HK1170785B - Building and method of constructing a building - Google Patents

Description

Building and method of constructing a building

The present invention relates to a building and a method of constructing a building. In particular, but not exclusively, the invention relates to buildings such as houses, schools, offices, hospitals and the like, and to methods of constructing such buildings.

Conventional construction methods have a number of problems. One problem is that it is very difficult to construct buildings with a very high degree of thermal insulation using many construction methods. Thermal insulation is typically provided by inserting an insulating material in the cavity between the inner and outer layers of the wall. Such materials may be added during construction of the building, for example by inserting solid blocks of insulating material into cavities between the inner and outer walls when the walls are being constructed. Alternatively, the insulation material, for example in the form of foam, may be poured into the cavity between the inner and outer walls after the walls have been built.

Different methods can be used for insulating the roof space: for example, a fiber-woven blanket may be placed between ceiling rafters in the roof space. However, these conventional insulation methods often result in gaps being left around the building in various places, such as around eaves and under floor space. These gaps allow thermal bridging to occur and allow air to flow into and out of the building, thereby allowing heat to escape.

Another problem with many conventional construction methods is that the construction costs are high. For example, for a conventional house with brick or stone walls, deep trenches must be dug and concrete foundations laid to support the weight of the walls. This is both time consuming and expensive. Another problem with many conventional buildings is that the methods of constructing them are very labor intensive, such as bricking. This also increases the construction cost.

A further problem with this approach is that the physical wall structure makes inspection of the building during construction very difficult, since many structural elements will be hidden during construction. This makes it difficult to confirm whether the building complies with the building regulations and a good building process.

It is an object of the present invention to provide a building and a method of constructing a building which reduces one or more of the above disadvantages.

According to the present invention there is provided a method of constructing a building comprising a plurality of walls, a roof and a floor, the method comprising erecting a plurality of truss elements to form a framework comprising at least two opposed wall formations, a roof formation and a floor formation, each said construction comprising a plurality of truss elements, each truss element comprising at least two joists and a plurality of braces maintaining the parallel arrangement of the joists, each said truss element being arranged within the framework to have inner and outer joists; attaching an inner cover layer and an outer cover layer to the frame to form an enclosed cavity substantially continuously through the floor structure, roof structure and opposing wall structure between the inner and outer cover layers, injecting an insulating material into the cavity to form an insulating layer substantially continuously through the floor structure, roof structure and opposing wall structure between the inner and outer layers.

The method allows buildings to be constructed relatively easily and at little or no additional cost relative to buildings of conventional construction, yet at very high levels of thermal insulation, for example, having a U value (heat transfer coefficient) of less than 0.15W/m for roofs, floors and exterior walls²K and possibly as small as 0.05W/m²K. This far exceeds the level of thermal insulation of conventional construction methods without incurring appreciable additional costs. This very high level of thermal insulation is achieved because the insulation layer extends substantially continuously and seamlessly around the entire perimeter of the building (including the roof structure, walls and floor) and seals all gaps within the structure, thus avoiding thermal bridges and preventing air leakage.

The construction method is easy to implement, only requires basic construction skills and reduces the requirements of expensive plants and equipment. This renders it beneficial for the improvement of the safety of the construction site. The construction method is also well suited for rapid construction of buildings in emergency situations, for example, when after an earthquake or other disaster, skilled workers and expensive construction equipment may be in short supply. In this case, the building may be constructed from locally available materials or from prefabricated components.

The structure of the building is very light and strong due to the direct connection between the truss elements forming the walls, floor and roof. The building does not require a deep or continuous foundation and is capable of withstanding strong external forces, such as those caused by earthquakes, hurricanes, and other causes.

Furthermore, buildings constructed using the method according to the invention have an open frame that can be easily inspected during construction, allowing surveyors and building inspectors to confirm that the building meets all building standards and regulations.

Advantageously, at least some of the truss elements forming the floor structure, roof structure and opposing wall structure are interconnected end to form a substantially continuous framework extending through the floor structure, roof structure and at least one wall structure.

Preferably, the interconnected truss elements forming each substantially continuous frame lie in a common vertical plane.

Preferably, the inner joists of the interconnected truss elements are interconnected and the outer joists of the interconnected truss elements are interconnected.

Preferably, the method includes erecting a plurality of truss elements to form at least one end wall construction and installing an inner and outer covering on the end wall construction to form an end wall cavity connected to a cavity extending through the floor construction, roof construction and opposed wall constructions.

Advantageously, the inner and outer layers forming the cavity are spaced apart by a distance in the range 50-600mm, preferably 200-450 mm. We have found that such spacing with existing insulation materials provides the best balance of insulation thickness and construction cost.

Preferably, the frame is supported on separate piles or foundation pads. Construction costs are reduced by avoiding the need to excavate conventional foundations. Because the structure of buildings is very light but strong, simple piles or foundations have been found to provide adequate support.

The moisture barrier may be mounted under a floor structure. Advantageously, the moisture barrier extends at least partially up to the walls of the building, preferably to a height of at least 150mm above ground level. When flood protection is required, the membrane may be extended to a higher height. This provides a very high level of flood protection (especially when the building is also fitted with watertight doors and windows).

The insulation layer of the roof structure may be disposed within the ceiling structure, such as below an attic space. Alternatively, the insulation of the roof construction may also be provided within the inclined roof construction, above the attic space.

Advantageously, the method comprises applying an exterior finish to the exterior cladding of at least one wall and/or roof structure. Preferably, the outer modification layer comprises an insulating layer.

According to another aspect of the present invention there is provided a building having a plurality of walls, a roof and a floor, forming a plurality of truss elements including at least two opposed wall formations, a roof formation and a floor formation, each said formation including a plurality of truss elements and each truss element including at least two joists and a plurality of braces maintaining the joists in a parallel arrangement, each said truss element being arranged within the framework to have inner and outer joists; an inner cover layer and an outer cover layer attached to the frame and providing a closed cavity substantially continuously through the floor structure, roof structure and opposing wall structure between the inner and outer cover layers; an insulating material for injecting the cavity and forming an insulating layer between the inner and outer layers, wherein the insulating layer extends substantially continuously through the floor structure, the roof structure and the opposing wall structure.

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

FIG.1 depicts a set of trusses suitable for constructing a building, in this example a simple two-storey house;

FIG.2 is a perspective view showing the layout of the trusses forming the bottom floor of the house;

FIG.3 is a perspective view showing the layout of the trusses forming the upper floor of the house;

FIG.4 is a perspective view showing the layout of a truss forming a ceiling of a house;

FIG.5 is a perspective view showing the layout of the trusses forming the front wall of the house;

fig.6 is a perspective view showing the layout of trusses forming the back wall of a house;

FIG.7 is a perspective view showing the layout of the trusses forming the right hand side wall of the house;

FIG.8 is a perspective view showing the layout of the trusses forming the left hand side wall of the house;

FIG.9 is a perspective view showing the complete frame of the house;

FIG.10 is an exploded perspective view showing the complete frame of the house;

figure 11 is an exploded view illustrating a skeletal structure of a house including a roof structure,

FIG.12 is a perspective view showing the complete skeletal structure of the house;

fig.13 and 14 are perspective views illustrating a truss attachment method;

FIG.15 is a perspective view showing the complete skeletal structural detail;

FIG.16 is a perspective view showing details of the foundation construction;

FIG.17 is a sectional view showing perspective details of the underlying flooring construction;

figure 18 illustrates a series of connection steps of a method of building construction,

FIGS. 19 and 20 are cross-sectional views of two complete houses with a convertible arrangement for insulating the roof construction;

figure 21 is an isometric view of a scaffolding clamp,

FIG.22 is an isometric view of the plate spacing and securing tool.

Figure 1 shows a set of trusses 2 which are applied in a method of construction to construct a building, in this case a simple two-storey house. In this example, ten types of girders 2 are shown, differing in length and referred to as types T1-T10. Each truss 2 comprises two parallel elongated members or joists 4, which are preferably made of wood but may alternatively be made of other materials (e.g. steel, concrete, etc.). The two joists are interconnected by a series of braces 6, which braces 6 may be made of, for example, galvanized steel, and maintain a constant spacing between the joists.

In some trusses (e.g. types T1-T4, T6 and T9-T10) the two joists 4 are of equal length and their ends are connected by a cross-brace 8. In other trusses (e.g. types T5, T7 and T8), one joist is slightly longer and includes a portion 4' extending beyond the end of the other joist at one or both ends. In types T7 and T8, a wale 8 is provided adjacent each end of the joist to support the extension 4'.

In the present construction method, a large number of various types of trusses are applied. These trusses are preferably made to a standard gauge with a constant spacing between the inner surfaces of the joists. For example, each individual joist may have dimensions of 75 x 47mm and the spacing between their inner surfaces is set to 206mm, so the width between the outer surfaces of the joists is set to 300 mm. Although a width in the range of 50-600mm between the outer surfaces of the joists is generally preferred, and 200-450mm is most preferred, other dimensions are of course possible. The length of each truss may vary depending on the type of truss and the desired location of the truss within the building. Typically up to about 10 meters in length.

When a building is constructed, the type and number of trusses required to construct the building frame are first calculated and then the trusses are manufactured and identified. Typically, the trusses will be pre-manufactured and identified off-site before being shipped to the construction site. Alternatively, they may be manufactured in situ. These trusses are then assembled in a predetermined order during the building construction process.

The layout of the trusses and other elements required to build a simple two-storey house is shown in figures 2-17. It should be understood that these figures illustrate only a single example of a typical building constructed according to the methods disclosed herein: the number and layout of trusses may vary when constructing other buildings.

In this example, the framework of the underlying floor 10 is constructed from fourteen trusses of type T7, each truss having a shorter upper joist and a longer lower joist. The trusses are arranged parallel to each other, as shown in fig.2, mostly at a spacing of 600mm from center to center, with a spacing of 300mm between the three trusses closest to the front of the building and the two trusses closest to the back of the building.

The framework of the upper floor 12 is constructed of eight T9 type and five T10 type trusses, each having upper and lower joists of the same length. As shown in fig.3, the trusses 2 are arranged parallel to each other at a certain interval. The shorter T10 type truss is provided with an opening 14 for a staircase. The frame is completed by a ring beam 16 extending around the periphery of the frame and a trim member 18 extending laterally along the end of the shorter T10 type truss adjacent the stair opening 14.

The framework of the ceiling structure 20 is constructed from fourteen T8 type trusses, each having one longer joist and one shorter joist. As shown in fig.4, the joists 2 are arranged parallel to each other, mostly at a spacing (centre-to-centre) of 600mm, with a spacing of 300mm between the three trusses closest to the front of the building and the two trusses closest to the back of the building.

The framework of the front wall 20 is constructed of trusses of the types T1, T2, T3, T4 and T6 as shown in fig. 5. Nine trusses of the T6 type are arranged vertically to form the primary structure of the wall, while the other trusses are installed either vertically or horizontally to build up 3 window openings 24 and one door opening 26. The frame of the back wall 28 shown in fig.6 is of similar construction, including T3, T4 and T6 type trusses arranged to provide openings for two upper windows 30 and two lower windows or doors 32.

The right and left side walls 36, 38 are shown in fig.7 and 8 and each consist of fourteen T5 type trusses each having an inner joist with a shorter upper end and a longer outer joist. These joists 2 are arranged vertically, mostly at a spacing (centre-to-centre) of 600mm, with a spacing of 300mm between the three trusses closest to the front of the building and the two trusses closest to the back of the building, to match the trusses forming the underlying floor and ceiling.

Figures 9 and 10 show the complete building frame including the sub-floor 10, the upper floor 12 and the ceiling structure 20 and the front 22, rear 28 and side walls 36, 38. The trusses forming the subfloor 10, the opposed side walls 36, 38 and the ceiling structure 20 are connected end to form a fourteen rectangular frame structure, each extending continuously around the building. The frames of the front and back walls 22, 28 are supported by the trusses of the floor structure and are directly connected to the frames of the underlying floor 10, ceiling structure 20 and side walls 36, 38. This gives the complete building frame high strength and rigidity.

It is noted that the outer joists of the opposing side walls 36, 38 are connected to the outer joists of the subfloor 10 and the ceiling structure 20 (i.e., the lower joists of the subfloor and the upper joists of the ceiling structure), while the inner joists of the side walls are connected to the inner joists of the subfloor and the ceiling structure. The ends of the joists are connected by, for example, metal bolster plates or screws. The inner and outer joists of the front and back walls 22, 28 are similarly connected with respect to the inner and outer joists of the underlying floor 10 and ceiling structure 20.

When the inner and outer surfaces of the frame are covered with panels, the structure provides a cavity 40 that extends continuously around the four outer walls 22, 28, 36, 38, the subfloor 10 and the ceiling structure. The cavity 40 is then filled with a thermally insulating material to provide an insulating layer that extends continuously and seamlessly around all of the exterior sides of the building.

The upper and lower joists of the superstructure 12 also include a cavity therebetween, but in this embodiment the cavity of the superstructure is separated from the cavity of the surrounding wall by a ring beam 16 connected to the joists in the wall. Thus, when the insulating material is injected into the wall, it does not flow into the cavity of the upper floor: in this position it is not necessary, since the upper floor 12 does not form the exterior surface of the building. However, if it is desired to form insulation within the superstructure, such as to reduce heat flow within the building, this can be achieved by providing a number of apertures in the ring beam 16 so that the insulation can flow into the superstructure cavity.

Fig.11 and 12 show a complete building construction skeleton, comprising, in addition to the frame of fig.9 and 10, a foundation 42, a moisture barrier (DPC) 44, stairways 46 and a roof construction 50. In this case, the roof construction 50 is formed from a series of conventional roof trusses 52 to form an attic space between the ceiling construction and the pitched roof. Many other roof constructions may be used, including pitched, flat and pitched roof constructions.

Alternatively, the pitched roof construction shown in fig.19 may employ trusses of the type used in the construction of walls and floor structures, which roof construction may be connected to the walls in a similar manner as described above for connection to the ceiling structure, such that the cavity in the roof structure is continuously connected with the cavity in the walls. Then, when the insulation material is injected, it will form an insulation layer that extends continuously around all exterior sides of the building, including the roof construction. In this case, a conventional ceiling construction may be provided if desired. The insulation will be located above the ceiling structure and attic space.

Further details of the building construction are shown in figures 13 to 17. Figures 13 and 14 show details of the method of joining the ends of the trusses forming the sub-floor 10, side walls 38 and ceiling construction 20 and also the superstructure 12. The outer joists of the subfloor and ceiling trusses and the outer joists of each wall truss are extended at their upper ends so that they can be connected to each other. The inner joists are similarly interconnected. The joists are fixed to each other using, for example, bolster plates and screws. The sub-floor joists are secured to the foundation 42 using, for example, anchor bolts (not shown). The joists of the upper floor structure 12 are connected to ring beams 16 which are attached to the inner joists of the wall truss. The roof truss 52 is attached to the truss of the ceiling structure 20 using a joist board.

Figure 15 shows a detail of the interior panelling applied to the frame. The frame of the sub-floor 10 is covered with a floor 54 comprising a layer of 18mm Oriented Strand Board (OSB) and a layer of 50mm Expanded Polystyrene (EPS) insulation board and finished with a 22mm layer of oriented strand board. The inner surface of the wall 38 is covered by 18mm oriented strand board and the frame of the upper floor 12 is covered by 22mm oriented strand board layers. The ceiling was covered with 18mm oriented strand board.

The details of the foundation are shown in figure 16. The building is supported on concrete ground beams 56 which are secured to the buried concrete piles 42 by bolts 55. This is usually sufficient because buildings have a low weight. If larger and heavier buildings are constructed, more foundations or piles may be required.

Details of the structure of the completed building are shown in cross-section in figure 17. The framework consisting of the trusses 2, including the subfloor construction 10, walls 22, 28, 36, 38 and roof construction 50, is completely covered by an inner cover 57 and an outer cover 58 to form a void 40 extending around the exterior surface of the building. Various panels may be used to form the inner and outer coverings, except where the outer covering of the floor structure is formed of a moisture barrier film (DPM) 62 placed below the floor.

The ground beneath the ground truss 10 is covered with a 75mm layer of sand/cement screed 59 over a 100mm layer of tamped stone filler 60. The moisture barrier 62 is placed over the screed and extends outwardly between the side walls 38 and the ground beam 56. The edges of the moisture barrier film 62 are folded up to cover the bottom of the wall construction 38, typically having a height of 500 mm. The outer surface of the wall construction is covered by a layer of 18mm oriented strand board 64 (the bottom of which is covered by a moisture barrier film), then a layer of 60mm expanded polystyrene insulation board 66, and finally finished by a selected plaster facing 68. The lowermost portion of the wall is protected by a molded moisture barrier 70 which is secured over battens 72 which secure the moisture barrier over the vertical oriented strand board. The inner surface of the wall construction is covered by a layer of 18mm oriented strand board 73.

The method of constructing a building is illustrated in figure 18. In this example, the building is a house. It should be understood that the method may also be applied to the construction of other buildings.

Step 1 illustrates the early stages of construction. The overburden has been removed from the building site leaving a shallow pit 77 covering the surface area of the building. A series of foundation holes 76 are dug. In step 2, concrete is poured into the holes to form a series of concrete foundation pads 78. These two steps of the construction method are conventional and will not be described further.

Concrete ground beams 56 are then placed across the foundation pad 78 to form the foundation structure of the building (step 3). The area between the beams is then filled with stone filler 60 and covered with concrete/sand screed 59 (steps 4-5). Scaffolding 80 is then erected around the building site (step 6): the scaffolding erected in front of the building (step 7) is omitted for clarity. A moisture barrier (DPM) 62 is placed across the beam 56 and the screed 58. Alternatively, if flooring ventilation is required, the screed layer may be omitted: the moisture barrier 62 is then simply placed across the beam 56.

To build the underlying floor 10, a predetermined number of pre-assembled trusses 2 are placed across the beams 56 so that they extend across the width of the building at right angles to the beams (step 8). The trusses 2 are arranged laterally with respect to the beams 56 such that one joist within each truss is placed at a higher elevation than the other. The upper joist forms an upper part of the ground construction and the lower joist forms a lower part of the ground construction.

The exact spacing between the girders 2 can be ensured by applying a comb template (not shown) having a plurality of recesses receiving the ends of the girders. After the truss is secured in place, the form may be removed. Alternatively, the spacing may be set by fixing pre-cut timber spacing elements between the trusses. The trusses are arranged so that they lie parallel to one another, typically with a spacing of 600mm on center (although the spacing may be in the range of 100 and 800mm, for example).

After placing the truss forming the floor 10, a sub-floor 54 of 18mm oriented strand board is placed to provide an accessible work surface (step 9). The next step is to erect another series of trusses to form the side walls 38 of the building (step 10). Also, the trusses 2 of the wall are typically pre-assembled and coded in preparation for erection. Each of the wall trusses 2 is connected to an end of one of the floor trusses, thereby ensuring accurate spacing between the wall trusses. The wall truss is arranged vertically with one joist on the inside of the wall and the other joist on the outside of the wall. The exact spacing between the upper ends of the vertical girders 2 is ensured by clamping the girders by scaffold clamps 82 previously attached to the scaffolds. This process is repeated while erecting the truss of the other side wall 36 (step 11).

Although not shown in the figures, slats may alternatively be temporarily attached to the vertical trusses to hold them in place.

After erecting the vertical trusses forming the side wall 36, 38 construction, the next stage is to attach ring beams 16 on the side walls and assemble the upper floor construction 12 by attaching horizontal trusses on the ring beams (step 12). If desired, stair joists may also be attached at this stage. The upper floor 84 of 22mm oriented strand board was then placed on the upper floor truss (step 13).

The next stage is to attach more pre-assembled trusses to form the ceiling construction 20 (step 14). Horizontal trusses are attached to the upper ends of the vertical trusses of the opposite side walls to form the ceiling structure 20. The exact spacing between the ceiling trusses is ensured by attaching them to the previously erected side wall trusses.

The trusses forming the back wall 24 are then inserted and connected with the trusses of the floor structure 10, ceiling structure 20 and side walls 36, 38 (step 15). The trusses forming the front wall 22 are assembled in a similar manner (step 16).

The next step is to apply an outer facing over the frame (step 17). The outer facing typically comprises a layer of 18mm oriented strand board attached to the outer surface of the frame to cover the front, back and side walls. Oriented strand board ensures that the truss is in place so that the building can be self-supporting. The floor structure is connected to the foundation 10 above the moisture barrier and is connected to the load bearing walls through the oriented strand board surround, thus holding the building in place. The moisture barrier 62 is trimmed and secured to cover the lower portion of the outer facing 64. A hard outer moisture barrier 70 is then attached to all exposed facades (step 18).

Thus completing the construction of the basic frame of the building. This is certainly true at this stage, where the interior of the frame is completely open, as it allows easy inspection of all elements of the construction to comply with building codes. Although not shown in the figures, supply facilities (e.g. electricity and water) or pipes for these supply facilities may also be installed on the frame at this stage.

The roof trusses 52 are then positioned and secured in place (step 19). An inner facing 57 is attached to the inner surface of the frame and an outer facing 58 is attached to the outer surface of the frame, covering the walls and ceiling (step 20). Any suitable material may be used, for example plasterboard or fire retardant panels for wall and roof construction, oriented strand board for flooring, recycled cardboard or flooring. Doors and windows are also inserted.

This completes the main construction of the building. It is noted that the void 40 between the inner and outer claddings of the frame is completely open. The cavity extends substantially continuously around the frame of the building including the walls, floor and roof construction. In this context, the term "roof construction" includes ceiling constructions and external roofs, since one of these constructions may be provided with cavities which are subsequently filled with an insulating material.

The cavity 40 in the wall, floor and roof construction is then filled by pumping a suitable insulating material under pressure into the cavity. Any suitable insulating material may be used, for example expanded or expanded polystyrene particles. The insulating material 86 completely fills the void and provides a substantially continuous layer of insulation throughout the wall, floor and roof construction of the building and fills all gaps in the framing panels.

Finally, interior finishing of the building may be accomplished, and exterior walls and roofs may be covered with insulation and exterior finishing layers, including, for example, render or brick, cladding, roof shingles, and the like.

In the embodiment shown in fig.19, the pitched roof construction 50 is formed from a series of conventional roof trusses 88 forming an attic space 90 between the ceiling construction 20 and the pitched roof. The ceiling structure 20 is comprised of trusses of the type shown in fig.1 to provide a cavity that connects with the cavities of the walls 36, 38. When injected, the insulating material forms an insulating layer 86 that extends continuously around all of the exterior sides of the building, including the walls 36, 38 and the floor 10 and roof structure 50. The insulation of the roof structure is located within the ceiling structure below the attic space 90.

An alternative arrangement is shown in figure 20, in which a pitched roof construction 50 is formed from trusses of the type shown in figure 1. This roof structure 50 is attached to the walls 36, 38 such that the cavity of the roof structure is continuously connected with the cavity of the walls. When the insulating material is injected, it forms an insulating layer that extends continuously around all of the exterior sides of the building including the walls 36, 38 and the floor 10 and the rooftop construction 50. In this case, the cavity of the ceiling structure 20 is not connected to the cavity of the wall and is not filled with an insulating material. An insulating layer 86 is located above the ceiling structure 20 and the attic space 90.

A scaffold clamp 82 for use in erecting a building frame is shown in figure 21. The clip includes a plate 92 having a releasable locking element 94 which together form a circular aperture 96 to receive a horizontal scaffold bar. Attached to the plate 92 are two U-shaped support members 98, each of which includes a base portion 100 and two parallel arms 102. Screw holes 104 are provided in the base portion 100.

In use, the scaffolding clips 82 are connected to the horizontal scaffolding legs of scaffolding erected about a building site at appropriate intervals such that the support elements 98 are disposed one vertically above the other. The upper end of each vertical truss 2 is then positioned between the two arms 102 of the support member 98 and secured by screwing screws through screw holes 104 into the truss, as shown in step 10 of fig. 18. This ensures accurate spacing between the trusses and their proper location when building the rest of the frame. Once the frame is complete, the scaffold clamp 82 is removed.

Spacing and securing means 106 applied in joining the outer insulation and cladding panels 66, 68 shown in fig.17 are shown in fig. 22. The tool includes a horizontal base plate 108, a back plate 110 extending upwardly from the back edge of the base plate 108, and a front plate 112 extending downwardly from the base plate 108 adjacent its front edge. The flange plate 114 extends diagonally between the base plate 108 and the front plate 112.

In use, when the outer insulation and cladding panels 66, 68 are secured to the building frame, as shown in fig.17, spacing and securing means 106 are used to temporarily support the sheets and provide a spacing of approximately 5mm between the edges of adjacent sheets to allow the sheets to expand and contract. Once the sheet material is secured in place, the tool 106 is removed.

Claims (20)

1. A method of constructing a building comprising a plurality of walls, a roof and a floor, the method comprising:

erecting a plurality of truss elements to form a framework comprising at least two opposed wall formations, a roof formation and a floor formation, each said formation comprising a plurality of truss elements, each truss element comprising at least two joists and a plurality of braces maintaining the joists in a parallel arrangement, each said truss element being arranged within said framework to have inner and outer joists;

attaching an inner cover layer and an outer cover layer to the frame, thereby forming voids within the floor structure, roof structure and opposing wall structure, the voids communicating with each other to form an enclosed void between the inner and outer cover layers that extends substantially continuously through the floor structure, roof structure and opposing wall structure, and

after forming the enclosed void, injecting an insulating material into the void to fill the void and form an insulating layer between the inner and outer layers that substantially continuously and seamlessly penetrates the floor structure, roof structure, and opposing wall structure.

2. A method according to claim 1, wherein at least some of the truss elements forming the floor, roof and opposing wall constructions are interconnected end to form a substantially continuous framework extending through the floor, roof and at least one wall construction.

3. The method of claim 2, wherein the interconnected truss elements forming each of the substantially continuous frames lie in a common vertical plane.

4. The method of claim 2, wherein the inner joists of the interconnected truss elements are interconnected and the outer joists of the interconnected truss elements are interconnected.

5. A method according to any one of claims 1 to 4, including erecting a plurality of truss elements to form at least one end wall formation and attaching inner and outer cover layers to the end wall formation to form an end wall cavity which connects with the cavity through the floor formation, roof formation and opposed wall formation.

6. A method according to any one of claims 1 to 4, wherein the inner and outer layers forming the void have a spacing therebetween in the range 50-600 mm.

7. A method according to any one of claims 1 to 4, wherein the frame is supported on separate piles or foundation mats.

8. A method according to any one of claims 1 to 4 wherein a moisture barrier is mounted beneath the floor structure and is selectively extendable at least partially up the walls of the building.

9. A method according to any of claims 1 to 4, wherein the insulation layer of the roof construction is provided within a ceiling construction or within an inclined roof construction.

10. A method according to any one of claims 1 to 4, including applying an outer finishing layer to an outer covering layer of at least one of the walls and/or roof constructions.

11. A building comprising a plurality of walls, a roof and a floor, a plurality of truss elements forming a framework including at least two opposed wall formations, a roof formation and a floor formation, each said formation including a plurality of truss elements, each truss element including at least two joists and a plurality of braces maintaining the joists in a parallel arrangement, each said truss element being arranged within said framework to have inner and outer joists;

an inner cover layer and an outer cover layer attached to the frame, cavities being formed in the floor structure, roof structure and opposing wall structure, the cavities communicating with each other to form an enclosed cavity between the inner and outer cover layers that extends substantially continuously through the floor structure, roof structure and opposing wall structure, and

an insulating material for injecting the holes and forming an insulating layer between the inner and outer layers,

wherein the insulating layer is substantially continuous and seamless throughout the floor construction, roof construction and opposing wall construction.

12. A building according to claim 11, in which at least some of the truss elements forming the floor, roof and opposed wall formations are mutually connected end to form a substantially continuous framework throughout the floor, roof and at least one wall formation.

13. A building according to claim 12 wherein the interconnected truss elements forming each of the substantially continuous frames lie in a common vertical plane.

14. A building according to claim 12 wherein the inner joists of the interconnected truss elements are interconnected and the outer joists of the interconnected truss elements are interconnected.

15. A building according to any one of claims 11 to 14, including at least one end wall construction comprising a plurality of truss elements, an inner covering and an outer covering, the end wall construction including an end wall cavity connected with a cavity through the floor construction, roof construction and opposed wall construction.

16. A building according to any one of claims 11 to 14, in which the inner and outer skins have a spacing therebetween in the range 50-600 mm.

17. A building according to any one of claims 11 to 14, in which the frame is supported on separate piles or foundations.

18. A building according to any one of claims 11 to 14, including a moisture barrier beneath the floor structure, the moisture barrier being selectively extendable at least partially up a wall of the building.

19. A building according to any one of claims 11 to 14, in which the insulation within the roof construction is provided within a ceiling construction or within an inclined roof construction.

20. A building according to any one of claims 11 to 14, including an outer finishing layer attached to an outer covering of at least one of the walls and/or roof constructions.