"WALL SYSTEM"

BACKGROUND OF THE INVENTION Field of Invention This invention relates to pre-formed or pre-cast building panels and methods of manufacturing these panels. The invention also relates to building panels that are pre-cast using an improved casting bed.

This invention also relates to an improved apparatus for fastening pre-formed building panels together, and a method of fastening building panels in place using the improved apparatus. This invention also relates to an improved method of casting other building elements into a pre-formed building panel.

Description of the Prior Aft

Pre-casting structural elements such as wall or floor panels is a method used to form prefabricated building elements that is well-known in the construction art. Prefabricated wall panels are typically cast either at a location other than the building site or sites where they are to be used, with the sections then delivered to sites as required, or they are cast on-site. When formed (and if necessary transported to the required location), they are assembled to form part of an overall structure, such as a house. The pre-forming method of construction can help overcome logistical disadvantages in building construction. Building timescales can be reduced, workflow on site can be improved, and reliance on on-site construction is removed or reduced.

The forming techniques used to create these panels have become increasingly sophisticated since their introduction. Panels can be formed that include integral wire mesh or metal reinforcing bars to strengthen the structure. Panels can be formed that include hooks or eyes to facilitate transport or connection of the panel to the building structure. Lightweight inserts such as foam or polystyrene can be used to help shape and form these panels.

US 5,313,753 discloses a prefabricated panel and a method of forming the panel. An outer frame 54 is created from pre-formed elements, and is used to define the outer boundary of the panel. Preformed and pre-sized elements, appropriate for use with this specific size and shape of outer frame 54, are placed within the perimeter of this frame — e.g. service channels 20, polystyrene blocks 16, reinforcing rods 64. These elements are fitted within the frame in a predetermined manner so that there are no gaps between the elements. This creates a base

within the outer frame. Concrete is then added, filling the frame and covering this 'base'. Once the concrete has set, the completed panel is ready for use and can be transported to a building site. The studs created using the method disclosed in US 5,313,753 are formed as part of the concrete pour, and run essentially the full depth of the panel. The construction disclosed leaves no airgaps or air channels, and elements such as cable runs 48 have to be factored in during the pre-forming process. This removes a degree of flexibility from the construction. The manner in which the mix of elements is added and arranged in the outer mould framework can also tend to work against flexibility and modularity. The polystyrene blocks 16 are a standard depth, and run from the mould surface to the required height. If a different thickness of concrete panel is required, a different set of blocks of a different size must be used.

US 4,751,803 discloses a panel forming method and a panel thus formed that allows a greater degree of flexibility. Pre-formed beams or framing members 16 form an outer framework, with support members 18 located within the framework at the base and supporting concrete studs 20 to form a 'skeleton'. The outer framework and inner stud pattern can be varied in size and overall shape. The studs 20 include upwardly facing fasteners 24. Once the framework is laid in place, a rigid insulation sheet 26 is laid over the top of the framework and held in position by impaling it on these fasteners. A wire mesh is then laid over the top of the insulation sheet, with the fasteners protruding upwards through the mesh. Steel rebar is also inserted. The finished panel is created by pouring concrete over and through the mesh and the sheet. The studs and the framework are held in place by the fasteners, which become embedded in the concrete panel after the poured concrete has set.

In the panel created using the method of US 4,751,803, there is some contact between the fresh poured concrete and the edge sections of the frame. However, the main structural contact between the pre-formed studs and the fresh concrete pour that forms the flat concrete panel is via the fasteners. As described above, the studs and the newly poured concrete are separated by the plastic sheet or panel, and are only connected via the fasteners. While this configuration has the advantage of constructional flexibility, the final product may not be suitable for some applications, for example where structural strength is required between the panel and the studs. It should also be noted that the method described in US 4,751,803 is what is known in the construction art as a 'double pour' method. That is, the studs 20 are formed separately from a 'first pour' of concrete, prior to being laid out in the grid pattern shown in figure 1 of US 4,751,803. The fresh concrete pour over the top of the grid is the 'second pour' that forms the

flat concrete panel. It should also be noted that the concrete studs 20 of US 4,751,803 (those formed in the first pout) need to be formed with all the necessary fasteners already in place, and with apertures for wiring or other items formed into each of the studs 20 during this first pour, or subsequently machined in. As two pours are required, time and complexity is added to the panel forming method. Also, as the studs 20 are formed from concrete, they are heavy. If not formed on site, the studs need to be stored and then transported to the forming site. Storing and transporting heavy concrete studs adds to the complexity of the building logistics, and usually requires additional storage space.

Furthermore, it should be noted that the studs 20 are formed with strips 22 located on what will in use be the inner facing side of the wall panel. This arrangement can limit the options that are available for attachment of inner dtywall panels (drywall is also commonly known as gypsum board, plasterboard, and GIB™ board, depending on the country). The material (e.g. wood) used to form the strips 22, and their thickness, will at least partly dictate the panel attachment mechanism. Also, it should be noted that the final construction of the panel of US 4,751,803 includes support members 18 bounding the panel. This arrangement adds complexity and weight to the final construction.

A further difficulty that can arise when casting concrete panels is mitring the lip correctly. When casting, one (or more) walls of the mould can be angled, usually at 45 degrees, so that the edge face of the finalised panel is angled. This angled edge face can be butted up against a similarly formed angled edge face to create a mitred 90 degree corner. If the mould is formed with what will be the outer face of the panel towards the forming surface or floor, it can be difficult to correctly form these corners, as one wall of the mould will be required to be angled inwards. As concrete is poured, it can tend to cavitate (cause cavities) against the inner face of the wall of the mould. This means that this face of the panel, once removed from the mould, will not be smooth or perfectly formed.

Another difficulty that can arise with the forming methods known in the art is rotational Efting of the panels. That is, lifting the panels from the flat, horizontal alignment into a vertical alignment. The standard panel forming method is, for the sake of simplicity, to form the panel horizontally, usually by pouring wet concrete into a flat and wide container. In use, wall panels are aligned vertically, and the finalised panel will need to be rotated and lifted out of the casting bed into a vertical orientation. Because the forces exerted on the panels when they are lifted are generally greater than those they will experience in daily use, It is usually necessary to overdesign

them. That is, a panel must be designed to withstand the stresses it will experience as it is rotated and lifted from a horizontal position to a vertical position. These stresses are greater than those it will experience once in position. This problem can be exacerbated by prior art bed casting apparatus and methods, where additional suction forces must be overcome as the wall panel is lifted from a horizontal position in/on the casting bed, into a vertical, 'use' position.

An additional difficulty that can be experienced when building structures using prefabricated elements such as building panels is the difficulty of correctly aligning these elements and fastening them together. It is standard practice in the building industry to cast a number of apertures into the top edge of a building panel - for example, the top edge of a ground floor external wall panel. These could also be machined into the top edge post-casting. A number of complimentary fastening elements are set into the lower edge of a first floor panel, extending downwards. The first floor panel is hoisted into position above the ground floor panel, and manoeuvred into position so that the downwardly extending fastening elements locate into the apertures. Usually, the apertures are filled with chemset or a similar fastening chemical. The chemset bonds the fasteners into the lower panel, binding the top and bottom panels together. It can be seen that the tolerance range in the location of the apertures, and the location of the fasteners, is critical. If the location of the apertures or the fasteners is not correct, the upper and lower panels will not correctly align. Rectifying this can be expensive and time-consuming.

A third difficulty with using pre-cast construction elements is that of forming windows and doors into wall panels during the panel forming process. Windows usually have an upper head and a lower sill, which extend horizontally backwards (i.e. into the room) from a vertical frame, which passes through the concrete panel. The frame holds the glass pane of the window in place. Apart from this, windows are generally not standard structures. Therefore, the builder must either maintain a large library of various window sizes, or custom make every window mould. The most commonly used prior art forming method is to build a wooden mould, pour the concrete, remove the mould and then insert the window frame and glass.

It can be seen that there exists a need in the construction industry for a simplified method of creating pre-cast sections with integral studs, where the studs are not formed in a separate pour. Also, there exists a need for a panel forming method and a panel which has studs that can be easily formed, stored and transported, and where the studs allow for the use of a greater variety or increased range of e.g. drywall fasteners, which can be easily added after to panel is formed. Also, where the studs can be easily machined post-casting, for example to add holes for cable conduits, etc. Also, where the panel can be formed face-up, with mitred corners.

There also exists a need in the construction industry for a simplified method and construction for fastening a panel in place, for example to fasten the panel to another panel, decreasing the reliance on correct manufacturing tolerances in two separate elements.

There is also a need in the construction industry for a method of casting elements such as windows and doors in place in wall panels, in thek final form. This method would decrease or remove the need for additional post-casting and post-transporting work.

SUMMARY OF THE INVENTION

In a first aspect, the invention consists in a building panel, comprising: a concrete portion, having an inner surface and an outer face, a plurality of insert blocks embedded in said concrete portion to form said inner surface along with part of said concrete portion, said inner surface being substantially planar, a planar plastic panel covering said planar inner surface, a plurality of spacing members located against die outer face of said plastic panel, each of said spacing members including at least one fastening member that protrudes through said plastic panel and into said concrete portion, such that said fastening members are embedded in said concrete portion.

Preferably said fastening members are embedded in said concrete section, between said insert blocks. Preferably said plastic panel is a polystyrene panel having a minimum thickness of 20mm.

Preferably said insert blocks are positioned in parallel block rows along said plastic panel and are sized to reach from one edge of said plastic panel to the opposite edge.

Preferably said spacing members are elongate members positioned parallel to one another, spaced apart along said panel to form parallel spacer rows, said elongate members having an outer surface parallel to the plane of said plastic sheet and spaced from said outer face of said plastic panel.

Preferably said parallel block rows is from 400mm to 600mm on centre, and the distance between said parallel spacer rows is from 400mm to 600mm on centre.

Preferably said outer surface is spaced a distance of between 25mm and 45mm from said outer face of said plastic panel.

Preferably said elongate members are U-channel beams, one side wall of said U-channel abutting said sheet, said side walls having a height of 35mm, said base of said U-channel having a width of 65mm.

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Preferably said fasteners protruding beyond said plastic sheet is at least half the total length of said fastener.

Preferably said fastening members are each between 60mm and 80mm long, and the number of said fastening members per elongate member is at least 5. Preferably said insert blocks are formed from foamed polystyrene.

Preferably said insert blocks are formed as hollow constructs.

Preferably said hollow constructs are filled with an insulation material such as mineral wool, natural wool or polyester wool.

Preferably said insert blocks has a height of at least 40mm. Preferably said insert blocks have angled side walls, the face of each of said blocks that contributes to said inner surface being broader than the corresponding opposite face, said base having a width of between 400mm and 550mm , said top having a width of between 350 and 500mm.

Preferably said spacing elements are positioned such that said parallel block rows are interspersed between said parallel spacers.

Preferably said building panel also includes a plurality of rebar elements embedded in said concrete section.

Preferably said building panel is aligned at an angle to said inner face.

Preferably said angle is chosen, and said end is shaped, to allow said end to interlock with a mutually complimentary formed end of a second one of said building panels placed adjacent said first panel.

Preferably said angle is 45 degrees.

Preferably said building panel includes at least one corner connector partially embedded in said concrete portion, with part of said corner connector extending from said concrete portion to enable connection of said building panel to an adjacent building panel of similar construction.

Preferably said building panel is shaped to allow said edge to interlock with a mutually complimentary formed edge of a second one of said building panels placed adjacent said first panel, said interlocking forming a cavity between said interlocking panels suitable for insertion of one edge of a wall stud. In a second aspect, the invention consists in a method of forming a concrete building panel comprising the steps of: forming an enclosed-perimeter outer framework, positioning at least one spacing member within said outer framework, each of said spacing member or members including at least one fastening member extending upwards,

placing a planar plastic panel within said frame over the top of said spacing members, with the upper portion of said fastening members protruding through the upper surface of said plastic panel, said plastic panel sized to fit within said outer framework, positioning a plurality of insert blocks on said plastic panel, pouring concrete into said frame to cover said plastic panel, said fastening members, and said insert blocks.

Preferably said method includes the step of removing said outer framework once said concrete has solidified.

Preferably said method includes the step of inserting a plurality of reinforcing elements within said outer framework after said insert blocks are positioned on said plastic panel, and before said concrete is poured.

Preferably said method also includes the step of positioning a corner connector element in said outer framework before said concrete is poured, in such a manner that at least part of said corner connector element protruding from said building panel. Preferably said blocks are sized and positioned such that the space between at least one end of each of said blocks and the wall of said frame is between 50mm and 400mm.

In a third aspect, the invention consists in a casting bed for the creation of at least one building panel, comprising: a plurality of beam members, arranged in substantially parallel rows, a plurality of mould sections, connected to one another to form at least one enclosed- perimeter mould, a clamping mechanism adapted to clamp said enclosed perimeter mould onto the top of said beam members, said beam members adapted to receive clamping mechanism.

Preferably said beam members are I-section beams, the upper part of said beam members adapted to receive said clamping mechanism.

Preferably said beam members have a length between 50m to 150m, with the outer ones of said beam members spaced apart between 2m and 3m.

Preferably said bed includes at least four of said beam members arranged in parallel, and arranged at equally spaced intervals. Preferably said bed includes at least four of said beam members arranged in parallel, and the inner ones of said beam members are spaced at intervals of between 200mm and 2000mm from the outer ones of said beam members.

Preferably said mould sections are elongate framework members that can be bolted together to form said mould.

Preferably said mould sections are shaped so that when cast, said building panel will have shaped edges.

Preferably said mould section are adapted such that at least one of said mould sections can be angled from the vertical when attached to the others of said mould sections, so that when cast, at least one edge of said building panel will be at an angle.

In a fourth aspect the invention consists in a building panel, comprising: a concrete portion, having an inner face, an outer face, and an enclosing boundary portion around the perimeter of said inner face, a rigid planar plastic sheet having an outer face, and an opposed inner face fitting against and sized with said concrete portion inner face, a plurality of spacing studs located against said outer face of said plastic panel, each of said spacing studs including at least one fastening member that protrudes through said plastic panel and into said concrete portion, such that said fastening members are embedded in said concrete portion. Preferably said boundary portion has four sides, the first, second and third of said sides having a substantially flat inner face, said first and second sides parallel, said building panel also including parallel spacer blocks located against said flat inner faces of said first and second sides, said spacer blocks the same width as said faces, and a timber top plate, one face of said timber top plate located against the inner face of the fourth side of said boundary portion, said timber top plate sized to cover said fourth side.

Preferably said building panel includes steel mesh and rebar elements embedded within said concrete portion.

Preferably said concrete has a compressive strength of approximately 40MPa.

Preferably said parallel spacer blocks run the full length of said building panel, and said Preferably said building panel includes a service channel located against, and running the length of, said one face of said timber top plate.

Preferably said timber top plate has a profile width of between 130 and 150mm, and a profile depth of between 35mm and 55 mm, and said parallel spacer blocks each have a profile width of between 130mm and 170mm and a profile depth of between 23mm and 70mm, said spacer blocks being the same length as the sides of said building panel.

Preferably said building panel includes a plurality of bolts, protruding from said inner faces of said boundary portion and embedded in said spacer blocks.

Preferably said bolts are 130mm Ml 2 bolts embedded in said spacer blocks to a depth 5mm less than the depth of said spacer blocks.

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Preferably said building panel also includes a plurality of screws, passing through said timber top plate and said service channel, and into said concrete.

Preferably said building panel is between 180 and 220mm, and said plastic sheet has a thickness of between 25mm and 60mm, and the length of said fasteners is 75mm. Preferably said spacer blocks, the inner face of said timber top plate and the inner portion of said spacing studs all lie in substantially the same plane.

Preferably said service channel is formed from a u-channel section attached to said timber top plate, with the open face of said channel facing said top plate.

Preferably said service channel is a USG ceiling batten with a depth of 23mm and a base width of 37mm.

Preferably said building panel also includes a perpendicular spacer block located against and fully covering the third side of said boundary portion, perpendicular to said parallel spacer blocks and parallel to said timber top plate, said perpendicular spacer block the same length as the closest, parallel edge said plastic sheet, and the same width as the adjacent flat inner face. Preferably said perpendicular spacer block has a profile width of between 60mm and

110mm and a profile depth of between 30mm and 50mm.

Preferably said building panel are perpendicular to said panel outer face, except for the edge face which is adjacent one of said parallel spacing blocks, which is angled inwards towards said spacing studs and said plastic panel. Preferably said inwards angle is 45 degrees.

Preferably said spacing studs are steel U-channels, aligned so that one side of said channel abuts said plastic panel, the outer ones of said spacing studs arranged to form a closed perimeter inner framework around the edges of said outer face of said planar plastic panel, the bases of the channels that form said closed perimeter aligned to face outwards from said inner framework towards said enclosing boundary portion.

Preferably said spacing studs have a width across the base of said u-channel of between 50mm and 100mm.

Preferably said spacing studs have a width across the base of said u-channel of 64mm, said building panel having an overall width of 200mm, such that the thickness of concrete from said concrete portion inner face to said panel inner face is 86mm.

Preferably said spacing studs have a width across the base of said u-channel of 51mm, and said plastic sheet has a thickness of 30mm, said building panel having an overall width of 200mm, such that the thickness of concrete from said concrete portion inner face to said panel inner face is 119mm.

Preferably said spacing members have a width across the base of said u-channel of 90mm, and said plastic sheet has a thickness of 50mm, said building panel having an overall width of 200mm, such that the thickness of concrete from said concrete portion inner face to said panel inner face is 60mm. Preferably said U-beams are filled with polystyrene.

Preferably said spacing members are closed sections, having a depth of 23mm, and said plastic sheet has a thickness of 25mm, said building panel having an overall width of 200mm, such that the thickness of concrete from said concrete portion inner face to said panel inner face is 151mm. Preferably said closed sections are formed from USG ceiling battens, the top of the channel of said battens including a plate which closes said channel.

Preferably said building panel are perpendicular to said panel outer face, except for that edge face which is adjacent one of said parallel spacing blocks, which is angled inwards towards said spacing studs and said plastic panel. Preferably said inwards angle is 45 degrees.

Preferably said spacing members have a width across the base of said u-channel of 90mm, and said plastic sheet has a thickness of 50mm, said building panel having an overall width of 200mm, such that the thickness of concrete from said concrete portion inner face to said panel inner face is 60mm, all the edge faces of said building panel substantially perpendicular to said panel inner face.

Preferably said U-beams are filled with polystyrene.

Preferably said building panel includes at least one intertenancy spacer on said building panel outer face, held in place by fasteners protruding downwards into said concrete.

Preferably said panel includes at least two and preferably three intertenancy spacers, arranged in parallel and running substantially from the top to the bottom of the building panel.

Preferably said spacing studs lies in a plane between 8mm and 12mm further towards said outer face of said building panel than said inner faces of said spacer blocks and said inner face of said timber top plate.

Preferably said building panel also includes at least one embedded wall panel fastener, said panel fastener comprising a hollow fastening tube and a main body, said main body embedded in said concrete panel, said fastening tube passing through one side of said boundary portion.

Preferably said at least one fastening tube is sized and aligned to pass through that side of said boundary portion adjacent to said perpendicular spacer block.

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Preferably said main body is an elongate member bent to form a panel portion and a connection portion, said panel portion embedded between said inner face and said outer face of said concrete portion, said connection portion passing between and connecting said panel portion and said fastening tube. Preferably said wall panel also includes a portal, passing through said concrete portion and said planar plastic sheet, said portal comprising: an open-ended box frame, the inner edges of said box frame planar with inner side, a portal frame element, the inner part of said frame element adjacent the outer edges of said box frame, the outer part of said frame element embedded in said concrete portion. Preferably said box frame and said portal frame element is surrounded by polystyrene blocks.

Preferably said polystyrene blocks and said portal frame element are surrounded by a PVC barrier sheet arranged such that said concrete and said frame are not in direct contact.

In a fifth aspect, the invention consists in a method of forming a concrete building panel comprising the steps of:

1) forming an enclosed-perimeter rectangular outer framework,

2) positioning a plurality of spacing studs within said outer framework and spaced from said outer framework, each of said spacing members including a plurality of fastening members extending upwards, 3) placing a planar plastic panel within said frame over the top of said inner framework, the upper portion of said fastening members protruding through the upper surface of said plastic panel, said planar plastic panel si7ed and shaped to substantially match the size and shape of said inner framework,

4) pouring concrete into said frame to cover said plastic panel and said fastening members, and fill said outer framework to the required depth,

5) removing said outer framework once said concrete has cured.

Preferably said spacing studs are arranged to form an inner framework with a rectangular and closed perimeter.

Preferably said method also includes the steps of placing plastic spacer blocks and a timber top plate in the space between said inner framework and said outer framework before said concrete is poured, said timber top plate having the same length as one side of said inner framework, the width of said top plate the same as the distance between adjacent parallel walls of said inner framework and said outer framework, said plastic spacer blocks arranged to fill at least the gap between the ends of said timber top plate and said outer framework and the space

between said inner framework and the outer framework on the sides perpendicular to said top plate.

Preferably said method includes the step of attaching a channel section to said top plate to form a service channel, said channel section running the length of said timber top plate. Preferably said method also includes the step of placing at least one spacing stud inside said inner closed perimeter as part of said inner framework.

Preferably said method includes the step of embedding bolts in said spacer blocks, aligned upwards.

Preferably said bolts are embedded in said spacer blocks in such a manner that the lower ends of said bolts are a minimum distance of 5mm from the lower face of said spacer blocks.

Preferably said spacer blocks and the lower face of said top plate are emplaced so that they He in the same plane as the lower edge of said inner framework.

Preferably said method includes the step of placing shims underneath said spacing studs before said concrete is poured in order to space the plane in which said lower sides of said spacing studs lies upwards in relation to the plane which the lower edge of said outer framework and said spacer blocks lie.

Preferably said shims are between 8mm and 12mm.

Preferably said method also includes the step of emplacing at least one intertenancy fastener on the upper face of said concrete by pressing attached anchors into said concrete before it sets.

Preferably said method also includes the steps of:

1) assembling a rectangular box frame from a portal head panel, a portal sill panel and two portal wall panels, said head panel and said sill panel located on opposite sides, and connected by said wall panels, the dimensions of said box frame matched with the inner part of a separately preassembled portal frame element, said box frame open at both ends,

2) attaching polystyrene blocks to the outer surfaces of said head, sill and wall panels, the upper edges of said polystyrene blocks overlapping one end of said rectangular box,

3) attaching a PVC barrier sheet to the outer faces of said polystyrene blocks, the lower edge of said barrier sheet substantially aligned with the lower edges of said polystyrene blocks, the upper portion of said barrier sheet overlapping the upper edges of said polystyrene blocks,

4) placing said box, blocks and sheet inside said inner framework, so that said polystyrene blocks face upwards,

5) attaching a plastic barrier block to the outer part of said preassefnbled portal frame element, said barrier block matching the dimensions of the outer part of said preassembled frame element, the outer face of said barrier block offset from the inner face,

6) emplacing said portal frame element so that said inner part rests on the upper edges of said box frame, said polystyrene blocks overlapping the sides of said frame element,

7) attaching said upper portion of said PVC barrier sheet around said barrier block and said frame to form a seal,

8) removing said barrier block once said concrete has been pouted and has cured. In a sixth aspect the invention consists in a wall panel fastener, comprising: a hollow fastening tube, a main body comprising a rod bent to form a panel portion and a connection portion, the connection portion end of said rod attached to the side of said fastening tube, said panel portion spaced from said fastening tube, said panel portion aligned substantially parallel to said fastening tube. Preferably said fastening tube to said connection portion is between 60mm and 200mm, and said fastening tube is between 30mm and 250mm in length.

Preferably said perpendicular distance is between 90mm and 110mm, and said fastening tube is 90mm in length.

Preferably said fastening tube is formed from a 90mm length of NB20 galvanised pipe, and said main body is formed from Dl 0 rio rod.

Preferably said wall panel fasteners embedded within it in such a manner that said at least one fastening tube passes through a first side wall of said first panel, to a separate building element, said first preformed wall panel positioned so that said first side wall is adjacent an outer surface of said separate building element, said method comprising the steps of: 1) using said fastening tube as a drill bit guide and drilling a hole in said separate building element,

2) filling said hole and said fastening tube with a chemical anchor,

3) inserting a bolt in said tube, said bolt fitted with a washer and nut at the outer end to act as a flange on the end of said tube, said bolt sized so that the lower end of said bolt will be within said hole when said outer end is resting on the end of said tube.

Preferably said step of drilling said hole is carried out so that said hole is substantially the same depth as the length of said tube, and said bolt is chosen to be between 120-150% the length of said tube.

Preferably said tube is 90mm long, said hole is 80mm deep, and said bolt is a 120mm Ml 2 bolt.

Preferably said separate building element is a second preformed building panel.

In a seventh aspect the invention consists in a method of using the wall panel fastener as claimed in any one of claims 88 to 91 to connect a first preformed wall panel that has at least one of said wall panel fasteners embedded within it in such a manner that said at least one fastening tube passes through a first side wall of said first panel, to a separate building element, said first preformed wall panel positioned so that said first side wall is adjacent an outer surface of said separate building element, said mediod comprising the steps of: 1) using said fastening tube as a drill bit guide and drilling a hole in said separate building element,

2) filling said hole and said fastening tube with a chemical anchor,

3) inserting a bolt in said tube, said bolt fitted with a washer and nut at the outer end to act as a flange on the end of said tube, said bolt sized so that the lower end of said bolt will be within said hole when said outer end is resting on the end of said tube.

Preferably said step of sealing said PVC sheet is achieved by taping said sheet to said barrier block.

Preferably said method includes the step of emplacing a number of stud elements around said box frame, before said building panel is moulded. Preferably said method includes the step of pre-cutting said barrier block with an angled rebate before it is attached to the outer part of said frame. Preferably said rebate is 5 degrees.

In an eighth aspect the invention consists in a method of casting portal elements into a building panel, comprising the steps of: 1) assembling a rectangular box frame, open at both ends, from a portal head panel, a portal sill panel and two portal wall panels, said head panel and said sill panel located on opposite sides, and connected by said wall panels, the dimensions of said box frame matched with the inner part of a pteassefnbled portal frame element,

2) attaching polystyrene blocks to the outer surfaces of said head, sill and wall panels, the upper edges of said polystyrene blocks overlapping one end of said rectangular box,

3) attaching a PVC barrier sheet to the outer faces of said polystyrene blocks, the lower edge of said barrier sheet substantially aligned with the lower edges of said polystyrene blocks, the upper portion of said barrier sheet overlapping the upper edges of said polystyrene blocks,

4) placing said box, blocks and sheet in a building panel mould, so that said polystyrene blocks face upwards,

5) attaching a pre-cut plastic barrier block to the outer part of said frame element, said barrier block matching the dimensions of the outer part of said preassembled frame element, the outer face of said barrier block offset from the inner face,

6) emplacing said frame element so that said inner part rests on the upper edges of said box frame, said polystyrene blocks overlapping the sides of said frame element,

7) attaching said upper portion of said PVC barrier sheet around said barrier block and said frame to form a seal, 8) moulding said building panel around said box frame and said frame element,

9) removing said barrier block.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described with reference to the accompanying drawings in which;

Figures Ia and Ib show top and side views of a 'standard'-designated embodiment of the wall panel of the present invention.

Figures 2a and 2b show top and side views of an 'extra'-designated embodiment of the wall panel of the present invention. Figures 3a and 3b show top and side views of a 'heavy-duty'-designated embodiment of the wall panel of the present invention.

Figures 4a and 4b show top and side views of an 'extra-heavy-duty'-designated embodiment of the wall panel of the present invention.

Figure 5 shows a side view of an 'intertenancy'-designated embodiment of the wall panel of the present invention.

Figure 6 shows detail of the wall panel fastening device of the present invention.

Figure 7a shows the wall panel fastening device of panel 6 in use, connecting a ground floor wall panel to a foundation plate.

Figure 7b shows the wall panel fastening device of panel 6 in use, connecting a second floor wall panel to a first floor panel located underneath.

Figure 8 shows a perspective view from one end of a prior art ceiling batten manufactured by USG ₅ which is used as part of the construction of several of the preferred embodiments of wall panel.

Figure 9 is a cross-sectional side view of a typical window frame including a window sill and window head, formed using the method and apparatus of the present invention.

Figure 10 is a cross-sectional side view of the standard wall panel including a window, showing detail of a window frame, sill and head formed using the method and apparatus of the present invention.

Figure 11 is a cross-sectional side view of the extra wall panel including a window, showing detail of a window frame, sill and head formed using the method and apparatus of the present invention.

Figure 12 is a cross-sectional side view of the heavy duty wall panel including a window, showing detail of a window frame, sill and head formed using the method and apparatus of the present invention.

Figure 13 is a cross-sectional side view of the extra heavy duty wall panel including a window, showing detail of a window frame, sill and head formed using the method and apparatus of the present invention. Figure 14 shows a top cross-sectional view of two panels connected at their edges to form a mitred corner.

Figure 15 shows an example of a standard wall panel with cast-in windows and doors.

Figure 16 shows an example of how a horizontally aligned element such as a floor panel can be attached to a vertically-aligned wall panel of the type shown in any of Figures 1 to 5, by showing a floor panel connected to an extra wall panel, the extra wall panel having a standard wall panel emplaced above it.

Figure 17 shows a perspective view of an example partial mould layout that can be adapted to produce the panels of Figures 1 to 5.

Figure 18 shows an isometric view of an outer framework used to form a construction panel, having outer walls and spacers positioned within the perimeter of the framework, the spacers having vertically aligned fasteners.

Figure 19 shows an isometric view of the framework and spacers of Figure 18, with a high density polystyrene sheet in position over the top of the spacers, the fasteners protruding

thϊough the sheet, and polystyrene blocks positioned on top of the sheet leaving a network of channels between adjacent blocks.

Figute 20 shows an isometric view of the framework of Figures 18 and 19, with rebar elements added within the outer frame, and the front facing wall not shown for clarity. Figute 21 shows the framework of Figure 20, with concrete being poured into the framework to form the construction panel.

Figute 22 shows an exploded view of the construction panel and outer framework. Figute 23 shows a cutaway side view of the finished construction panel of the preferred embodiment. Figute 24 shows adjacent ends of two construction panels, connected via a pair of corner connector units partially embedded in each panel.

Figute 25a shows adjacent ends of two construction panels used as floor panels, each having an edge that is shaped so as to interlock with the edge of an adjacent panel, the panels located over a floor joist, with one of the panels bolted to the floor joist. Figute 25b shows adjacent ends of two construction panels used as wall panels, each having an edge that is shaped so as to interlock with the edge of an adjacent panel, the shaped edge also allowing the panels to interlock around the end of a horizontal wall stud.

Figute 26 shows an end view of a casting bed for creating the construction panels of Figures 18 to 25.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the invention is susceptible to embodiment in different forms, specific embodiments are shown in the drawings, and described in detail. The present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that as illustrated and described herein.

There are three main aspects to the invention, which are described in detail below: Firstly, improved panel casting methods will be described. Also, the structure of the panels formed by this method.

Secondly, an improved panel construction for fastening pre-cast panels to other panels, foundation slabs, or similar will be described, and the method by which this improved construction can be formed.

Thirdly, an improved method of casting elements such as windows and doors into a preformed panel during the panel forming process will be described. PRE-FORMED PANEL CASTING

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The panel forming methods of the present invention can be used to form panels of a variety of different configurations. A first forming method and the panel created using this method will be described first, with reference to Figures 18 to 26. Then a second general forming method will be described, and five different preferred embodiments of panel configuration which can be formed using the second general forming method, will be described below, with reference to Figures 1 to 5, and 8.

The construction of the panel of the first forming method, and the method of construction, will be described in tandem below.

The general construction method can be broadly outlined as follows: Firstly, an outer frame 5001 of the required overall perimeter size is created using pre-cast or pre-formed outer or side walls 5002, 5003. The side walls are connected together in such a manner that there are no gaps in the perimeter. That is, the outer frame 5001 forms an enclosed perimeter around an inner space. It is usual for this framework 5001 to be created on a factory or warehouse floor or similar. The floor must be reasonably level (that is, substantially horizontal), but does not have to be a completely flat or clean surface. The outer frame 5001 forms the sides of a mould. In the preferred embodiment, the walls 5002, 5003 are used only to form the mould, and do not become part of the final panel. However, other embodiments not specifically described herein may use the side walls as part of the finalised panel. The side walls 5002, 5003 can be of different lengths and sizes, depending on the overall final size of panel required. Next, spacing elements or spacers 5004 are added. These lie inside the outer frame 5001. In the preferred embodiment, the spacers 5004 are steel U-channel beams, placed on their sides within the outer frame 5001 (that is, turned through 90 degrees) so that one side of the beam lies flat on the floor or forming surface, and the open part of the U faces sideways. In the preferred embodiment, the base portion of the 'U' (which is vertical and defines the height of the spacer element when the channel is positioned on its side for use) is 65mm, and each of the side walls is 35mm in length. In the preferred embodiment, the spacers 5004 are laid in parallel rows at intervals of approximately 60mm centre to centre (on centre), with die ends of each spacer 5004 contacting or close to the inner surface of one of the side walls 5002, 5003 of the outer frame 5001. It should be understood that alternative arrangements are possible. For example, more complex 'hash'-type arrangements could be created, rather than simple parallel rows. Alternatively, custom spacers of a required shape (e.g. circular, rectangular, oval etc) could be used. It should also be noted that constructions where window or door frames are moulded into the panel 5012 during this creation phase are possible, and a preferred method by which this casting process can

be carried out will be described in detail below. If window frames or door frames are moulded into the panel 5012, the spacers 5004 are arranged and spaced accordingly.

The upper sides of each of these spacer elements 5004 are fitted with fastening members or fasteners 5005, spaced along the upper side. These fasteners 5005 face substantially vertically upwards. The fasteners 5005 are steel pins or similar, riveted or otherwise connected to the upper side of each channel. In the preferred embodiment, these are approximately 70mm high (or long), and are spaced at intervals along each of the spacers 5004. In the preferred embodiment, there are five or six of the fasteners 5005 spaced at regular intervals along each of the spacing members 5004. In the finalised panel 5012, the steel channel spacer beams 5004 form lightweight inner studs that protrude from the inner surface of the finished panel 5012. The panels 5012 can either be used as house wall panels, with the outer surface forming part of the outer wall of a house, or alternatively, these panels can form floor panels, with the outer surface forming the internal floor of the house. The inner studs or spacers 5004 can be used to attach gib board or similar internal finishing material to the panel 5012, to form the inner wall of a house. The spacers 5004 of the preferred embodiment also have other uses. For example they can be used to route cables between the outer wall (the panel 5012) and the inner wall (the gib board) of a house.

Once the U-beam spacers 5004 have been emplaced in the outer frame 5001, a heavy- duty plastic panel or planar sheet 5006 of plastics material is positioned over the spacers 5004. This sheet 5006 fills the outer frame 5001, and is sized such that it exactly fills the inner space of the outer frame 5001. It should be noted that exactly in this context means that there is a close enough fit between the edges of the sheet 5006 and the walls 5002, 5003 to ensure that wet concrete will not leak through between the two. In the preferred embodiment, the sheet 5006 is 25mm thick polystyrene. The thickness of the sheet 5006 ensures that it is robust and heavy- duty, and will not bend, break or otherwise deform when carrying a heavy weight of wet concrete during the panel forming process.

The sheet 5006 is impaled on the fasteners 5005, with approximately half the overall length of the fasteners 5005 protruding through the upper surface of the sheet 5006.

When 'inner surface' and 'outer surface' of the sheet 5006 for the first forming method are referred to, these have the following meanings: the inner surface of sheet 5006 is the upwardly facing surface during the forming process (it is 'internal' or 'inside' the finished block 5012), and the outer surface of the sheet 6 faces downwards during forming, with the spacers 4 abutting tlie outer surface. It should be noted that for the concrete block formed by this method,

the outer face is the face that will form part of the external building wall when it is in use, and the inner surface of the concrete block or concrete portion of the panel is inside in use.

Once the sheet 5006 is in place, polystyrene blocks 5008 are placed on the sheet 5006. In the preferred embodiment, these are elongate, generally rectangular blocks, having sides 5010 that slope inwards when the blocks are viewed end-on (so that the base, positioned on the sheet 5006, is wider than the topmost face of the block). The preferred height of each block is 50mm, with a base of 500mm and a top surface having a width of 450mm in the preferred embodiment. It should be noted that this is the preferred form, which gives an appropriate mix of insulation and strength. If required, the dimensions of the blocks 5008 can be altered. For example, the base could have a width of between 350mm and 550mm, with the top surface tapering in from this base as appropriate. It should also be noted that the block 5008 does not have to be tapered at all if this is preferred.

In the preferred embodiment, the blocks 5008 are positioned so that they lie in parallel rows, between the parallel rows formed by the fasteners 5005 protruding through the sheet 5006. It is preferred that the gap between the ends of each of the blocks 5008 and the side walls is in the region of 200mm. However, this gap can be altered as required. The blocks 5008 are spaced from one another in rows. It can be seen that elongate trenches are formed between adjacent ones of the blocks 5008. These form stud channels, so that when concrete is poured into the outer frame 5001 in the final panel forming step, the concrete that fills the trenches or stud channels forms concrete studs 5011 which are an integral part of the finished panel 5012. That part of the concrete studs 5011 contacting the sheet 5006, together with the bases of the polystyrene blocks 5008, form a planar inner face that abuts the sheet 5006.

It should be noted that other embodiments are possible. For example, the polystyrene blocks 5008 could be held in place by co-locating or impaling these with the fasteners 5005. However, the preferred embodiment has the advantage that the spacing elements 5004 are co- located with the concrete studs 5011. This provides a visual indication of the location of the concrete studs 5011 to a builder or other worker viewing the finished panel.

Before the final step of pouring concrete is carried out, other desirable elements can be added as required. For example, rebars 5013, wire strengthening grids or similar can be emplaced inside the outer frame 5001, over and around the polystyrene blocks 5008. The preferred embodiment includes reinforcing elements or rebars 5013 laid within the outer frame 5001. In the preferred embodiment, these are parallel with, and located directly above the spacers 5004. The rebars 5013 are also positioned so as to be located at or around the same height as the upper surface of the polystyrene blocks 5008.

As shown in Figure 23, the outet frame 5001 can be fotmed with at least one of the side walls at an angle from the vertical. A panel 5012 having this feature can be useful in certain constructions. For example, if two adjacent blocks have complimentary angled faces (for example each face angled at 45 degrees), these can be connected to form the corner of a house wall, as shown in Figure 24.

As shown in Figures 25a and 25b, the corners can be moulded into other shapes if required. Figure 25a shows two adjacent panels 5012, where the adjacent edges have been shaped so that the adjacent panels interlock over a floor stud 5100. A bolt 5101 in the floor stud is used to attach at least one of the panels to the stud 5100. Figure 25b shows a similar interlocking arrangement, where the mutual edges of two adjacent panels have been shaped to allow the panels to interlock, and also so that the panels can interlock with a wall joist 5200 or similar, so that the wall joist 5200 becomes partially embedded in, and supported by, the wall formed by the panels.

In order to aid with this connection process, other elements can be added when forming the inner frame 5007, as required. For example, a corner connector. Before the concrete is poured, the corner connector is positioned over the polystyrene blocks 5008 and rebars 5013. A part of this corner connector protrudes from the side of the outer frame 5001, so that after the concrete is poured, it protrudes from the edge of the panel 5012. This connector can be angled at e.g. 45 degrees, so as to fit flush with a similar connector on an adjacent panel, with for example apertures (not shown) passing through the exposed part to allow the use of bolts (not shown) or similar to connect adjacent panels 5012.

As noted above, other elements can also be added as required — for example door or window framing elements. If a panel with this mix of elements is required, the polystyrene blocks 5008 and other insert elements are shaped appropriately, for example, being shorter elements to fit around the door and window framing elements.

Once the required mix of elements is in place within the outer framework 5001, the final step of pouring concrete into the framework 5001 to form the panel 5012 takes place. Concrete is poured over the top of the polythene sheet 5006, the polystyrene blocks 5008, and any other additional, optional elements which are present, such as the rebars 5013 or the connectors 5014. In the preferred embodiment, the total depth of concrete poured should be about double the height of each of the polystyrene blocks 5008. The poured concrete has a flat upper surface, which forms the outer or outwards facing surface of the wall panel 5012 once it has hardened.

Once this concrete has dried and hardened sufficiently, the outer framework 5001 can be removed and the panel 5012 is ready for use and transport as required.

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For the first preferred forming method, a casting bed 5300 can be used to create multiple panels of the type described above. The casting bed 5300 allows the creation of multiple moulds, with concrete poured into these multiple moulds either simultaneously or sequentially, to create a plurality of panels. Multiple moulds allows a number of panels of different construction to be created simultaneously. The casting bed is described below. CASTING BED

The preferred embodiment of casting bed is shown from one end in Figure 26. Four I- beams 5301 are laid in parallel. The beams 5301 can be as long as is required. For example, if a large number of panels 5012 are required (requiring a large number of moulds), the I-beams could be 100 meters in length, with a number of moulds spaced along the length of the beams 5301. Sections of the outer framework 5001 are placed on these I-beams and bolted together to form as many separate moulds as are required. It can be seen that the spacing between the two outer I-beams 5301a will dictate the dimensions of one edge (e.g. the width) of the panel 5012. In the preferred embodiment, the two outer beams 5301a are spaced apart approximately 2770mm (measured from the vertical part of each beam), to form a panel 5012 or set of panels 5012 of this width (less 2x the wall thickness of the outer frame 5001 on each side). The two inner I-beams 5301b are placed inside the two outer I-beams 5301a, spaced parallel and equidistant between the outer beams 5301a. Sections of outer framework 5001 are laid parallel to and crossways to the I-beams 5301 to form the moulds, the I-beams 5301 providing a stable platform for the outer framework sections. It should be noted that in the embodiment described above, the outer walls of the frame 5001 are placed on the outer two of the I beams 5301. However if required, one or both, of the walls of the frame 5001 could be moved in to one of the inner I beams. It should also be noted that the spacing of the inner I beams can be altered if required. Once the concrete has been poured into the moulds and allowed to solidify, the outer framework sections can be unbolted and removed.

This arrangement has the advantage of allowing several concrete pours to take place either simultaneously or sequentially (pouring into each sub-frame in turn) without requiring a break in construction to reposition elements or create another, separate outer frame. Second General Forming/ Casting Method

The second general forming/casting method is similar to the fkst method described above. A number of elements are assembled to form an open-topped mould, into which concrete is poured to form a panel 2000. The panel 2000 formed in the mould is aligned

hotizontally, and after the concrete is cured, the panel is lifted and rotated through 90 degrees so that it is vertical, ready for use.

To form the outer perimeter or outer framework of the mould, a pair of perpendicular bracing members are laid out parallel to one another, on an appropriate surface. This can be any flat, clean surface, and is usually a surface such as a factory or warehouse floor, or similar. A pair of parallel bracing members are connected to the perpendicular bracing members so that the connected perpendicular and parallel members form the outer walls of a hollow structure. In the preferred embodiment, the members are aligned vertically, and one of the parallel bracing members, member 6, is attached to the perpendicular bracing members so that it is angled outwards at 45 degrees (the bottom edge being further in towards the centre of the structure dian the top edge). The bracing member 6 could be angled at any required angle between vertical and horizontal. However, the preferred embodiment of a 45 degree angle produces cast concrete panels that can easily be butted together with other similar panels to form 90 degree corners, without complicating building logistics. It can be seen that the width of the panel will depend on the depth of concrete pour, and therefore the width of the members. A minimum panel depth (width in use) of 200mm is preferred, and the members are sized accordingly.

As described above, the parallel bracing members interlock with the perpendicular bracing members to form the closed outer perimeter of the mould. In the preferred embodiment, the ends of all the bracing members are interlocked. However, any of the members could overhang the connected members, as long as they are all connected to form a closed structure overall. In the preferred embodiment, the mould is rectangular, so that a rectangular building panel 2000 will be formed once concrete is poured. The 200mm minimum height of the closed structure formed by the bracing members allows a minimum width of building panel formed in the mould to be 200mm. That is, once concrete is poured, the panel will be 200mm wide (or deep). It could of course be made wider by pouring a greater depth of concrete.

Polystyrene spacer blocks 7, 8, 9 are laid out against two of the sides of the rectangular mould, so that their outer edges are flush with the inner surfaces of the bracing members 3, 4, 5, 6. These polystyrene blocks are arranged parallel to one another — paraEel spacer blocks 7 and 8 - on opposite sides of the mould. It is preferred that blocks 7 and 8 run the full length of the inside of the mould, with their first ends fitted snugly against the inner face of member 3, and their second ends fitted snugly against the inner face of member 4. However, if required, the blocks 7, 8 could run from the inner face of one of the members and stop short of the inner face of the opposite member. In some embodiments, a perpendicular spacer block 9 is fitted perpendicular to blocks 7, 8, with each end of block 9 sized and shaped to fit snugly between the

adjacent first ends of blocks 7, 8, so that spacer blocks ate arranged around three sides of the mould. A timber top plate 10 is laid along the fourth side of the mould, with its outer edge against the inner surface of the adjacent perpendicular bracing member 4, and the ends of the timber top plate 10 fitting between the adjacent second ends of the blocks 7, 8. The timber top plate 10 is aligned parallel to polystyrene block 9 on die other side of the mould. The polystyrene blocks 7, 8, 9 and the timber top plate 10 form a hollow rectangle or square inside the perimeter of the mould. If polystyrene block 9 is not present, the polystyrene blocks 7, 8 and the timber top plate 10 form a U-shape in plan. It is preferred that the ends of the timber top plate 10 Lie between the second ends of the blocks 7, 8. That is, the timber top plate 10 does not run the full width of the mould, although this is not a critical feature of the construction. If block 9 is not present, when the concrete is poured, it is poured directly onto the flat surface at that point.

Each of the parallel polystyrene blocks 7, 8 are 50mm thick (depth), and have a width of 150mm. The perpendicular block 9 is 39mm thick (depth), and has a width of 90mm. The timber top plate 10 has a thickness (depth) of 45mm, and a width of 145mm. A 23mm service channel or service conduit 20 is placed on top of the timber top plate

10. The conduit forms a channel on top of the timber top plate 10. In die preferred embodiment, a ceiling batten manufactured by USG, and well-known in the construction industry, is used. This is emplaced with the open side facing towards the timber top plate 10. The profile of the preferred USG ceiling batten is shown in Figure 8. The preferred form of ceiling batten used has a depth of 23mm, and the flat base has a width of 37mm. It is preferred that the conduit 20 is nailed to the plate 10 to hold it in position. The service channel 20 runs the length (end to end) of the timber top plate 10.

Outer spacing studs, Ia, Ib, Ic, Id are placed in the mould, around the perimeter of the hollow rectangle formed by the polystyrene blocks 7, 8, 9 and the timber top plate 10, so that the lower portions of the studs la-d lie against the flat surface (e.g. factory floor). The studs can also be shimmed so that the lower surface lies 10mm above die flat surface of the factory floor. If a window is cast into the panel, this allows a window jamb to be set on the factory floor, and GIB™ board or drywall can be inserted into the jamb. On other style windows, the jamb may lie flush with the drywall or pass below the drywall. In the preferred embodiment, the studs 1 are square U-channel metal beams, with the base of the U-channel aligned vertically. The upwards- facing side or surface of the U-channel includes a number of fastening elements or fasteners 2. In the preferred embodiment, these are vertically aligned elongate metal elements, fastened at intervals along the length of the upper face of the stud 1. The spacing studs can be quickly and easily created from standard U-beam sections, attaching the fasteners to one side of the U-beam

by pin spotting or instant welding, of any other suitable attachment method. There is no need to cast these fasteners into a concrete stud.

In the most preferred embodiments, the four outer spacing studs la-Id form a closed perimeter around the outside of the hollow square, and face inwards as described above. The vertically aligned 'base' of each of the outer U-channels Ia — Id is aligned with, and flush against, the inner edge of the adjacent polystyrene block — blocks 7, 8, and 9, and the timber top plate 10. Alternatives to this arrangement shall be described in more detail in the 'extra heavy duty' section below.

In the preferred embodiment, due to the 45 degree angle of member 6, the polystyrene block 8 has its outer face or side cut at an angle of 45 degrees so that it will fit flush against the inner face of the parallel bracing member 6. In the preferred embodiments, the width of block 7 is 150mm, and the width of the upper (or wider) face of the angle-cut block 8 is 150mm.

Fastening bolts 90 are inserted towards each end of each of the blocks 7, 8, protruding upwards from the blocks 7, 8. The lower ends of the bolts 90 pass through the polystyrene to a point where the ends are 5mm shallower or 5mm less depth than the lowest point on the studs 1. The upper ends of the fastening bolts 90 protrude upwards from the upper face of the polystyrene blocks 7, 8. In the preferred embodiments, the bolts 90 are 130 M12 studs. The function of these bolts 90 shall be described in greater detail below.

The timber top plate 10 includes vertically aligned anchor screws 11, protruding upwards, one at each end, passing through the full depth of the top plate 10, and the service conduit 20.

One or more central studs Ic is added in parallel with the studs Ia and Ie, running the length/height of the hollow rectangle between the studs Ib and Id, against the timber top panel 10 and the polystyrene block 9.

An example of a mould with elements similar to those described above arranged inside the perimeter is shown in Figure 17. The example mould is shown with two of the outer side walls or bracing members not present, so that details of the inner layout can be seen. It should also be noted that the elements which are arranged inside the mould are not shown in their correct proportions or dimensions, and the layout shown is for example purposes ^" only, and does not correspond to any of the specific layout examples described below, which are used to produce the preferred embodiments of wall panels.

A plastic or polystyrene sheet 12 is laid over the top of the studs Ia - Ie. The sheet 10 is sized so that it just covers the studs 1. That is, it is the same size and dimensions as the hollow rectangle in the centre of the mould. The two ends of the sheet 10 that face towards the parallel bracing members 7, 8 are flush with the vertical portions of the outer studs Ia — Id to form a

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continuous vertical surface. The polystyrene sheet 12 is 50mm thick in most of the preferred embodiments. However, it is thinner in some alternative embodiments, as will be described in detail below.

When 'inner surface' and Outer surface' of the polystyrene sheet 12 for the second forming method are referred to, these have the following meanings: the inner surface of sheet 12 is the upwardly facing surface during the forming process (it is 'internal' or 'inside' the finished concrete panel), and the outer surface of the sheet 12 faces downwards during forming It should be noted that as for the first forming method, the outer face of the blocks formed is the face that will form part of the external wall or surface of the building wall it is in use, and the inner surface of the concrete block or concrete portion of the panel is inside in use.

A steel mesh and reinforcing bars can be added to the mould, arranged so that they are spaced above the polystyrene sheet, but below an upper pour level of concrete when this is added to the mould. That is, so that they will be embedded in the concrete once it is poured.

Once this mix of elements has been assembled, concrete is poured into the framework over the top of all the elements within the mould. Where required, other elements can be added to the wet concrete from above as will be described in further detail below. Once the concrete has set or cured, the bracing members 3, 4, 5, 6 are removed. The general wall panel 2000 is now ready to be lifted into the vertical position and moved to wherever it is needed.

It can be seen that there will be a concrete 'overhang' around the perimeter of the panel 2000 formed as described above. That is, the central part of the concrete panel over the top of the polystyrene sheet 12 will be less thick than the edge portions. This overhang forms a boundary portion or edge wall that runs around the perimeter of the panel. As the panel is rectangular, there will be four sides to the perimeter portion. Each of the four sides will have a flat inner face, and these faces will be at different depths through the panel, as the timber top plate and polystyrene blocks 7, 8, 9 are different thicknesses or depths. The flat inner face on each side will be the same width as the spacer or top plate to which it is adjacent. The parallel spacer blocks will lie against first and second sides on opposite sides of the panel — parallel to one another. The timber top plate will lie against the forth side, and in the embodiment where the perpendicular spacer block is used, this will lie against the third side. When aligned for use, the concrete portion of the building panel 2000 will have an inner face, surrounded by the boundary portion, and a smooth outer face. The inner face of the concrete portion will be adjacent to the inner face of the polystyrene sheet, which fully covers the inner face of the concrete portion. The inner side of the building panel will be planar, with the inner faces of the spacer blocks, the

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timber top plate and the inner side of the spacer studs all lying in the same plane, unless the spacing studs are shimmed as described above.

It should be noted that some of the dimensions of certain elements have been specified above — for example widths and depths of certain elements have been specified, but the lengths have not. Standardised widths and depths allows elongate items to be sourced and cut to lengdi as required — for example, an elongate length of polystyrene having a 50mm x 150mm cross section. The lengths of the items can be varied as required to produce panels of the required overall size. That is, the required length for a specific layout can be cut from a source piece of standard width and depth. Also, using studs formed from steel channels allows flexibility in the layout and dimensioning of the wall panels, and keeps the overall weight of the panel down.

As at least one side or end of the panel can be produced at an angle — e.g. a 45 degree angle — the corners of the panels can be connected together at 90 degrees to form mitred corners. An example of two standard panels 100 with a 90 degree mitred corner is shown in Figure 14. To connect the two panels in this manner, the 45 degree angled corners are brought together so that the faces of the panels 100a and 100b are aligned at 90 degrees. The bolts 90a and 90b are embedded in the polystyrene during the forming process — panels 107a and 107b, and before the panels 100a and 100b can be connected, the polystyrene around the ends of the bolts is scraped and cut away. A right angle bracket 190 is placed in the corner, with the heads of the bolts 90a and 90b protruding through apertures in the bracket 190. In the preferred embodiment, the bracket is a lOOxlOOxόmm RSA. Nuts 191a and 191b are threaded onto the bolts 90a and 90b to hold the bracket 190 in place, and to hold the panels 100a and 100b together. Drywall boards 192 are added to finish the internal faces of the room. The bolts 90 can also be used to attach horizontally aligned elements to the vertically aligned wall panels. For example, flooring panels. An example of this connection is shown in Figure 16, where a horizontally-aligned floor panel 3000 is connected to a vertically aligned 'extra' panel 200, which has a vertically aligned 'standard' panel 100 connected to its upper edge. The panel 3000 is connected to the panel 200 by means of bolts 90 passing through apertures in an angle-bracket 3001 which is connected to the floor panel 3000, the bolts 90 and bracket 3001 held in place by nuts.

The mould internal elements formed as described above can be assembled and then transported with the elements in place to e.g. a building site, with the outer frame of the mould formed, and concrete poured, on site. For example, the mould internal elements can be assembled in one country, and then shipped in shipping containers to another country where the concrete is poured. The internal elements of the mould are the spacing studs, the polystyrene

elements, and the timber top plate. The outer framework could also be included in die shipped elements, if required.

Specific embodiments of the panels of the invention shall now be described with reference to Figures 1-5. The five panel embodiments described below are designated as 'standard', extra', 'heavy-duty', 'extra-heavy-duty', and 'intertenancy'. Standard Panel

The standard wall panels 100 are intended for the construction of single storey buildings, and the top floor of multi storey buildings. The standard panels 100 can also be used as external cladding (non-structural and non-weight bearing) e.g. on a high rise. A plan view of a standard panel 100 is shown in Figure 1 (during manufacture of the panel, this would be a cross-sectional side view).

In the standard wall panels, there are three parallel U-section studs 101a, 101c and lOle, arranged in parallel so that when the panel 100 is in use, they will be aligned vertically. Each of these is a steel channel having a 90mm width. The U-sections of the outer two studs 101a and lOle face inwards, and these are completely filled with polystyrene 150. The polystyrene 150 is held in place in place by the upper edges or lips of the U-beam, which are angled inwards. The polystyrene 150 can be added to the U-beam before the lips are angled inwards, or a length can be pushed in from one end. The central U-section 101c is empty. Two further studs 101b, 101d are arranged perpendicular to studs 101a, 101c, 101Oe, across the ends of the studs 101a, 101c, 1010e. Studs 101b and 101d are also filled with polystyrene 150.

A polystyrene sheet 112 is located above the studs 101 and is held in position by the fasteners 102 on the studs 101. The polystyrene sheet 112 has a standard thickness of 50mm as described above.

The fasteners 102 are 75mm long/high. The parallel polystyrene blocks 107, 108 have a standard tiiickness of 50mm as described above.

The timber top plate 110 has a width of 145mm along its length, and a thickness of 45mm, as described above.

The polystyrene block 109 has a width of 90mm, and a thickness of 39mm, as described above.

As described above, steel mesh and reinforcing bars are also added.

Once these elements are arranged in the mould, concrete 170 is poured so that the panel has an overall depth (or width in use) of 200mm. It is preferred that concrete with a compressive

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sttength of 40 MPA is used in the standard panel 100. It can be seen that the depth of the concrete over the polystyrene sheet 112 will be 60mm. Extra Panel

The extra wall panel 200 shown in figure 2 is constructed in a very similar manner to the standard wall panel, but it is intended to be used in situations where a greater thickness of concrete is needed. That is, where a greater degree of structural strength is required. For example, the ground floor of a two storey building, the second floor of a three-storey building, and single storey buildings in increased risk building zones such as coastal areas or areas of greater seismic activity. The timber top plate 210, parallel polystyrene blocks 207, 208, and the polystyrene block

209 are as used in the standard panel 100. The polystyrene sheet 212 is also the same, with a thickness of 50mm.

The studs 201a-201e are 64mm width steel channels. The fasteners 202 are 75mm long/high. The polystyrene 250 in the channels of the studs 201 does not completely fill the channels. It fills the upper third of the channel when they are aligned for the pour (outer third when the panel is aligned for use). These polystyrene lengths 250 are glued in place in the channels.

Concrete 270 is poured to create an overall panel width of 200mm, as in the standard panel 100. However, as the studs are 64mm, and not 90mm, the concrete depth over the polystyrene sheet 212 is greater than that of the standard panel and is 86mm. It is preferred that concrete with a compressive strength of 40 MPA is used in the extra panel 200. The finished extra panel 200 is thicker and stronger than the standard panel 100. Heavy Duty Panel The construction of the heavy duty panel 300 is similar to the standard and extra constructions described above. The heavy duty panel 300 is intended for use in constructing the first floor of a three storey building, or the wall of a commercial building, or as an over- engineering option (that is, the heavy duty panel 300 can be used in situation where a standard panel 100 or an extra panel 200 would probably be sufficient, but the risk is minimised by using the heavy duty panel 300). As before, the concrete is poured to create an overall panel depth of 200mm.

The constructional differences are as follows:

The steel channels used for the studs 301a, 301b, 301c are 51mm wide, and a thinner polystyrene sheet 312 is used, having a thickness of 30mm. As the studs 301 are shorter, and the

polythene sheet 312 is thinner, the depth of concrete 370 over the polystyrene sheet 312 is greater at 119mm. It is preferred that concrete with a compressive strength of 40 MPA is used in the heavy duty panel 200. The finished heavy duty panel 200 is thicker and stronger than the extra panel 200 and the standard panel 100. It should also be noted that no polystyrene is included inside the channels of the studs

301. Extta Heavy Duty Panel

The construction of the extra heavy duty panel 400 is very similar to the panels 100, 200, 300 described above. The extra heavy duty panel is intended to be used to form basement walls, or retaining walls, or the lowest floor of a multi-storey building. The constructional differences are as follows:

The studs 401 are formed from trapezoid or box profile pipe USG battens, the same as are used to form the service conduits. The depth (height) of the studs is 23mm. The thickness of the polystyrene sheet 412 is 25mm. The studs are arranged in parallel rows, and do not form a closed perimeter.

Also, the perpendicular spacer block 9 is removed or not emplaced at all, so the concrete on that side of the panel, when poured, reaches all the way to the flat surface or floor.

Concrete 470 having a compressive strength of 40MPA is poured to form a panel 400 having an overall width of 200mm as before. The thickness of the concrete 470 over the polystyrene sheet 412 is 151mm.

Due to the dimensions of the studs 401, the polystyrene sheet 412 and the spacer blocks, the lower (or inner) edges of the polystyrene sheet overlap with the outer or upper edges of the spacer blocks and the timber top plate. Inteitenancy

Intertenancy walls are used to divide up internal spaces within multi-occupancy buildings, and are used where a greater degree of strength is required than can be provided by a frame and drywall arrangement. There may be other considerations that dictate the use of a concrete intertenancy wall, for example sound damping between apartments or similar. Also, concrete intertenancy walls provide a better fire barrier than walls constructed from other materials — e.g. wooden framing and drywall.

Intertenancy panels 500 can be constructed using the method described above. They are formed from the same mix of elements as the standard panel 100. However, intertenancy panels 500 do not generally have one side face angled at 45 degrees, as their ends are generally

connected perpendicular to the inner face of an external wall. Therefore, support member 6 is aligned vertically when forming the mould, and not at 45 degrees, so that both ends of the panel 500 are squared off.

It should also be noted that the outer face of the panels 100-400 is formed from the upper surface of the poured concrete. As this is intended as the outer face when the panel is emplaced as part of a building, an unfinished concrete surface is acceptable. However, occupants generally prefer drywall for internal walls. Also, the space between the concrete wall and the internal drywall can be used to run cables or similar. Therefore, when forming the intertenancy panel 500, once the wet concrete has been poured, spacers are pressed into the concrete before it sets. In the preferred embodiment, the intertenancy spacers 560 are USG ceiling battens, the same as those used to form the service conduits, and are emplaced with the open side facing towards the wet concrete, with anchors 561 protruding downwards into the concrete. When the intertenancy panel is emplaced, the spacers 560 are used to fasten up drywall panels in a similar manner to the studs 1, the studs 1 and the spacers 560 allowing drywall to be added to both sides of an internal wall. The flat base of the USG channel provides a flat surface suitable to screw drywall boards onto.

In all the embodiments described above, the wall panel is standardised at 2.4m (interior drywall measurement) with an overall height of 2.545m.

If extra height is required — e.g. for a 2.7m high wall (interior drywall measurement), the building panel has an overall height of 2.845 high. This wall is formed by using the same steel track frame to form the spacer studs as is used for the 2.4m, but an additional 300mm high rectangle of steel track and stud is added between the top of the 2.4m steel track spacing studs, and the timber top plate. A 50mm polystyrene sheet and reinforcing is also added on top of this rectangle, just like the regular wall (the size of the spacing studs and polystyrene sheet depends on the size of wall required). The additional rectangle is screwed to the bottom of the timber top plate prior to either concrete pouring or shipping. If the wall is shipped, this is done in two parts - a 2400mm bottom section and a 445mm top section. On arrival, the 445mm rectangle/top plate/reinforcing assembly is screwed to the top of the 2400mm bottom stud assembly, and the concrete poured to form the panel. PRE-CAST PANEL FASTENING

The apparatus for fastening pre- formed building panels together, and the method of fastening building panels in place using the improved apparatus, will now be described with reference to Figures 6 and 7.

As has been described in the prior art section, wall panels are normally formed with a number of apertures cast into the top edge of a building panel - for example, the top edge of a ground floor external wall panel (these could also be machined into the top edge post-casting). A number of complimentary fastening elements are set into the lower edge of e.g. a first floor panel, extending downwards. As described, the tolerance ranges in this prior art fastening method are critical, as the embedded fastening elements and the apertures must align.

The fastening apparatus of the present invention removes the need for elements to be cast into the building panels within a tolerance range, so that they align with another set of elements in a separate panel. A preferred embodiment of wall panel fastening device 600 is shown in Figure 6. The fastening device 600 has a main body 601 and a connected fastening tube 602. The main body 601 is formed from DlO tio rod, bent through 90 degrees partway along its length to form a panel portion 603 and a connection portion 604. The fastening tube 602 is formed from a 90mm length of NB20 galvanised pipe, so that the ends can be aligned with the edges of the panel 9 (90mm width in the preferred embodiment). The fastening tube 602 is connected (by welding or similar) to the connection portion end 605, approximately halfway along the length of die outside of the fastening tube 602, so that the fastening tube 602 is aligned parallel to the panel portion 603. In the preferred embodiment, the connection portion 604 is approximately 104mm long, from the end 605 to the centre line of the panel portion 603 (perpendicular distance from the side of the fastening tube 602 to the centreline of the panel portion 603). The length of the wall panel portion 603 can be adjusted to suit the stud height when the fastening device 600 is emplaced.

In use, a number of the fastening devices 600 are cast into panels - e.g. panels 100, 200, 300, etc. The fastening devices 600 are aligned so that when they are emplaced in the mould, each of the outer ends 606 are located against the adjacent support member that forms the wall of the mould, with the side of the fastening tube 602 resting on top of the panel 9. Wall panel portion 603 is located above and parallel with the top surface of the polystyrene sheet 12. When the concrete is poured, the depth of the concrete ensures that the wall panel portion 603 is fully submerged and embedded. When the supporting members that form the mould are removed, the outer end 606 is flush with the lower edge of the wall panel and the inner end can be accessed from the inwards- facing part of the wall panel. The fastening tube 602 passes all the way through the lower edge wall of the wall panel. That is, the lower part of the boundary portion, edge wall or perimeter portion that runs around the perimeter of the panel. In use, the wall panel is lifted into position,

fot example a standard wall panel 100 is lifted into position on the foundation slab 1000 of a bungalow, as shown in Figure 7a. The outer face of the wall panel 100 is aligned as required with the foundation slab. As the outer ends 606 of the embedded fastening tubes 602 are flush with the lower edge, there is no need to pre-form apertures in the foundation slab, and the need for pre-formed apertures to match up with protruding members on the lower edge of the building panel 100 is removed. To attach the building panel 100 to the foundation slab, a user (e.g. a construction worker) moves to the inside face of the building panel 100, once it has been positioned. The user, equipped with a masonry drill, locates the drill bit into the inner end of the fastening tube 600, using it as a guide for the drill bit, and drills downwards to create a hole 620 in the foundation slab (which will be aligned with the fastening tube 602) . The depth of the hole 620 is approximately the same as the length of the fastening tube 602 — 90mm. The hole depth should be sufficient that there is some overlap with the reinforcing mesh and bar in the panel. The hole 620 and the fastening tube 606 are filled with a chemical anchor 630 such as Ramset™ chemset capsules. An M12 bolt 618 is then pressed into the top of the fastening tube 606, down into the hole 620, activating the chemset capsules. The top end of the bolt has a nut 617 and washer 619 pre-fitted to act as a flange, with the washer resting in position on the top of the tube 606, keeping the bolt 618 in position until the chemset is solid. It is preferred that the body of the bolt is at least 120mm long, so that there is at least a 120mm embedment.

A similar fastening arrangement is shown in Figure 7b, where the lower edge of a second floor building panel (e.g. a standard panel 100) is positioned on the top edge of a first floor building panel (e.g. an extra panel 200). The drilling and positioning of the bolt 618 and chemset 630 are the same as described above with reference to Figure 7a. The cross-section of extra panel 200 also shows the steel mesh 240 and reinforcing bars 250 that are added to the mould before the concrete is poured, to add strength to the structure. The panel attachment method and apparatus used when attaching panels 100, 200, 300,

400, 500 to each other or to other elements is very similar to that outlined above with reference to Figures 7a and 7b.

CASTING ELEMENTS INTO A PANEL DURING THE PANEL FORMING PROCESS The method and structure by which elements such as complete window assemblies and door assemblies can be cast into a building panel during the panel forming process shall now be described with particular reference to Figure 9. Assemblies such as window assemblies or door assemblies can generally be referred to as portal elements. Preferred embodiments of the standard panel 100, extra panel 200, heavy duty panel 300 and extra heavy duty panel 400,

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including cast-in windows formed using the method described, are shown as cross-sectional side views in Figures 10-13.

In the preferred embodiment^), the casting method is used to cast windows, with the window glass already in place, directly into a wall panel of the type(s) described above, during the wall panel casting process.

A cross-section of the general wall panel 2000 is shown in Figure 9. The wall panel 2000 with the window cast in, is formed in the same overall manner as the general panel casting method. That is, a number of elements as required to form the finished product are added to a mould framework formed from outer parallel and perpendicular members 3, 4, 5, 6. Elements are added inside this outer framework, around the edges — e.g. blocks 7, 8, 9, timber top plate 10, studs 1, etc. The window will be located reasonably centrally, so it will not interfere with any of these elements located close to the edges.

To form the finished window, firstly an open-ended rectangular box is formed from the wooden window framing elements. As shown in Figure 9, the window has an upper wooden head panel 801, and a lower wooden sill panel 802, both arranged so that when the panel is aligned for use, they will be horizontal. The head 801 and the sill 802 are connected by vertical timber side wall panel portions (not shown) to form the rectangular box. The size of the rectangular box frame will be dictated by the required size of the window. Windows can come in standard sizes, but are normally custom-tailored depending on the builder's or end-user's requirements. Before the timber frame sill, head and sides are cut to length, the size of the window frame element needs to be known. This information determines the size of the rectangular frame, which is matched with the window frame or door frame (frame elements). The emplacement of the window frame 805 will be described in detail below.

Once the rectangular box is formed, by gluing or nailing the timber head 801, sill 802 and sides together, 10mm polystyrene window blocks 804 are then glued to the outer sides or surfaces of the head 801, sill 802 and timber wall sections. The width of the window blocks 804, and their location, is such that they do not reach all the way to the inner or lower edges of the head 801, sill 802 and side walls. The lower edges of the polystyrene blocks 804 are located about halfway down the head 801 and sill 802. A PVC barrier sheet 803 is then glued in place on the outside of the blocks 804, with the lower edge of the sheet 803 aligned with the lower edge of the blocks 804 (although this alignment is not strictly necessary for the forming method). Alternatively, the sheet 803 can be added to the blocks before they are glued to the wooden frame. The PVC sheet 803 is sized so

that it can overhang the top of the polystyrene blocks 804 by approximately the same length again as the blocks 804.

This assembly — the head 801, sill 802 and side walls, plus the polystyrene blocks 804 and the barrier sheet 803 is placed where requited in the mould. A set of inner studs Ib are then arranged around the outside of each of the head 801, sill

802, and the timber window frame side walls. The studs Ib face outwards, with their bases pressed up against the PVC barrier 803 on die outer face of the window blocks 804. The studs Ib are sized and preformed to fit the known size of window frame for that particular panel type and window size. The polystyrene sheet 12 is then pressed down onto the fasteners 2 protruding upwards from the studs 1. The polystyrene sheet 12 has a central aperture pre-cut into it so that it will fit snugly against the outer sides of the polystyrene window blocks 804. This can easily be achieved if the window frame dimensions are known, by adding 10mm to each of the sides to give the overall dimensions of the aperture. The blocks 804 are sized so that when the polystyrene sheet is in place, they stand slightly proud of the top surface of the polystyrene sheet 12.

The preformed or preassembled window frame 805 has a barrier block 807 added to it before it is emplaced. The barrier block 807 is exactly cut to size, to fit the individual frame. This is achieved in the preferred embodiment by placing the frame onto a 30mm thick sheet of polystyrene while the frame 805 is still separate from all the other items, so that the outer edges of the frame 805 are on the surface of the polystyrene. The outline of the frame 805 is then marked onto the polystyrene. The polystyrene is then cut to shape, with a -5 degree negative rebate, so diat the inner face 808 and the outer face 809 of the barrier block 807 are offset from one another. That is, the upper and lower ('in use' alignment) sides 810 and 811 of the barrier block 807 are angled downwards at an offset of 5 degrees from horizontal, as shown in Figure 9. The barrier block 807 is taped (e.g. using duct tape or similar) to the outer part of the frame 805. Duct tape is also added to the frame around all the exposed portions.

The preformed or preassembled window frame 805, including glass 806, and with the barrier block 807 taped in place, is then inserted into the central space formed by the four window blocks 804 (two side blocks, and an upper block and a lower block). In the example embodiment shown, the window frame 805 is an extruded aluminium frame produced by

Fairview windows. As can be seen in Figure 9, the frame 805 is narrower on the inner part than the outer part (inner and outer referring to 'in use' alignment), with a lip 850 resting on the perimeter formed by the polystyrene blocks 804, and the inner part - the lower or inner edge 860 — resting on the upper (outer) edge of the timber portions. It can be seen that the polystyrene

window blocks surround the intersection where the lower edge of the window frame 805 rests on the upper edge of the box frame formed from the timber portions. Once the frame 805 is in place, the 'spare' portion of the PVC sheet 803 is then folded up to help shield the frame 805 from concrete slurry or similar during the pour. The concrete 70 is then poured into die mould to form the panel 2000, flowing over the top of the sheet 12, and around the emplaced frame 805. The PVC sheet 803 acts as a barrier to stop the concrete slurry touching the frame. The barrier block 807 stops the concrete slurry flowing across the top of the frame.

Once the concrete has cured, the barrier block 807 can be cut out from the panel, and a panel with a window, including glass, cast in place, has been formed.

Door frames can be cast into the panels in the same manner.

An example of a standard panel 100 adapted to include cast-in windows and doors is shown in Figure 15. The adaption of the pattern of the internal studs Ic can clearly be seen.