross section part of roof truss 1 (though equally it may be a roof truss 11) where it engages wall plate 32 of exterior wall 33. Insulation support frame 4, particularly ceiling support beam 7, is shown supporting ceiling material 60, for instance a sheet of plasterboard. Insulation 61 such as rock wool is shown filling void 9.

[0051] Throughout this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other components, integers, or steps. Throughout this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Throughout this specification, the term “about” is used to provide flexibility to a range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint. The degree of flexibility of this term can be dictated by the particular variable and can be determined based on experience and the associated description herein.

[0052] Features, integers, or characteristics described in conjunction with a particular aspect or example of the invention are to be understood to be applicable to any other aspect or example described herein unless incompatible therewith. All of the features disclosed in this specification, and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing examples. The invention extends to any novel feature or combination of features disclosed in this specification. It will also be appreciated that, throughout this specification, language in the general form of “X for Y” (where Y is some action, activity or step and X is some means for carrying out that action, activity or step) encompasses means X adapted or arranged specifically, but not exclusively, to do Y.

[0053] Each feature disclosed in this specification may be replaced by alternative features serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0054] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

:

1. A roof truss comprising:a bottom chord configured to bear upon and be supported by two spaced apart support structures;at least one top chord connected to the bottom chord and configured to support roofing material on a first side of the bottom chord; andan insulation support frame extending from the bottom chord on a second side of the bottom chord opposite the first side;wherein the insulation support frame is configured to support building insulation on the second side of the bottom chord.

2. A roof truss as claimed in claim 1, wherein:the bottom chord has a first end and a second end;the insulation support frame has a first end and a second end;the first end of the insulation support frame is spaced inwardly from the first end of the bottom chord and configured, in use, to extend below an upper surface of a first one of the support structures; andthe second end of the insulation support frame is spaced inwardly from the second end of the bottom chord and configured, in use, to extend below an upper surface of a second one of the support structures.

3. A roof truss as claimed in claim 1, wherein:the bottom chord comprises a first end, and a first support surface extending inwardly from the first end and configured to abut a first one of the support structures;the bottom chord comprises a second end, and a second support surface extending inwardly from the second end and configured to abut a second one of the support structures; andthe insulation support frame has a first end disposed inwardly of the first support surface, and a second end disposed inwardly of the second support surface.

4. A roof truss according to claim 1, wherein the bottom chord comprises first and second support sections configured to be supported by the two spaced apart support structures and the insulation support frame extends from the bottom chord between the first and second support sections.

5. A roof truss according to any preceding claim, wherein the insulation support frame comprises:a ceiling support beam spaced apart from the bottom chord; anda plurality of legs connecting the bottom chord and the ceiling support beam.

6. A roof truss according to claim 5, wherein the ceiling support beam extends generally parallel to the bottom chord.

7. A roof truss according to claim 5 or claim 6, wherein the insulation support frame comprises at least first and second legs located proximal to the ends of the ceiling support beam.

8. A roof truss according to any one of the preceding claims, wherein the insulation support frame extends from the bottom chord proximal to at least one end of the bottom chord.

9. A roof truss according to claim 8, wherein one end of the bottom chord is spaced apart from the insulation support frame.

10. A roof truss according to any one of the preceding claims, wherein the top and bottom chords and the insulation support frame are formed from timber beams.

11. A building comprising:two spaced apart support structures; anda plurality of roof trusses according to any one of the preceding claims;wherein the roof trusses are supported by and span a gap between the two spaced apart support structures to define a roof structure for the building.

12. A building according to claim 11, wherein the insulation support frames of the plurality of roof trusses extend below upper surfaces of the support structures.

13. A building according to claim 11 or claim 12, wherein the chords of the roof trusses are arranged in a spaced apart, parallel formation.

14. A building according to any one of claims 11 to 13, wherein at least one of the support structures comprises a load bearing building wall.

15. A building according to any one of claims 11 to 14, wherein the insulation support frames of the plurality of roof trusses are filled with insulation.

16. A building according to claim 15, wherein the insulation support frames of the plurality of roof trusses further support building services including one or more wire, pipe, or duct.

17. A building according to claim 15 or claim 16, wherein the insulation support frame is configured such that the depth of filled insulation provides thermal insulation equivalent to the thermal insulation provided by at least one load bearing wall supporting a bottom chord of a roof truss.

18. A building according to any one of claims 11 to 17, wherein the building is a hybrid building comprising:a first building section, the first building section being an on-site construction at a final location for the building; anda second building section comprising one or more modular building units, the first and second building sections being configured to be connected at the final location to form the building.

19. A building according to claim 18, wherein at least one roof truss spans only the first building section and is supported by first and second load bearing walls defining the first building section.

20. A building according to claim 18 or claim 19, wherein at least one roof truss spans both the first building section and the second building section and is supported either:by first and second load bearing walls defining the first building section; or by a first load bearing wall defining part of the first building section and a modular building unit.

21. A building according to claim 20, wherein for each roof truss spanning part of the first building section and part of the second building the insulation support frame only extends from the bottom chord within the section spanning the first building section.

22. A building according to any one of claims 18 to 21, further comprising a roof truss without an insulation support frame spanning only the second building section.cm23. A building according to any one of claims 18 to 22, wherein within the first building section a ceiling structure is secured to the underside of the insulation support frame.

24. A building according to claim 23, wherein the insulation support frame is configured5 such that a ceiling height within the first building section defined by the ceiling structure is the same as a ceiling height within the second building section defined by a modular building unit.

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