Building system

Abstract

The disclosure provides a building system and a method of building a structure incorporating the building system. The building system includes a floor panel and at least one composite wall panel which extends generally vertically at an edge of the floor panel. The composite wall panel includes a cross-laminated timber (CLT) panel with a weatherproof panel directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel.

Description

[0001] BUILDING SYSTEM

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority from South African patent application number 2024 / 06471 filed on 23 August 2024, which is incorporated by reference herein.

[0004] FIELD

[0005] This disclosure relates to a building system, a kit for a building system and a composite wall panel for a building system. The building system may be suitable for a prefabricated building to be installed on-site.

[0006] BACKGROUND

[0007] The supply and availability of low-cost housing that is quick to build and cost-effective is vital to compensate for a growing need of housing and localised building solutions. Traditional brick and mortar buildings are sturdy but are not cost or time efficient to meet the growing needs of society. When designing for large-scale deployment of housing, there are multiple factors that need to be considered.

[0008] The ever-present risk of climate change and resource depletion weighs heavily on the choice of building materials when considering both cost and the volume of resources that may be required. Using renewable bio-based resources for building materials may both reduce the risk to the climate, while allowing the building material to be replenished to meet the ever-increasing housing demand.

[0009] The use of prefabrication methods in a manufacturing facility allows for careful construction to ensure a high-level of quality while allowing for modularity and for production to be ramped up at scale. Prefabrication of construction components may also allow for more complex components to be produced cost-effectively by using a purpose-built manufacturing facility. Prefabrication allows for on-site installation and fast construction after manufacturing of the necessary construction components.

[0010] The added benefits of using prefabricated components in the construction of housing or building units is only beneficial if suitable building materials are used and the prefabricated components are suitably designed around the chosen material. This may require non-standard manufacturing and on-site construction techniques to take advantage of the potential benefits. However, few designs of building system components take advantage of the potential benefits that prefabrication allows.

[0011] There is accordingly scope for improvement.

[0012] The preceding discussion of the background is intended only to facilitate an understanding of the present disclosure. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application.

[0013] SUMMARY

[0014] In accordance with an aspect of the disclosure there is provided a building system comprising: a floor panel; and at least one composite wall panel which extends generally vertically at an edge of the floor panel; wherein the composite wall panel includes a cross-laminated timber (CLT) panel with a weatherproof panel directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel.

[0015] The weatherproof panel may be directly fixed to the CLT panel across substantially an entire surface of the weatherproof panel so that substantially no void exists between the weatherproof panel and the CLT panel. To accomplish this, the weatherproof panel may be directly fixed to the CLT panel by an adhesive or sealant, such as an expanding polyurethane adhesive. The weatherproof panel may optionally be further reinforced by means of pins or nails driven through the weatherproof panel into the CLT panel. In one example, the pins or nails may be brad nails such as rapid small head brad nails, which can be driven in by a pneumatic nail gun.

[0016] The weatherproof panel may be a fibre cement panel.

[0017] A second weatherproof panel may be provided and fixed to a lowermost, exposed section of the CLT panel to form a skirt which completes weatherproofing of the external face of the composite wall panel and which extends below a level of an underside of the floor panel. The skirt may form a drip edge for water running down the external face of the composite wall panel.

[0018] The building system may include a sub-frame to support the floor panel, with the sub-frame being set back from at least one edge of the floor panel.

[0019] The sub-frame may be made from glue-laminated timber beams joined together in a structural framework.

[0020] The building system may include a channel formed between the skirt and the sub-frame, the channel being at least partially shielded from view by the skirt, and the channel may accommodate conduits or other services.

[0021] The channel may accommodate one or more of: water pipes, electrical cabling, trunking, conduits, and lighting.

[0022] The floor panel may be generally rectangular in plan view, and composite wall panels may extend on each of four edges of the floor panels, with the composite wall panels joined together at right angles at four corners of the floor panels.

[0023] The composite wall panels may be joined at the four corners by butt joints.

[0024] The building system may include a ring beam comprising four beam sections joined together extends atop the composite wall panels and supports a roof structure.

[0025] The ring beam may be made from CLT and external faces of the ring beam may have weatherproof panels directly fixed to them.

[0026] Two or more composite wall panels of the building system may extend side by side at the edge of the floor panel, the composite wall panels being joined together by joints. The joints may be butt joints or lap joints.

[0027] The joints may include a gap at external-facing sides of the composite wall panels, and backing cord may be provided within the gap and covered by a sealant to form a flush outer finish. The sub-frame may be supported by a micro-pile footing system, the micro-pile footing system including at least one bracket which supports multiple piles to be driven into the ground at different angles to each other, the bracket including a levelling and connection plate to the sub-frame.

[0028] The sub-frame may be generally rectangular in plan view, and the micro-pile footing system may include one bracket towards each corner of the sub-frame, as well as at least one bracket between two corners of the sub-frame that supports splayed piles to be driven into the ground for additional lateral stability.

[0029] The building system may include a window aperture in the composite wall panel and a window mounted within the composite wall panel.

[0030] The building system may include pre-drilled conduits and plug sockets within the composite wall panel.

[0031] The building system may include electrical conduits and plumbing pipes within the pre-drilled conduits.

[0032] An internal face of the composite wall panel may include polyvinyl chloride (PVC) or vinyl sheeting directly fixed to the CLT panel to form a sealed waterproof wall.

[0033] In accordance with an aspect of the disclosure there is provided a kit for a building system, the kit including a prefabricated floor panel and at least one prefabricated composite wall panel that includes a cross-laminated timber (CLT) panel with weatherproof panel directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel.

[0034] The kit may include a second weatherproof panel sized to be fixed to a lowermost, exposed section of the CLT panel to form a skirt which completes weatherproofing of the external face of the composite wall panel and which extends below a level of an underside of the floor panel.

[0035] In accordance with an aspect of the disclosure there is provided a composite wall panel for a building system, comprising a cross-laminated timber (CLT) panel with a weatherproof panel directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel.

[0036] In accordance with an aspect of the disclosure there is provided a method of building a structure comprising: providing a prefabricated floor; providing a prefabricated composite wall panel which includes a cross-laminated timber (CLT) panel with a weatherproof panel directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel; mounting the composite wall panel generally vertically at the edge of the floor with the weatherproof external face being outward facing.

[0037] The method may include, once the composite wall panel is mounted to the floor, fixing a second weatherproof panel to a lowermost, exposed section of the CLT panel to form a skirt which completes weatherproofing of the external face of the composite wall panel and which extends below a level of an underside of the floor panel.

[0038] Embodiments of the technology will now be described, by way of example only, with reference to the accompanying drawings.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In the drawings:

[0041] Figure 1A is an exemplary illustration of a building unit constructed using a building system;

[0042] Figure 1B is an exemplary illustration of a corner portion of the building unit;

[0043] Figure 2 is an exemplary illustration of a sub-frame framework structure;

[0044] Figure 3A is an illustration of an example micro-pile footing, including a levelling and connection plate;

[0045] Figure 3B is an illustration of an example micro-pile footing with piles attached to a subframe;

[0046] Figure 4A is an exemplary illustration of a cross-sectional side view of the building system;

[0047] Figure 4B is an exemplary illustration of a cross-sectional side view of the building system showing internal wall panel components; Figure 5A is an exemplary illustration of internal components of a lower portion of a wall panel, floor and sub-frame;

[0048] Figure 5B is an exemplary illustration of internal components of an upper portion of a wall panel and ring beam;

[0049] Figure 5C is an exemplary illustration of a cross-sectional top view (A-A from Figure 4B) of a composite wall panel showing a lap joint, butt joint, and internal wall components;

[0050] Figure 6A is an exemplary illustration of a lap joint connected two wall panels together;

[0051] Figure 6B is an exemplary illustration of internal wall components;

[0052] Figure 6C is an exemplary illustration of a butt joint connected two composite wall panels together; and,

[0053] Figure 7 is an exemplary illustration of a side view of the building system showing an outer face of a wall panel and internal piping.

[0054] DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

[0055] A building system that comprises a floor panel and a composite wall panel is disclosed. The building system may be used for constructing a building or housing unit. The building or housing unit may be suitable to enable construction of housing units for various applications, including low-cost housing. The building system may be designed for the purposes of constructing the building or housing units in a short timeframe and at scale. Examples of such building or housing units may be remote site operations office, staff accommodation, hospitality and leisure units, or education facilities such as classrooms or ablution blocks.

[0056] Particularly, the building system may include a composite wall panel that can provide sufficient structural support for a building unit, while providing a degree of fireproofing, insulation, and weather durability for potentially harsh weather environments. Harsh weather environments may include high or low temperatures, or heavy rains. The building system may include additional components, such as a sub-frame, one or more footings, and a roof.

[0057] The building system may include components that can be manufactured in a manufacturing facility to provide prefabricated components of the building system. The building system may be designed to be assembled on-site during a construction process. The construction process may allow for minimal disruption at a construction site, and minimising risk to the construction workers or contractors.

[0058] The following disclosure may refer to Figures 1 to 7 interchangeably throughout.

[0059] An exemplary illustration of a building or housing unit 100 is shown in Figure 1A. The building unit 100 may include or be constructed by a building system as described herein. The building unit may include features such as a roof, a wall, a floor, plumbing and electrical fittings, a sub-frame, and at least one footing system 150, as will be described. The footing system 150 may raise the building unit above a ground level that the footing system rests on. The building or housing unit 100 may interface with external services to provide regular building functionality, such as running water, sewerage or electrical connections (not depicted).

[0060] A corner portion of the building unit 100, illustrating components of a building system 140, is shown in Figure 1 B. The building system 140 may include a floor panel 104. The floor panel 104 may form a base for the building unit 100 to be constructed on. The building system 140 may include at least one wall panel 102. The floor panel 104 and the wall panel 102 may be joined together to form a core component of the building unit 100.

[0061] The wall panel 102 may be a composite wall panel. The composite wall panel made include multiple materials to improve the insulation, structural and fire-proofing characteristics of the wall panel 102.

[0062] The wall panel 102 may be positioned at an edge of the floor panel 104. The wall panel 102 may extend generally vertically at an edge of the floor panel 104. A plurality of wall panels 102 may be placed around the edge of the floor panel 104. The combination of the plurality of wall panels 102 and the floor panel 104 may form a structural basis of the building system 140. The modularity and practicality of this combination may allow for many different building unit 100 designs to be constructed, whilst including services and additional features to be easily fitted to the building unit 100.

[0063] The floor panel 104 may be made from any one or more of: timber, glue-laminated timber, crosslaminated timber (CLT), or any other suitable flooring material. The floor panel may be configured to permit services to be passed around or through the floor. Such services may include any one or more of: plumbing, sewerage, and electrical fittings. The floor panel 104 provides a support base for the wall panels 102 to be placed on or around. The floor panel 104 may also allow for additional wall panels to be placed on to form interior walls within a building unit. The wall panels 102 placed at an edge of the floor panel 104 may form an exterior wall of the building unit.

[0064] The wall panel 102 is an integral component of the building system. The wall panel 102 may be a composite wall panel that includes a layer or panel made from CLT. The wall panel 102 may further include a weatherproof panel. The weatherproof panel may be located on an external portion of the wall panel. For example, the weatherproof panel may be a fibre cement panel but it could also be any generally water-resistant barrier that is hard-wearing such as a hemp-based composite or Vitrex™. The weatherproof panel may be directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel 102. The weatherproof panel may help to prevent water from seeping into the CLT, helping to increase the longevity of the building system 140.

[0065] The weatherproof panel may be directly fixed to the CLT panel across substantially an entire surface of the weatherproof panel so that substantially no void exists between the weatherproof panel and the CLT panel. Not having a void and / or air gaps is contrary to other designs which may use vapour barriers, battens or other spacers to create a breathable void and promote ventilation of the wooden structure. By eliminating this void with a direct fixing (also termed “faceseal”), the walling system can be packed and transported more densely and efficiently, assembled much more quickly on site and requires less on-site finishing and maintenance. These advantages enable a cost-effective building solution to be applied in the use cases that have been described. Eliminating air gaps between the CLT and the weatherproof panel reduces the risk of any condensation between the CLT and the weatherproof panel, which may degrade the wood. It also protects the wood from fungus, insects, and physical damage.

[0066] T o accomplish direct fixing, the weatherproof panel may be fixed to the CLT panel by an adhesive or sealant, such as an expanding polyurethane adhesive, and optionally reinforced by means of pins or nails driven through the weatherproof panel into the CLT panel. In one example, the pins or nails may be brad nails such as rapid small head brad nails, which can be driven in by a pneumatic nail gun. Directly bonding the weatherproof panel to the CLT may include completely covering the surface of the CLT in an adhesive or sealant before applying the weatherproof panel to the CLT, and then driving the pins or nails through the weatherproof panel and into the CLT panel. The addition of pins or nails also assists in reducing or eliminating the risk of delamination as well as avoiding air pockets within the adhesive.

[0067] The CLT panel may include multiple layers of timber (see 404A in Figure 5A). The timber may include fibres. The layers of timber may be positioned such that the fibres in one layer of timber are placed in different orientations to fibres in other layers. The differing orientations of the fibres in the layers may provide improved structural performance and dimensional stability of the CLT layer and the wall panel 102 in multiple directions.

[0068] An internal surface on the wall panel 102, at the opposite side of the wall panel 102 to the weatherproof panel, may have a polyvinyl chloride (PVC) or vinyl sheeting directly fixed to the CLT to form a sealed waterproof wall. The internal surface may optionally be treated to form a finished surface. Alternatively, the internal surface may have a fibre cement panel directly fixed to the CLT to form a sealed waterproof inner layer. In some examples, the internal surface may have waterproof composite barrier that is hard-wearing, a hemp-based composite, or Vitrex™ material directly fixed to the CLT.

[0069] Forming a building unit 100 may require multiple wall panels 102 placed alongside each other. The wall panels 102 may be joined together by joints 122,124. The joints may be a lap joint 122, which may be a joint to connect two wall panels 102 together that extend side by side to each other. A corner joint may be a butt joint 124, which may be a joint to connect two wall panels 102 together that lie out of plane with each other. The butt joint 124 may join two wall panels 102 together at right angles to each other.

[0070] Variations of the joints, including other types of joining techniques, may be used to join the wall panel 102 to the floor panel 104 or the ring beam 108. The wall panel 102 may be joined to the floor panel 104 be joining the lowermost edge of the wall panel 102 on to the floor panel 104, as shown in Figure 5A. The wall panel 102 may be joined to the ring beam 108 by stacking the ring beam 108 on top of the wall panel 108. The ring beam may be stacked by placing the lowermost edge of the ring beam 108 on top of the uppermost edge of the wall panel 102 and joined together.

[0071] In addition to the wall panel 102 and floor panel 104, the building system 140 may include additional features to be used for constructing a building unit 100. The additional features may be any one or more of: a window 106, a ring beam 108, a skirt 110, a sub-frame 112, and a roof 114.

[0072] The skirt 110 may form an important protection barrier for an underside of the floor panel 104 and for additional services (see Figure 5A) that may be placed under the floor panel 104. The skirt 110 may be in the form of a second weatherproof panel that is fixed to a lowermost, exposed section of the CLT panel to complete the weatherproofing of the external face of the composite wall 102. The skirt may extend below a level of an underside of the floor panel. The skirt 110 may extend along an outer edge of the floor panel so as to create a barrier around the edge of the building unit 100. The skirt 110 may function as a drip edge for water that runs down the wall panel 102 to drop to the ground without wetting CLT components like the floor panel 104 or sub-frame 112. The skirt 110 may be the only component of the wall panel 102 that is installed on site, after the wall panel 102 has been attached to the floor, so as to complete the waterproofing or weatherproofing of the wall panel 102. The skirt 110 may also shield and protect any screws or other attachment points. While various dimensions are possible, in one example, the skirt 110 may extend by more than 100mm below an underside of the floor panel 104, for example by about 200 - 300 mm.

[0073] A gap 126 may form between the wall panel 102 and the skirt 110 at an edge of the floor panel 104. The gap may form when the weatherproof panel of the wall panel 102 and the weatherproof panel of the skirt 110 are two separate pieces. The gap 126 may be filled with a sealant to maintain the weatherproofing capabilities of the external face of the building system 140.

[0074] The wall panel 102 may also include a window aperture 106 with a pre-installed window mounted within the window aperture 106. By providing the window aperture and window at the time of manufacturing the wall panel (at a factory), consistent quality may be achieved and on-side work at the time of installation is minimized.

[0075] The building system 140 may sit on a sub-frame 112. The sub-frame 112 may form a foundational base for the floor panel 104 and for the rest of the building system 140. Looking at Figure 2, the sub-frame 112 may include a plurality of beams 210. The beams 210 may be joined together to form a structural framework 200. The sub-frame 112 may support a floor panel 104 on top of the sub-frame.

[0076] Each of the sub-frame 112 and the beams 210 may be made from any one or more of: glue- laminated timber, CLT, or treated lumber.

[0077] The sub-frame may have at least one footing system 150 attached to the sub-frame, as shown in Figures 1A. The footing system 150 may support the sub-frame above the ground level. The entire building system 140 may be positioned and maintained above the ground by the footing system 150.

[0078] Exemplary footing systems 300,350 are shown in Figures 3A and 3B, respectively. Each footing system may be a micro-pile footing system. The footing system 300,350 may include at least one bracket 304,354 which may support one or more piles 356. The piles 356 may be driven into the ground. The piles may be driven in to the ground at different angles to each other so as to provide lateral stability.

[0079] The footing systems 300,350 may include at least one levelling and connection plate 302,352. The levelling and connection plate may be used to connect the footing system 300,350 to the sub-frame 112. The bracket 354 and levelling and connecting plate 352 may be a single manufactured bracket, as shown in Figure 3B. The bracket 304 and levelling and connecting plate 302 may be manufactured separately, as shown in Figure 3A.

[0080] The building system 140 may comprise a design that is generally rectangular in a plan view, thereby resembling a box. The sub-frame 112 may be generally rectangular, as shown in Figure 2. The floor panel 104 may be generally rectangular. The floor panel 104 may be larger in dimension than the sub-frame 112, such that the floor panel extends beyond the boundary of the sub-frame 112. Therefore, the wall panel 102 may be placed on the floor panel 104 outside of the boundary of the sub-frame 112.

[0081] The wall panels 102 may extend on each of four edges of the floor panel 104. The wall panels 102 may be joined together at right angles at each of the four corners of the generally rectangular floor panel 102. The wall panels 102 of the generally rectangular floor panel 104 may be joined together at the four corners by joints, for example butt joints.

[0082] The building system 140 may also comprise more complex floor panel 102 shapes in a plan view with more the four edges and four corners. In the case of more complex designs, a combination of butt joints 124 and lap joints 122 may be used to join wall panels 102 together.

[0083] The micro-pile footing system 300,350 may include one bracket 304,354 towards each corner of the sub-frame 112. At least one bracket 304,354 may be placed between two corners of the subframe 112. The at least one bracket placed between the two corners may support splayed piles. The splayed piles may be driven into the ground to provide lateral stability.

[0084] Figure 4A and 4B illustrate internal features present in the wall panel 102. The wall panel 102 may include multiple layers of different materials, forming a composite wall panel 102. The wall panel 102 may be arranged to extend generally vertically at an edge of the floor panel 104.

[0085] Figure 4A is a cross-sectional side view, highlighting features of the wall panel 102, the floor 104, the sub-frame 112, the ring beam 108, and the roof 114. The wall panel 102 may be made from CLT 404. The wall panel 102 may include a weatherproof panel 402. The wall panel 102 may be a combination of the CLT 404 and the weatherproof panel 402. The weatherproof panel 402 may be directly fixed to the CLT 404. An additional weatherproof panel may form a skirt 110 around the edge of the floor panel 104. A gap 126 may form between the weatherproof panel 402 of the wall panel 102 and the weatherproof panel of the skirt 110. The gap 126 may be filled with a sealant. The sealant may prevent water from reaching the CLT layers 404 of the wall panel. The sealant may also prevent water from reaching the floor panel 104.

[0086] The ring beam 108 may comprise sections that are joined together. The ring beam 108 may extend atop the wall panels 102. The ring beam 108 may form a structural member between the roof 114 and the wall panels 102, provide structural support to the building system 140. The ring beam 108 may support the roof 114, which may rest on top of the ring beam or be fixed to the ring beam 108. The ring beam 108 may comprise four beam sections arranged to follow the edges of the rectangular floor panel.

[0087] The ring beam 108 may be made from CLT. External faces of the ring beam 108 may have a weatherproof panel directly fixed to them. The external weatherproof panel may provide a weatherproof layer to the ring beam 108 to prevent water from seeping into the ring beam 108.

[0088] Figure 4B further shows internal features of the wall panel 102, including; a wall panel to floor mounting system 480, a ring beam mounting system 450, and a cross-sectional slice A-A 460. These features are shown in further detail in Figures 5A, 5B, and 5C, respectively.

[0089] Figure 5A shows the wall panel to floor mounting system 480 in further detail. The sub-frame 112 may be set back from at least one edge 506 of the floor panel 104. A space or channel 502 may form underneath the floor panel 104 between the sub-frame 112 and the lowermost portion weatherproof panel of the skirt 110. The channel 502 may be partially shielded from view by the skirt 110. The channel 502 may be protected or partially shielded from weather. The channel 502 may be protected from water running down the wall panel 102 due to the skirt 110 extending below the underside of the floor panel 104. The channel 502 may accommodate conduits or services 504 for the building system. The channel 502 may accommodate any one or more of: water pipes, electrical cabling, trunking, conduits, or lighting.

[0090] The wall panel 102 may be connected to the floor panel 104 by at least one screw 503. The screw 503 may be positioned at an angle non-perpendicular to a normal direction of the wall panel 102. The angle of the screw 503 may allow for the screw to 503 to penetrate both the wall panel 102 and the floor panel 104. The floor panel 104 may be connected to the sub-frame 112 by at least one screw 505. A sealant or adhesive may be used to join the various panels 102,104 and subframe 112 together.

[0091] Figure 5B shows a ring beam mounting system 450, which shows the joining of the wall panel 102 with the ring beam 108. The wall panel 102 and ring beam 108 may be joined by at least one set of screws 507. The screws 507 may be placed at an angle non-perpendicular to the surface of the wall panel 102. The non-perpendicular angle allows the screws to be inserted through both the wall panel 102 and the ring beam 108 simultaneously. The screws 507 may be inserted in the wall panel 102 from an interior facing surface. The interior facing surface may be on the side of the CLT panel 404.

[0092] An entry point of the screws 503,505,507 on the surface of the respective panel may be sealed and covered. This may improve the aesthetics of the surface. Sealing the entry point of the surfaces may ensure weatherproofing of the panel is maintained.

[0093] Figure 5C shows a cross-sectional top view of the wall panel 102. The wall panel 102 may include: a lap joint 550, a butt joint 570, and internal fitting components 560.

[0094] The lap joint 122 and butt joint 124 are shown in Figures 6A and 6C, respectively. The joints allow for two wall panels to be joined together. The lap joint 122 may be used to join wall panels together when the panels are side by side with each other. The butt joint 124 allows for two wall panels to be joined together when the two panels are at right angles to each other. The butt joint 124 can allow for a limited degree of misalignment.

[0095] In Figure 6A, each of the composite two wall panels 102 may comprise inner CLT panels 603,605 each including an outer weatherproof panel 402 that may be directly fixed to the CLT panels. The CLT panels 603,605 may have an internal face 601 that is positioned towards an interior of a building unit 100. The weatherproof panel 402 may be directly fixed 608 to the CLT panels 603,605 at the intersection between the weatherproof panel and CLT panels. The direct bonding may restrict the ability for liquid to pass through the weatherproof panel 402 to the CLT panel 603,605.

[0096] Two CLT panels 603,605 may each have a corresponding lap joint 122 edge. The CLT panels 603,605 may be configured such that, when pressed together, a gap 602 may form between the panels 603,605 at the external-facing side of the wall panels by the weatherproof panel 402. A backing cord 606 may be placed within the gap 602. The backing cord 606 may be covered by a sealant 607 to form a flush and waterproof finish between faces of the weatherproof panel 402. The sealant may ensure that the wall panels 102 have sufficient waterproofing to prevent liquid from entering into the lap joint 122.

[0097] The wall panels may be configured such that, when pressed together, the CLT panels 603,605 are in contact with each other at the internal-facing side, or internal face 601 , of the wall panels.

[0098] The CLT panels 603,605 may be configured such that a notch 604 forms at the internal face 601 when the panels are joined. The notch 604 may be filled with a sealant to provide a seal between the CLT panels on the interior-facing side of the wall panels 102.

[0099] A feature of the lap joint is that a gap 602 exists between the panels 603,605 only on the externalfacing side, while simultaneously, no gap exists between the panels 603,605 at the internal face 601 of the panels. This feature allows for the backing cord 606 to be placed in the gap and for the gap 602 to be filled with a sealant 607, forming a weatherproof seal from both sides of the wall panels.

[0100] A screw 610 may be inserted through the lap joint 122 to join the two CLT panels 603,605 together. The screw 610 may be inserted into holes in the panels 603,605. The holes may be precored and pre-drilled. The pre-drilled holes may be at a non-perpendicular angle with the internal face 601 such that the screw penetrates into both CLT panels 603,605. The entry point of the screw in the CLT panel 605 may be covered with a sealant to form a flush surface finish.

[0101] The pre-cored and pre-drilled holes may also be used to join the wall panels 102 to the floor panels 104. The pre-cored and pre-drilled holes may also be used to join the wall panels 102 to the ring beam 108. The pre-cored and pre-drilled holes may also be used to join the floor panels 104 to the sub-frame 112.

[0102] The lap joint 122 may be any one of the group of: a half lap joint, a mitred half lap joint, a cross lap joint, a dovetail crossed lap joint, a half lap splice joint, a bevel lap splice joint, or a tabled splice lap joint.

[0103] Internal components 560 of the wall panel are shown in Figure 6B. The wall panel 102 may include one or more plug sockets 622. Space for the plug socket 622 may be cut out of the CLT panel. The wall panel 102 may include pre-drilled conduits 620 within the wall panel. The pre-drilled conduits 620 may include electrical conduits and / or plumbing pipes. The pre-drilled conduits 620 may be on the exterior-facing side of the wall panel and cut into the CLT. The pre-drilled conduits 620 may be covered by the weatherproof panel 402. Figure 6C shows two CLT panels 653,655 joined together by a butt joint. The wall panels are configured such that no gap exists between 646 the CLT panels. A gap may exist between adjacent weatherproof panels 402. The gap may be filled with sealant 640 to ensure weatherproofing of the butt joint, as to not allow any liquid to pass through to the CLT panels.

[0104] A hole may be pre-cored and pre-drilled into the panels 653,655 to insert a screw 644 into. The screw 644 may be inserted into a panel 653 through the weatherproof panel 402. The screw 644 may enter the corresponding panel 655 at the intersection 646 between the two panels. After the screw 644 is inserted, the hole may be filled and sealed 642.

[0105] Figure 7 shows an illustration of an external view of the building system 140 and weatherproof panel 402. The screws 644 for the butt joint are shown in figure 7 near a corner of the building system. An example conduit 704 is shown running along the sub-frame 112 and through the floor panel. The conduit 704 is partially obstructed from view by the skirt 110.

[0106] The building system 140 as disclosed may be incorporated into a kit. The kit may include individually manufactured components to construct the building system 140. The kit may include a prefabricated floor panel 104 and at least one wall panel 102. The at least one wall panel 102 may be a prefabricated wall panel. The at least one wall panel 102 may be composite wall panel. The composite wall panel may be made from CLT. The at least one wall panel 102 may have a weatherproof panel directly fixed to the CLT panel.

[0107] The kit may include a second weatherproof panel. The second weatherproof panel may be used to form a skirt 110. The skirt may be designed to extend free of the wall panel and the floor panel to project beneath the floor. The kit may be flat-packed and shipped to its destination being a building site where it can be assembled into a building unit as described.

[0108] A method of building a structure is also disclosed. The method may include providing a prefabricated floor. The prefabricated floor may be a floor panel 104. Providing the prefabricated floor may include manufacturing the prefabricated floor in a manufacturing facility.

[0109] The method may further include providing at least one prefabricated wall panel. The prefabricated wall panel may be a composite wall panel 102. Providing the prefabricated wall panel may include manufacturing the prefabricated composite wall panel in a manufacturing facility. The composite wall panel may comprise CLT and a weatherproof panel directly fixed to the CLT. Providing the prefabricated wall panel may include directly bonding the weatherproof panel to the CLT. The prefabricated wall panel may be mounted generally vertically at the edge of the prefabricated floor. Mounting the prefabricated wall panel may include: raising the prefabricated wall panel above the prefabricated floor, aligning the prefabricated wall panel at an edge of the prefabricated floor, aligning the holes for screws to be inserted into the prefabricated wall panel and prefabricated floor, applying adhesive or sealant between the prefabricated floor and prefabricated wall panel, tightening the screws, and allowing for the sealant / adhesive to set.

[0110] The weatherproof external face of the prefabricated wall panel may be outward facing. Weatherproofing material may optionally be applied to the prefabricated wall panel at an inward facing side of the prefabricated wall panel. Once the prefabricated wall panel is mounted to the prefabricated floor, a second weatherproof panel may be attached to a lowermost, exposed portion of the prefabricated wall panel. The second weatherproof panel of the wall may form a skirt which completes weatherproofing of the wall. The skirt may extend below a level of the underside of the floor panel.

[0111] The second weatherproof panel may be directly fixed to the CLT panel of the prefabricated wall panel and to the prefabricated floor.

[0112] The foregoing description has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the technology to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure.

[0113] The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the present disclosure be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the present disclosure is intended to be illustrative, but not limiting, of the scope of any accompanying claims.

[0114] Finally, throughout the specification and any accompanying claims, unless the context requires otherwise, the word ‘comprise’ or variations such as ‘comprises’ or ‘comprising’ will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. CLAIMS:

1. A building system comprising: a floor panel; and at least one composite wall panel which extends generally vertically at an edge of the floor panel; wherein the composite wall panel includes a cross-laminated timber (CLT) panel with a weatherproof panel directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel.

2. The building system of claim 1 wherein the weatherproof panel is directly fixed to the CLT panel across substantially an entire surface of the weatherproof panel so that substantially no void exists between the weatherproof panel and the CLT panel.

3. The building system of claim 1 or claim 2 wherein the weatherproof panel is directly fixed to the CLT panel by an adhesive or sealant.

4. The building system of any one of claims 1 to 3 wherein pins or nails are driven through the weatherproof panel into the CLT panel to reinforce the direct fixing of the weatherproof panel to the CLT panel.

5. The building system of any one of claims 1 to 4 wherein the weatherproof panel is a fibre cement panel.

6. The building system of any one of claims 1 to 5 wherein a second weatherproof panel is provided and is fixed to a lowermost, exposed section of the CLT panel to form a skirt which completes weatherproofing of the external face of the composite wall panel and which extends below a level of an underside of the floor panel.

7. The building system of claim 5 wherein the skirt forms a drip edge for water running down the external face of the composite wall panel.

8. The building system of claim 6 or claim 7 including a sub-frame to support the floor panel, with the sub-frame being set back from at least one edge of the floor panel.

9. The building system as claimed in claim 8 wherein the sub-frame is made from glue- laminated timber beams joined together in a structural framework.

10. The building system as claimed in claim 8 or claim 9 wherein a channel is formed between the skirt and the sub-frame, the channel being at least partially shielded from view by the skirt, and wherein the channel accommodates conduits or other services.

11. The building system as claimed in claim 10 wherein the channel accommodates one or more of: water pipes, electrical cabling, trunking, conduits, and lighting.

12. The building system as claimed in any one of claims 1 to 11 wherein the floor panel is generally rectangular in plan view, and wherein composite wall panels extend on each of four edges of the floor panels, with the composite wall panels joined together at right angles at four corners of the floor panels.

13. The building system as claimed in claim 12 wherein the composite wall panels are joined at the four corners by butt joints.

14. The building system as claimed in claim 12 or claim 13 wherein a ring beam comprising four beam sections joined together extends atop the composite wall panels and supports a roof structure.

15. The building system as claimed in claim 14 wherein the ring beam is made from CLT and external faces of the ring beam have weatherproof panels directly fixed to them.

16. The building system as claimed in any one of claims 1 to 15 wherein two or more wall panels extend side by side at the edge of the floor panel, the wall panels being joined together by butt joints or lap joints.

17. The building system as claimed in claim 16 wherein the joints include a gap at externalfacing sides of the composite wall panels, and wherein a backing cord is provided within the gap and covered by a sealant to form a flush outer finish.

18. The building system as claimed in claim 8 wherein the sub-frame is supported by a micropile footing system, the micro-pile footing system including at least one bracket which supports multiple piles to be driven into the ground at different angles to each other, the bracket including a levelling and connection plate to the sub-frame.

19. The building system as claimed in claim 18 wherein the sub-frame is generally rectangular in plan view and the micro-pile footing system includes one bracket towards each corner of the sub-frame, as well as at least one bracket between two corners of the sub-frame that supports splayed piles to be driven into the ground for additional lateral stability.

20. The building system as claimed in any one of claims 1 to 19 including a window aperture in the composite wall panel and a window mounted within the composite wall panel.

21. The building system as claimed in any one of the preceding claims including pre-drilled conduits and plug sockets within the composite wall panel.

22. The building system as claimed in claim 21 including electrical conduits and plumbing pipes within the pre-drilled conduits.

23. The building system as claimed in any one of claims 1 to 22 wherein an internal face of the composite wall panel includes polyvinyl chloride (PVC) or vinyl sheeting directly fixed to the CLT panel to form a sealed waterproof wall.

24. A kit for a building system, the kit including a prefabricated floor panel and at least one prefabricated composite wall panel that includes a cross-laminated timber (CLT) panel with a weatherproof panel directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel.

25. The kit as claimed in claim 24 including a second weatherproof panel sized to be fixed to a lowermost, exposed section of the CLT panel to form a skirt to complete weatherproofing of the external face of the composite wall panel and which, when fixed, extends below a level of an underside of the floor panel.

26. A composite wall panel for a building system, comprising a cross-laminated timber (CLT) panel with a weatherproof panel directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel.

27. A method of building a structure comprising: providing a prefabricated floor; providing a prefabricated composite wall panel which includes a cross-laminated timber (CLT) panel with a weatherproof panel directly fixed to the CLT panel to form a weatherproof external face of the composite wall panel;mounting the composite wall panel generally vertically at the edge of the floor with the weatherproof external face being outward facing.

28. The method as claimed in claim 27 including, once the composite wall panel is mounted to the floor, fixing a second weatherproof panel to a lowermost, exposed section of the CLT panel to form a skirt which completes weatherproofing of the external face of the composite wall panel and which extends below a level of an underside of the floor panel.

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