OA11215A

OA11215A - Modular sandwich panel and method for housing construction

Info

Publication number: OA11215A
Application number: OA9900245A
Authority: OA
Inventors: Gazal Nabil Nasri
Original assignee: Gazal Nabil Nasri
Priority date: 1997-05-08
Filing date: 1999-11-05
Publication date: 2003-07-17
Also published as: CN1103402C; AP1073A; ID29312A; WO1998050646A1; NZ500989A; AP9901691A0; CN1260020A; KR20010012388A

Abstract

A composite panel (1) comprising at least two spaced apart outer laminates (2, 3) and a core laminate (4) sandwiched therebetween. The outer laminates (2, 3) and the core laminate (4) are off-set such that portions (5, 6) of the outer laminates protrude beyond the core by a predetermined margin (A) along a first edge of the panel and such that the core laminate (4) protrudes beyond the outer laminates by a generally corresponding margin (B) along an opposite edge (7) of the panel. The protruding portions of the outer laminates of one panel are adapted nestingly to receive and locate a complementary protruding core portion of an adjacent like panel in interlocking relationship to form a composite panel assembly.

Description

01121 5 -1 -

TITLE: MODULAR SANDWICH PANEL AND METHOD FOR HOUSINGCONSTRUCTION

FIELD OF THE INVENTION

The présent invention relates to composite building panels, and also to a 5 construction system using such panels.

The invention lias been developed primarily for use in the building industry as part of a modular housing construction system. It will be appreciated, however, that theinvention is not necessarily limited to this particular field of use.

BACKGROUND OF THE INVENTION 10 In conventional housing construction, walls are fabricated by first erecting a structural frame which is usually formed ffom timber. The frame is subsequently cladinternally with a suitable laminate material such as plaster board or gyprock, which isthen finished to conceal joins and finally painted. The external wall is normally formed either from brick veneer, or a suitable cladding material which is also fastened to the 15 timber frame. Common external cladding materials include weatherboard, fibre reinforced cernent, and aluminium. Roofing normally consists of corrugated iron or tiles, again arranged on a timber, framework.

This conventional construction technique is particularly labour intensive and costly, for a number of reasons. For example, many skilled workers from numerous 20 specialised trades such as builders, brick layers, carpenters, joiners, tilers and plasterersare required, ail of which add considerably to the overall cost. Conventional techniquesalso rely heavily on valuable and diminishing material resources, especially timber, which gives rise to increasing costs as supplies become less available. Moreover, conventional housing must essentially be built on site, according to architectural plans. -2- 011 21 5

There is little scope for pre-fabrication or modular construction, and minimal flexibility for restructuring a house in a cost effective manner, once built. Furthermore,if a house is to be demolished, there is little opportunity for recycling or reusing theconstituent materials, which are therefore largely wasted. A further disadvantage with 5 conventional techniques is that the finished structure offers minimal Sound and heat insulation. This often needs to be addressed later, for example by the addition ofinsulation batts in the roof cavity, at additional cost.

Current building techniques also produce structures which are relatively heavy, particularly where bricks, roof tiles and timber frames are involved. Because of the 10 weight associated with these materials, the supporting structures must in turn be relatively large and robust, which adds further weight. The end resuit is that manylightweight materials which may otherwise be suitable, do not possess sufficient strengthto be used in conjunction with conventional housing construction techniques.

In an attempt to ameliorate some of these problems, Steel framed houses hâve 15 been proposed. It has been found in practice, however, that the résultant cost-benefit is at best marginal, and most of the fundamental problems remain.

In a further attempt to address these problems, the use of composite panels has also been proposed. Such panels typically incorporate a sériés of layers or laminatesfabrïcated front a variety of materials to achieve desired strength to weight 20 characteristics, insulation properties, and the like. A major problem with known fabrication techniques, however, is that there is a practical limit to the maximum size of individual panels. This in turn has led to various techniques for joining smaller panels to form composite panel assemblies of the required size. In the past, however, inadéquate 011215 -3- techniques for joining the panels hâve resulted in such structures being relatively weak.The résultant loss of structural integrity has meant that in practice, the potential strengthto weight characteristics offered by composite panels hâve not been able to be realised inlarge scale applications, including housing in particular. For this reason, in the past, 5 composite panels hâve typically only been used to form internai partitions and non-load-bearing walls, where significant structural integrity is not required. As such, the fundamental problems associated with conventional building methods hâve remained unsolved. Hence, there is a long felt need to a more efficient and cost-effective alternative to existing housing construction techniques. 10 It is an object of the présent invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

DISCLOSURE OF THE INVENTION

Accordingly, in a first aspect, the invention as presently contemplated provides a composite panel comprising at least two spaced apart outer laminates and a core laminate 15 sandwiched therebetween, the outer laminates and the core laminate being off-set such that portions of the outer laminates protrude beyond the core by a predetermined marginalong a first edge of the panel and such that the core laminate protrudes beyond the outerlaminates by a generally corresponding margin along an opposite edge of the panel, whereby the protruding portions of the outer laminates of one panel are adapted 20 nestingly to receive and locate a complementary protruding core portion of an adjacentlike panel in interlocking relationship to form a composite panel assembly, saidcomposite panel further including a generally U-shaped channel member which forms a -4- 011215 stud configurée! for interlocking engagement with a complementary edge of an adjacentlike panel to form said composite panel assembly.

In the preferred embodiment, the generally U-shaped channel member covers theprotruding portion of the core laminate to form a stud. The channel member is 5 preferably defined by spaced apart flanges and an intermediate web disposed such thatthe flanges lie parallel to and immediately inside the respective outer laminates along thecorresponding edge of the panel and the web extends between the flanges to cap theprotruding portion of the core laminate. The channel member is preferably disposedsuch that the flanges extend marginally between the core laminate and the respective 10 outer laminates. In this way, the channel member is adapted to be pressed into position and is generally self-locating.

The channel members are preferably pressed from sheet métal and are oriented in use to form vertically extending studs between adjacent wall panels, thereby providing structural integrity for the composite wall. ] 5 In an alternative configuration, the channel member may be disposed on the opposite side of the panel with the flanges inserted between the protruding portions ofthe outer laminates and the web spaced outwardly, away from the core laminate. In this configuration, the channel member protrudes beyond the outer laminates to define a tongue formation similar to the protruding core on the opposite side of the panel, and at 20 the same time fonns a longitudinal cavity or duct bounded by the recessed edge of the core laminate, the channel flanges, and the channel web. This cavity may be used for concealed routing of building services such as electrical cables, water pipes, télécommunication lines, and the like. - 5 -

In a first preferred form of the invention, the core laminate is formed from expanded polystyrène foam with one outer laminate being formed from plywood and theother outer laminate being formed from plasterboard or gyprock. This embodiment ofthe invention is particularly suitable for use as an external wall, with the plywood layer 5 facing outwardly to receive a final weatherproof finish in situ. Preferably, in thisconfiguration, a layer of expanded Steel mesh is stapled to the plywood laminate.

Cernent render is then applied such that the expanded Steel mesh layer acts asreinforcing for the cernent. A final protective coat of paint may then be applied. Theinternai plasterboard or gyprock layer is preferably finished to conceal join lines and 10 painted, in the conventional manner.

In a second preferred form of the invention, both the outer layers may be formed from gyprock or plasterboard. Panels manufactured according to this configuration are particularly suitable for use as internai walls or partitions, where weatherproofing is not required. 15 In the various embodiments of the invention described above, the outer laminates are preferably secured to the core laminate by means of a cross-linking polymer adhesive.

In one preferred embodiment, adjacent panels are secured in overlapping tongueand groove relationship by at least one fastener, extending through an outer laminate of 20 one panel, through a flange of the channel member or stud and into the core laminate ofthe adjacent panel, thereby securing the adjoining panels and the intermediate studtogether. Preferably, a line of spaced apart screw fasteners extend along the overlappingedges of each adjacent pair of panels. -6- 011215

In a third preferred form of the invention, the foam core laminate may besandwiched between outer layers of sheet métal. This arrangement is particularly well adapted for use as a roof panel. Preferably, the internai laminate is formed from fiat sheet métal whilst the extcrnal laminate is formed from corrugated sheet métal to 5 provide increased strength, improved water run-off, and a conventional corrugated ironappearance. Ridge capping strips, eaves, trimming strips, guttering and the like may be fitted as required.

According to a second aspect, the invention provides a method of forming a composite panel, said method comprising the steps of sandwiching a core laminate 10 between spaced apart outer laminates such that portions of the outer laminates protrudebeyond the core by a predetermined margin along a First edge of the panel and such thatthe core laminate protrudes beyond the outer laminates by a generally corresponding margin along an opposite edge of the panel, providing a generally U-shaped channel member which fonns a stud for interlocking engagement with a complementary edge of 15 an adjacent like panel, whereby the protruding portions of the outer laminates of one panel are adapted nestingly to receive and locate a complementary protruding core portion of an adjacent like panel in interlocking relationship to form a composite panel assembly.

According to a third aspect, the invention provides a building structure 20 comprising internai and external walls, each being formed as an interlocking composite panel assembly substantially as defined above.

Preferably, the building structure further comprises a roof formed as an interlocking composite panel assembly as previously defined, A generally U-shaped 011215 -7- capping strip is preferably placed along the upper marginal edges of the wall panels toprovide additional structural strength and to facilitate fastening of the roof panels.

According to a fourth aspect, the invention provides a method of building ahousing structure comprising the steps of forming externat walls, forming internai walls, 5 and forming a roof, each from a sériés of inter locking composite panels substantially asdefined above, and fastening the respective panels together to form a stable housing structure.

Preferably, the housing structure is adapted to be assembled on a concrète slab.

In this case, the lower marginal edge of the external outer laminate of each wall panel 1 o preferably extends downwardly beyond the core laminate and the internai laminate to define a right angled rebate adapted to rest along a corresponding edge portion of theconcrète foundation slab. Preferably also, fasteners such as "dyna-bolts" are placed to extend through the external outer laminate and into the side of the foundation slab to prevent the housing structure from lifting in high wind conditions. In the preferred 15 embodiment, a weatherproof flashing strip is positioned between the foundation slab and the overlying wall panels.

BRIEF DESCRIPTION OF TIIE DRAWINGS

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: 20 Figure 1 is a perspective view showing a composite panel, for use as part of an external wall in a housing structure according to the invention;

Figure 2 is a perspective view showing the external wall panel of Figure 1, with the outside layer finished with expanded Steel mesh reinforcing and cernent rendering; -8- 011215

Figure 3 is a cutaway plan view showing a pair of panels according to Figures 1and 2, interlocked and fastened together in tongue and groove relationship to form acomposite panel assembly according to the invention;

Figure 4 is a perspective view showing the reinforcing channel member or studof the panels of Figures 1 and 2;

Figure 5 is a perspective view showing a composite panel similar to that shown in Figure 1, adapted for use as part of an internai wall according to the invention;

Figure 6 is a plan view showing the use of a stud positioned in reverse orientationto connect adjacent panels in female to female relationship and thereby to define a concealed duct for service lines;

Figure 7 is a cutaway perspective view showing a composite panel adapted for use as part of a roofing assembly according to the invention;

Figure 8 is a cutaway perspective view showing a composite panel adapted for use as a structural beam according to the invention;

Figure 9 shows the use of a saddle bracket adapted to mount the beam. of Figure 8 to an abutting wall panel;

Figure 10 shows a double sided saddle bracket adapted to mount structural beamsin coaxial alignment on opposite sides of an intermediate wall panel;

Figure 11 is a cross-sectional detail showing a method of mounting the external wall panels to a concrète foundation slab according to the invention;

Figure 12 is a front élévation showing the mounting detail of Figure 11;

Figure 13 is a plan view showing a wall to wall corner detail according to the invention; -9- 011215

Figure 14 is a cross sectional view showing a wall to roof fastening methodaccording to the invention; and

Figure 15 is a front élévation showing a housing structure fabricated fromcomposite panels according to the invention.

5 PREFERRED EMBODIMENT OF THE INVENTION

Referring firstly to Figures 1 to 4, the invention provides a composite panel 1 comprising two spaced apart outer laminates 2 and 3, and a core laminate 4 sandwichedtherebetween. The outer laminates and the core laminate are offset such that respectiveedge portions 5 and 6 of the outer laminates protrude beyond the core by a 10 predetermined margin A along a First edge of the panel. Similarly, an edge portion 7 ofthe core laminate protrudes beyond the outer laminates by a generally correspondingmargin B along the opposite edge of the panel. This arrangement of laminates defines a tongue and groove configuration whereby the protruding portions 5 and 6 of the outer laminates of one panel are adapted nestingly to receive and locate the complementary 15 protruding core portion 7 of an adjacent like panel in interlocking relationship to form acomposite panel assembly, as shown in Figure 3, and described in more detail below.

In one preferred embodiment, the core laminate 4 is formed from expanded polystyrène foam, betwcen 20mm and 100mm, and ideally around 50mm to 60mm thick.

In the embodiment shown in Figure 1, the outer laminate 2 is formed from plywood 20 around 3mm thick and the other outer laminate 3 is formed from plasterboard or gyprock, and is around 10mm thick. The outer laminates are bonded to the core with a spécial purpose cross-linking polymer adhesive suitable to the purpose. This form of - 10- 011215 panel is particularly suitable for use as an external wall, with the plywood layer facingoutwardly to receive a weatherproof finish. A preferred form of external finish is shown in Figure 2, whereby a sheet ofexpanded steel mesh 10 is stapled to the plywood laminate and subsequently covered 5 with a layer of cernent rendering 11. In this way, the steel mesh acts as reinforcementfor the rendering. A final protective coat of weatherproof paint is then applied. Theinternai plasterboard or gyprock layer is filled to conceal the join lines, finished and finally painted in the conventional manner, well known to those skilled in the art.

In the preferred embodiment depicted, a generally U-shaped channel member 15 10 covers the protruding portion of the core laminate 4, so as to form a stud. It should beappreciated, however, that an alternative configuration is possible wherein the U-shapedchannel member is located within the recess formed along the opposing edge of the panel by the protruding edge portions 5, 6 of the outer laminates.

As best seen in Figure 4, the channel member or stud 15 is defined by spaced 15 apart flanges 16 and an intermediate web 17 with a longitudinally extending rebate 18for added strength. It should be noted that the intermediate web may be discontinuous;that is, it may include one or more apertures, perforations or the like along its length.Once in position, the flanges 16 lie parallel to and immediately inside the respectiveouter laminates 2 and 3 along the corresponding edge of the panel whilst the web 17 20 extends between the flanges to cap the protruding portion 7 of the core laminate. The flanges extend marginally between the core laminate and the respective outer laminates so that, once pressed into position the stud is generally self-locating, although adhesive is preferably also used. - 11 - 011215

In the alternative configuration, the U-shaped channel member 15 is positioned inthe recess formed along the opposing edge of the panel and such that the web 17 is located in proximity to the core laminate, whilst the flanges 16 are positioned inside theouter laminates 2, 3 and extend outwardly from the recess. 5 The channel members 15 are pressed from sheet métal and oriented in use such that, in a wall, the studs extend vertically between adjacent panels to provide structural integrity.

In the preferred form of the invention, the standard sizes for external wall panelsrange from approximately 900 mm in width, 2500 - 4000 mm in height and 65 - 90 mm 10 in depth. It will be appreciated, however, that the panels may be fabricated in any desired size or shape, depending upon the intended application and production capabilities. Once produced the panels may be eut down as required, for example to accommodate Windows, doors, beams, roof panels, and other fittings, without loss of structural strength. 15 Figure 5 shows a variation on the panel of Figure 1, wherein both outer layers 2 and 3 are substantially identical and are formed from gyprock or plasterboard. Panels manufactured according to this configuration are particularly suitable for use as internai walls, where weatherproofing is not required.

Figure 6 shows an alternative form of assembly whereby the protruding edges 520 and 6 of a pair of panels are butted together in female to female relationship and an additional channel member or stud 15 is positioned in between such that the channel web is spaced apart from the core laminate of one of the panels. In this reverse configuration, the channel member protrudes beyond the outer laminates of the left hand panel (when - 12- 0 3 1215 viewing the drawing) to form a tongue in a manner similar to the protruding core portionon the opposite side of the panel. In this way, the left side panel engages the right sidepanel in tongue and groove relationship. At the same time, the stud forms a longitudinal cavity or duct 20 bounded by the recessed edge of the core laminate of the left side 5 panel, the channel flanges, and the channel web. This cavity may be used for concealedrouting of building services such as electrical cables, water pipes, télécommunicationUnes, and the like without the need for any separate routing processes or additional materials, and without weakening the structure as a whole.

As best seen in Figure 3, adjacent panels are fixedly secured in overlapping tongue 10 and groove relationship by a sériés of screw fasteners 21, each extending through an outer laminate of one panel, through the adjacent flange of the channel member or stud, and into the underlying core laminate of the adjoining panel, thereby firmly securing thepanels together. A line of screw fasteners thus extend along the adjoining edges of eachadjacent pair of panels. The panels are further secured by a top capping strip 22 which 15 also serves to cover and seal the top surfaces of the wall panels and to provide additional overall structural integrity. The capping strip is best illustrated in Figures 9, 11 and 14.

Figure 7 shows a further variation wherein a specially shaped foam core laminate 4 is sandwiched between outer layers 2 and 3 of sheet métal, the upper layer 2 beingcorrugated to provide increased strength, improved water run-off and a conventional 20 aesthetically pleasing appearance. This arrangement is particularly well adapted for use as a roof panel 24 since, being essentially self-supporting, it obviâtes the need for a roofframing structure other than a central support beam as described below. - 13 - 011215

Figure 8 shows how the basic éléments of the panel System may be adapted to form a high strength and extremely light weight structural beam 25. The beam is thus formed as an elongate composite panel comprising identical outer laminates 2 and 3 formed from plywood, preferably 3mm in thickness, sandwiching a core laminate 45 formed from expanded polystyrène foam, preferably 50mm in thickness as per the panels described above. The same cross-linking polymer adhesive is used to adhéré the laminates together. A pair of channel members 15 are respectively disposed along the top and bottom faces of the beam, to provide additional bending strength. The chamiels also act as capping strips to seal and protect the relatively soft foam core laminate. It has 10 been found that this beam provides adéquate strength to support a composite panel roofing structure as described above, without the requirement for supplementary framework or trusses, and without adding significantly to the overall weight or cost of the building.

Figure 9 shows the use of a saddle bracket 26 used to anchor the structural beam 15 25 of Figure 8 to a vertical wall panel. The saddle bracket is eut and folded from a straight length of 90° angled sheet métal as shown, using a suitable template or jig. It isthen hooked over the upper edge of the wall panel in the appropriate location, andsecured into position with screw fasteners, some of which extend into the top métal capping strip 22, and some of which extend directly into the panel, ideally into a vertical 20 stud to give direct metal-metal engagement between these primary structural éléments.

This arrangement provides adéquate support for the structural beam, without theneed to eut slots, recesses or rebates into the wall panel itself. This substantiallyexpedites the construction process without compromising structural integrity. A similar -14- 011215 double-sidcd saddle bracket 27 may be used, if the structural beam is effectively tocontinue from the opposite side of the wall panel, as would often be the case with internai walls. This is best illustrated in Figure 10.

Figure 11 shows how in building and housing construction applications, the wall5 panels are fastened to a concrète foundation slab 30. The concrète slab is fîrst poured tothe appropriate dimensions using conventional formwork techniques. The lower surface of each external wall panel is rebated, such that the lower marginal edge 31 of the external laminate 2 of each panel extends downwardly beyond the core laminate 4 and the internai laminate 3 by a margin C. The résultant 90° rebate allows the panel to rest 10 along the outer edge of the foundation slab, with the lower edge 31 of the outer laminate providing positive and accurate latéral positioning. A correspondingly shaped flashing strip 32 is then laid along the edge of the slab for weather-proofing, as well as to seal and protect the lower surfaces of the panels. The wall panels are then positioned as shown inFigure 11 such that the flashing strip is tightly sandwiched between the rebates of the 15 panels and the corresponding edge of the slab. At this stage, the wall panels are secured in position by dyna-bolts 34 or similar fasteners, which extend through the lower edge31 of the outer laminate, and directly into the slab through pre-drilled pôles.

Where adjacent wall panels join, a métal anchor strip 35 is used. As best seen in

Figure 12, the lower end 36 of the anchor strip is positioned so as to overlie the outer20 vertical face of the foundation slab, whilst the upper end 37 of the strip overlies the wall panels and more particularly the vertical stud 15. In this way, a lower fastener such as adyna-bolt 34 extends through the lower end 36 of the anchor strip, through the loweredges 31 of the outer laminates, and thence into the slab, The upper fasteners 21 extend - 15 - 011215 through the upper end 37 of the anchor strip, through the outer laminates of the adjacentpanels, through the underlying stud, and into the core. By this means, the entire panelassemblies, and not merely the outer laminates, are anchored directly to the foundation slab. Moreover, the studs are disposed to transfer load directly frorn the walls and the5 roof to the concrète foundation. It has been found that this anchoring method provides a structure capable of withstanding extreme weather conditions, including cyclonic wind loadings, which would demolish rnany structures built in accordance with conventional techniques.

Figure 13 shows an enlarged corner detail, illustrating how the wall panels 1 are 10 abutted together at a 90° corner, and joined by means of an angled métal corner strip 40.Each face.of the corner strip is screw fastened where shown into the underlying stud of the corresponding panel to cover the join line and to provide additional structural strength.

Figure 14 shows a preferred arrangement for securing an inclined roof panel 24 15 to a vertical wall panel 1, by means of respective internai and external angle brackets 43 and 44. As shown in the drawing, screw fasteners are used to secure the lower face ofeach bracket 43 and 44 to the top capping strip and elsewhere on the wall panel whilstthe upper face of the angled bracket is screw fastened to the underside of the roof panel.

The join line is covered and sealed internally by means of cornice whilst an 20 external cover strip (not shown) may also be provided for thermal insulation and weather protection.

Turning now to describe briefly the method of constructing a house or other building in accordance with the présent invention, the concrète foundation slab 30 is First -16- 011215 layed using conventional form work techniques. The flashing strip 32 is then positionedaround the periphery of the foundation slab. The external wall panels 1 are then positioned such that the outer edge of the concrète slab nests in the rebate with the lower edge 31 of each panel extending downwardly over the outer edge of the slab. The wall 5 panels are then secured to the slab with dyna-bolts 34 or similar fastening éléments, and anchor strips 35 are secured into position across the joints between adjacent panels. At this stage, the screw fasteners 21 are installed along the overlapping edges of each adjacent pair of panels. The corners are then joined using corner strips 40, as shown inFigure 13. The upper edges of the wall panels are then covered and sealed by the U- 10 shaped capping strips 40, as shown in Figures 9 and 11, which adds further structural integrity to the panel assembly. Window and door frames are eut from the wall panels asrequired, and finished with framing éléments formed from timber or aluminiumextrusions, as required. At this stage, the external wall structure is complété, save forfinishing which will be described below. 15 Next, the main roof beam, of the type shown in Figure 8, can be added by means of saddle brackets 26 and 27 of the type shown in Figures 9 and 10 respectively. Roofpanels 24 of the type shown in Figure 6 are then added, as shown in Figure 14. The roofstructure is finished with a capping strip 50 and guttering 51, as shown in Figure 15.

Internai walls are then formed as required, using interior wall panels of the type 20 shown in Figure 5. Again, spaces for internai Windows and doors are eut from the panelsand framed as required. The internai joints between the plaster board sheets associatedwith the discrète panels are concealed and finished using conventional plasteringtechniques, and finally painted. Skirting and cornices may also be added as required to - 17- 011215 conceal floor-wall and wall-roof joints, for added weather protection, and to provide aconventional aesthetic appearance.

The exterior panels may be weatherproofed and finished as desired. A particularlypreferred form of finishing, however, involves the step initially of stapling expanded 5 Steel mesh sheeting 10 to the exterior plywood laminate 2, and subsequently applying alayer of cernent render 11, within which the expanded steel mesh acts as reinforcement.

The render is fmally painted, to give the appearance of a conventional cernent rendered brick veneer dwelling.

Advantageously, a house, factory or other building manufactured in accordance 10 with the présent invention can be completed in a small fraction of the time involved using conventional building techniques, and at an even smaller fraction of the cost.

Because the structure is so light, less elaborate foundations and structural framing are required, which further reduces material and labour costs. Because the entire set ofpanels may be pre-fabricated off site, the building can be erected with minimal use of 15 skilled labour, further reducing costs. Because of the laminate construction of the panels, and in particular the substantial polystyrène foam core, the building inherently possesses thermal and acoustic insulation properties far superior to those exhibited byconventional buildings, again without the use of additional resources such as fibreglass batts or the like. Because of the unique way in which the panels are anchored to the20 concrète foundation slab, the structure is particularly résistant to wind loadings, even under cyclonic conditions. A further advantage offered by structures built in accordancewith the présent invention is that of flexibility in design. Even after the structure hasbeen completed, internai as well as external walls may be added, removed or changed as - 18- 011215 required, without being constrained by an underlying frame work as is the case in conventional structures.

Furthermore, an entire house may be disassembled, packed away, transported toanother site and subsequently rebuilt with considérable ease. Even in the event that a 5 dwelling is to be entirely demolished, the individual panels and other components maysiroply be re-used in a new project with virtually no wastage of raw materials.

Many of the above advantages flow from the fact that the panels in accordance with the présent System provide their own inhérent structural integrity and thus the

System as a whole avoids the need altogether for a separate frame work. It will thus be 10 appreciated that the invention provides practical and commercially significant improvements over the prior art.

Although the invention has been described with reference to spécifie examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

1. A composite panel comprising at least two spaced apart outer laminates and a core laminate sandwiched therebetween, the outer laminates and the core laminate being off-set such that portions of the outer laminates protrude beyond the core by a predetermined 5 margin along a first edge of the panel and such that the core laminate protrudes beyond the outer laminates by a generally corresponding margin along an opposite edge of the panel, whereby the protruding portions of the outer laminates of one panel are adaptednestingly to receive and locate a complementary protruding core portion of an adjacentlike panel in interlocking relationship to form a composite panel assembly, said composite 10 panel further including a generally U-shaped channel member which forms a stud configured for interlocking engagement with a complementary edge of an adjacent like panel to form said composite panel assembly.

2. A composite panel according to claim 1, wherein said channel member covers theprotruding portion of the core laminate so as to form a stud. 15

3. A composite panel according to claim 1 or claim 2, wherein said channel member is defined by spaced apart flanges and an intermediate web disposed such that the flangeslie parallel to and immediately inside the respective outer laminates along thecorresponding edge of the panel and such that the web extends between the flanges to capthe protruding portion of the core laminate. 20

4. A composite panel according to claim 3, wherein the channel member is disposed such that the flanges extend marginally between the core laminate and the respective outerlaminates whereby the channel member is adapted to be pressed into position and is substantially self-locating. -20- 011215

5. A composite panel according to any one of daims 1 to 4, wherein the channelmember is pressed from sheet métal and is oriented in use to form a generally verticallyextending stud between adjacent panels, thereby providing additional structural integrityfor the composite panel assembly when used to form a composite wall. 5

6. A composite panel according to claim 3, wherein the channel member is disposed on the opposite side of the panel with the flanges inserted between the protruding portionsof the outer laminates and the web spaced outwardly away from the core laminate, in a reverse orientation.

7. A composite panel according to claim 6, wherein the channel member in the 10 reverse orientation protrudes beyond the outer laminates to defïne a tongue formation similar to the protruding core on the opposite side of the panel for engagement with a like panel, and at the same time forms a longitudinal cavity bounded by the recessed edge of the core laminate, the channel flanges and the channel web, the cavity being adapted to facilitate concealed routing of building services. 15

8. A composite panel according to any one of the preceding daims, wherein the core laminate is formed from expanded polystyrène foam, wherein one outer laminate is formed from plywood, and wherein the other outer laminate is formed from plasterboard.

9. A composite panel according to claim 8, wherein the panel is adapted for use as an external wall, with the plywood layer facing outwardly to receive a weatherproof finish in 20 situ.

10. A composite panel according to claim 9, further including a layer of expandedSteel mesh applied to the outer plywood laminate, and a layer of cernent render applied to the steel mesh, such that the Steel mesh acts as reinforcement for the cernent render. -21 - 011215

11. A composite panel according to claim 10, further including a final protective coat of paint applied to the cernent render to produce a substantially weatherproof finish.

12. A composite panel according to claim 11, wherein the internai layer ofplasterboard is filled and finished to conceal join lines. 5

13. A composite panel according to any one of daims 1 to 7, wherein the core laminate is formed from expanded polystyrène foam and wherein both outer layers are formed from plasterboard.

14. A composite panel according to claim 13, being adapted for use as an internai wall or partition. 10

15. A composite panel according to any one of the preceding daims, wherein the outer laminates are secured to the core laminate by means of a cross linking polymer adhesive.

16. A composite panel according to any one of the preceding daims, whereinadjoining panels of a panel assembly are secured in overlapping tongue and grooverelationship by at least one fastener, said fastener extending through an outer laminate of 15 one panel, through a flange of the channel member and into the core laminate of theadjacent panel, thereby securing the adjoining panels together.

17. A composite panel according to claim 16, wherein a linear array of spaced apart screw fasteners extend along the overlapping edges of each adjacent pair of panels.

18. A composite panel according to any one of the preceding daims, wherein the core 20 laminate is between 20 mm and around 100 mm in thickness.

19. A composite panel according to claim 18, wherein the core laminate is formedfrom expanded polystyrène foam and is between 50 mm and around 60 mm in thickness. -22- 011215

-19- 011215 CLAIMS:-

20. A composite panel according to any one of the preceding claims, wherein the panel is approximately 600 mm to 1200 mm in width, 2500 mm to 4000 mm in height and 65 mm to 90 mm in depth.

21. A composite panel according to claim 1, comprising a foam core laminate 5 sandwiched between outer layers of sheet métal.

22. A composite panel according to claim 21, being adapted for use as a roof panel.

23. A composite panel according to claim 22, wherein the internai outer laminate is formed from substantially fiat sheet métal and wherein the external outer laminate is formed from corrugated sheet métal to provide increased strength, improved water run 10 off, and a conventional corrugated iron appearance.

24. A composite panel according to claim 22 or claim 23, wherein an assembly of interlocking roof panels is fitted with ridge capping strips, eaves and guttering as required.

25. A building structure comprising internai and external walls, each being formed as an interlocking composite panel assembly substantially as defined in any one of claims 1 15 to 24.

26. A building structure according to claim 25, further including a roof formed as an interlocking composite panel assembly substantially as defined in any one of claims 1 to 24, said roof being supported by a structural beam formed as an elongate composite panel.

27. A building structure according to claim 26, wherein the structural beam is formed20 from a core laminate formed from expanded polystyrène foam, outer laminates formed from plywood, and capping strips formed from generally U-shaped channel members tocover the exposed longitudinal edge portions of the core laminate. -23- 011215

28. Λ building structure according to claim 27, wherein the structural beam is anchored to a vertical wall panel by means of a saddle bracket, the saddle bracket beingeut and folded from an initially straight strip of angled sheet métal, thereby obviating theneed for slots, recesses or rebates in the wall panel. 5

29. A building structure according to any one of daims 25 to 28, wherein generally U- shaped capping strips are positioned along the upper marginal edges of the wall panels toprovide additional structural strength for the walls and to facilitate fastening of the roof panels thereto.

30. A building structure according to any one of daims 25 to 29, wherein the structure 10 is adapted for assembly on a concrète foundation slab.

31. A building structure according to claim 30, wherein the lower marginal edge ofthe external outer laminate of each wall panel extends downwardly beyond the core laminate and the internai laminate to defme a substantially right angled rebate adapted to rest along a corresponding edge portion of the concrète foundation slab. 15

32. A building structure according to claim 31, further including fastening éléments extending through the external outer laminate and into the foundation slab to prevent the structure from lifting in adverse weather conditions.

33. A building structure according to claim 32, wherein the wall panels are fastened to the foundation slab by means of “dyna-bolts”. 20

34. A building structure according to any one of the daims 30 to 33, further including a weatherproof flashing strip positioned between the foundation slab and the overlying wall panels. -24- 011215

35. A method of forming a composite panel, said method comprising the steps ofsandwiching a core laminate between spaced apart outer laminates such that portions ofthe outer laminates protrude beyond the core by a predetermined margin along a fïrst edgeof the panel and such that the core laminate protrudes beyond the outer laminates by a 5 generally corresponding margin along an opposite edge of the panel, providing a generally U-shaped channel member which forms a stud for interlocking engagement witha complementary edge of an adjacent like panel, whereby the protruding portions of theouter laminates of one panel are adapted nestingly to receive and locate a complementaryprotruding core portion of an adjacent like panel in interlocking relationship to form a 10 composite panel assembly.

36. A method of forming a building structure, comprising the steps of forming cxternal walls, forming internai walls, and forming a roof, each from a sériés ofinterlocking composite panels, each panel being formed substantially in accordance withthe method of claim 35, and comprising the furthcr step of fastening the respective panels 15 together to form a stable housing structure.

37. A method according to claim 36, comprising the further step of assembling the housing structure on a concrète foundation slab.

38. A method according to claim 37, comprising the further step of forming the lowermarginal edge of the external outer laminate of each wall panel so as to extend 20 downwardly beyond the core laminate and the internai laminate, and thereby defining asubstantially right angled rebate adapted to rest along a corresponding edge portion of the concrète foundation slab. -25- 011215

39. A method according to claim 38, comprising the furlher step of installing fastening éléments so as to extend through the outer laminate and into a side of thefoundation slab, thereby to prevent the housing structure from lifting in adverse weather conditions. 5

40. A method according to claim 39, wherein said fastening éléments are “dyna- bolts”.

41. A method according to claim 40, including the further step of positioning aweatherproof flashing strip between the foundation slab and the overlying wall panels.