AU725624B2 - Modular sandwich panel and method for housing construction - Google Patents

Description

WO 98/50646 PCT/AU98/00330

-I-

TITLE: MODULAR SANDWICH PANEL AND METHOD FOR HOUSING

CONSTRUCTION

FIELD OF THE INVENTION The present invention relates to composite building panels, and also to a construction system using such panels.

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

BACKGROUND OF THE INVENTION In conventional housing construction, walls are fabricated by first erecting a structural frame which is usually formed from timber. The frame is subsequently clad internally with a suitable laminate material such as plaster board or gyprock, which is then 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 timber frame. Common external cladding materials include weatherboard, fibre reinforced cement, 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 specialised trades such as builders, brick layers, carpenters, joiners, tilers and plasterers are required, all of which add considerably to the overall cost. Conventional techniques also 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.

WO 98/50646 PCT/AU98/00330 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 the constituent materials, which are therefore largely wasted. A further disadvantage with 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 of insulation 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 weight associated with these materials, the supporting structures must in turn be relatively large and robust, which adds further weight. The end result is that many lightweight materials which may otherwise be suitable, do not possess sufficient strength to be used in conjunction with conventional housing construction techniques.

In an attempt to ameliorate some of these problems, steel framed houses have been proposed. It has been found in practice, however, that the resultant 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 series of layers or laminates fabricated from a variety of materials to achieve desired strength to weight 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, inadequate PCT/AU98/00330 Received 15 February 1999 -3- [AMENDED PAGE] techniques forjoining the panels have resulted in such structures being relatively weak.

The resultant loss of structural integrity has meant that in practice, the potential strength to weight characteristics offered by composite panels have not been able to be realised in large scale applications, including housing in particular. For this reason, in the past, s composite panels have typically only been used to form internal partitions and non-loadbearing walls, where significant structural integrity is not required. As such, the fundamental problems associated with conventional building methods have remained unsolved. Hence, there is a long felt need to a more efficient and cost-effective alternative to existing housing construction techniques.

It is an object of the present 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 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 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 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, said composite panel further including a generally U-shaped channel member which forms a 0 AMENDED SHEET

IPENAIAU

-3astud configured for interlocking engagement with a complementary edge of an adjacent like panel to form said composite panel assembly.

Unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

In the preferred embodiment, the generally U-shaped channel member covers the protruding portion of the core laminate to form a stud. The channel member is o* o* oooo 2* go go ooo :2222 :2222 .:2222 Oooo oo Document4 WO 98/50646 PCT/AU98/00330 -4preferably defined by spaced apart flanges and an intermediate web disposed such that the flanges lie parallel to and immediately inside the respective outer laminates along the corresponding edge of the panel and the web extends between the flanges to cap the protruding portion of the core laminate. The channel member is preferably disposed such that the flanges extend marginally between the core laminate and the respective 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 metal and are oriented in use to form vertically extending studs between adjacent wall panels, thereby providing structural -integrity for the composite wall.

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 of the 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 the same time forms 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, telecommunication lines, and the like.

In a first preferred form of the invention, the core laminate is formed from expanded polystyrene foam with one outer laminate being formed from plywood and the other outer laminate being formed from plasterboard or gyprock. This embodiment of the invention is particularly suitable for use as an external wall, with the plywood layer WO 98/50646 PCT/AU98/00330 facing outwardly to receive a final weatherproof finish in situ. Preferably. in this configuration, a layer of expanded steel mesh is stapled to the plywood laminate.

Cement render is then applied such that the expanded steel mesh layer acts as reinforcing for the cement. A final protective coat of paint may then be applied. The internal S plasterboard or gyprock layer is preferably finished to conceal join lines and 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 internal walls or partitions. where weatherproofing is not required.

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 tongue and groove relationship by at least one fastener, extending through an outer laminate of one panel, through a flange of the channel member or stud and into the core laminate of the adjacent panel, thereby securing the adjoining panels and the intermediate stud together. Preferably, a line of spaced apart screw fasteners extend along the overlapping edges of each adjacent pair of panels.

In a third preferred form of the invention, the foam core laminate may be sandwiched between outer layers of sheet metal. This arrangement is particularly well adapted for use as a roof panel. Preferably, the internal laminate is formed from flat sheet metal whilst the external laminate is formed from corrugated sheet metal to PCT/AU98/00330 Received 15 February 1999 -6- [AMENDED PAGE] provide increased strength, improved water run-off, and a conventional corrugated iron appearance. 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 between spaced apart outer laminates such that portions of the outer laminates protrude beyond the core by a predetermined 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, providing a generally U-shaped channel lo member which forms a stud for interlocking engagement with a complementary edge of 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 comprising internal 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 capping strip is preferably placed along the upper marginal edges of the wall panels to provide additional structural strength and to facilitate fastening of the roof panels.

AMENDED SHEET

FEAI.AU

PCT/AU98/00330 Received 15 February 1999 6a [NEW PAGE] According to a fourth aspect, the invention provides a method of building a housing structure comprising the steps of forming external walls, forming internal walls, and forming a roof, each from a series of interlocking composite panels substantially as AMENDED SHEET

IPEA/AU

WO 98/50646 PCT/AU98/00330 -7defined above, and fastening the respective panels together to form a stable housing structure.

Preferably. the housing structure is adapted to be assembled on a concrete slab. In this case. the lower marginal edge of the external outer laminate of each wall panel preferably extends downwardly beyond the core laminate and the internal laminate to define a right angled rebate adapted to rest along a corresponding edge portion of the concrete 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 embodiment, a weatherproof flashing strip is positioned between the foundation slab and the overlying wall panels.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: 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 cement rendering, Figure 3 is a cutaway plan view showing a pair of panels according to Figures I and 2, interlocked and fastened together in tongue and groove relationship to form a composite panel assembly according to the invention; Figure 4 is a perspective view showing the reinforcing channel member or stud of the panels of Figures 1 and 2; WO 98/50646 PCT/AU98/00330 -8- Figure 5 is a perspective view showing a composite panel similar to that shown in Figure 1. adapted for use as part of an internal wall according to the invention; Figure 6 is a plan view showing the use of a stud positioned in reverse orientation to 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 beams in 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 concrete foundation slab according to the invention; Figure 12 is a front elevation showing the mounting detail of Figure 11; Figure 13 is a plan view showing a wall to wall corner detail according to the invention: Figure 14 is a cross sectional view showing a wall to roof fastening method according to the invention; and Figure 15 is a front elevation showing a housing structure fabricated from composite panels according to the invention.

PCT/AU98/00330 Received 15 February 1999 -9- [AMENDED PAGE] 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 sandwiched therebetween. The outer laminates and the core laminate are offset such that respective edge portions 5 and 6 of the outer laminates protrude beyond the core by a predetermined margin A along a first edge of the panel. Similarly, an edge portion 7 of the core laminate protrudes beyond the outer laminates by a generally corresponding margin 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 protruding core portion 7 of an adjacent like panel in interlocking relationship to form a composite 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 polystyrene foam, between 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 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 special purpose cross-linking polymer adhesive suitable to the purpose. This form of panel is particularly suitable for use as an external wall, with the plywood layer facing outwardly to receive a weatherproof finish.

A preferred form of external finish is shown in Figure 2, whereby a sheet of 7expanded steel mesh 10 is stapled to the plywood laminate and subsequently covered ith a layer of cement rendering 11. In this way, the steel mesh acts as reinforcement AMENDED SHEET

IFEA/AU

PCT/AU98/00330 Received 15 February 1999 [AMENDED PAGE] for the rendering. A final protective coat of weatherproof paint is then applied. The internal 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 covers the protruding portion of the core laminate 4, so as to form a stud. It should be appreciated, however, that an alternative configuration is possible wherein the U-shaped channel 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 apart flanges 16 and an intermediate web 17 with a longitudinally extending rebate 18 for 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 respective outer laminates 2 and 3 along the corresponding edge of the panel whilst the web 17 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.

In the alternative configuration, the U-shaped channel member 15 is positioned in the 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 the outer laminates 2, 3 and extend outwardly from the recess.

0 AMENDED SHEET

!PEAIAU

PCT/AU98/00330 Received 15 February 1999 [NEW PAGE] The channel members 15 are pressed from sheet metal 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 panels range from approximately 900 mm in width, 2500 4000 mm in height and 65 90 mm 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 cut down as required, for example to accommodate windows, doors, beams, roof panels, and other fittings, without loss of structural strength.

AMENDED SHEET

!PEAI.AU

WO 98/50646 PCT/AU98/00330 -Il- 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 internal walls, where weatherproofing is not required.

Figure 6 shows an alternative form of assembly whereby the protruding edges 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 viewing the drawing) to form a tongue in a manner similar to the protruding core portion on the opposite side of the panel. In this way. the left side panel engages the right side panel 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 panel, the channel flanges, and the channel web. This cavity may be used for concealed routing of building services such as electrical cables, water pipes, telecommunication lines, 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 and groove relationship by a series 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 the panels together. A line of screw fasteners thus extend along the adjoining edges of each adjacent pair of panels. The panels are further secured by a top capping strip 22 which WO 98/50646 PCT/AU98/00330 -12also 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 metal, the upper layer 2 being Scorrugated to provide increased strength, improved water run-off and a conventional aesthetically pleasing appearance. This arrangement is particularly well adapted for use as a roof panel 24 since, being essentially self-supporting, it obviates the need for a roof framing structure other than a central support beam as described below.

Figure 8 shows how the basic elements 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 4 formed from expanded polystyrene foam, preferably 50mm in thickness as per the panels described above. The same cross-linking polymer adhesive is used to adhere 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 channels also act as capping strips to seal and protect the relatively soft foam core laminate. It has been found that this beam provides adequate 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 of Figure 8 to a vertical wall panel. The saddle bracket is cut and folded from a WO 98/50646 PCT/AU98/00330 -13straight length of 90' angled sheet metal as shown, using a suitable template orjig. It is then hooked over the upper edge of the wall panel in the appropriate location, and secured into position with screw fasteners, some of which extend into the top metal capping strip 22, and some of which extend directly into the panel. ideally into a vertical stud to give direct metal-metal engagement between these primary structural elements.

This arrangement provides adequate support for the structural beam, without the need to cut slots, recesses or rebates into the wall panel itself. This substantially expedites the construction process without compromising structural integrity. A similar double-sided saddle bracket 27 may be used, if the structural beam is effectively to continue from the opposite side of the wall panel, as would often be the case with internal walls. This is best illustrated in Figure Figure 11 shows how in building and housing construction applications, the wall panels are fastened to a concrete foundation slab 30. The concrete slab is first poured to the appropriate dimensions using conventional 'ormwork techniques. The lower surface of each external wall panel is rebated, such that the lower marginal edge 3 1 of the external laminate 2 of each panel extends downwardly beyond the core laminate 4 and the internal laminate 3 by a margin C. The resultant 90' rebate allows the panel to rest along the outer edge of the foundation slab, with the lower edge 31 of the outer laminate providing positive and accurate lateral 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 in Figure 11 such that the flashing strip is tightly sandwiched between the rebates of the panels and the corresponding edge of the slab. At this stage, the wall panels are secured WO 98/50646 PCT/AU98/00330 -14in position by dyna-bolts 34 or similar fasteners, which extend through the lower edge 31 of the outer laminate, and directly into the slab through pre-drilled poles.

Where adjacent wall panels join, a metal 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 outer 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 a dyna-bolt 34 extends through the lower end 36 of the anchor strip, through the lower edges 31 of the outer laminates, and thence into the slab. The upper fasteners 21 extend through the upper end 37 of the anchor strip, through the outer laminates of the adjacent panels, through the underlying stud, and into the core. By this means, the entire panel assemblies, and not merely the outer laminates, are anchored directly to the foundation slab. Moreover, the studs are disposed to transfer load directly from the walls and the roof to the concrete 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 many structures built in accordance with conventional techniques.

Figure 13 shows an enlarged comer detail, illustrating how the wall panels 1 are abutted together at a 900 corner, and joined by means of an angled metal corner strip Each face of the comer 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 to a vertical wall panel 1, by means of respective internal and external angle brackets 43 WO 98/50646 PCT/AU98/00330 and 44. As shown in the drawing, screw fasteners are used to secure the lower face of each bracket 43 and 44 to the top capping strip and elsewhere on the wall panel whilst the 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 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 present invention, the concrete foundation slab 30 is first layed using conventional form work techniques. The flashing strip 32 is then positioned around the periphery of the foundation slab. The external wall panels 1 are then positioned such that the outer edge of the concrete slab nests in the rebate with the lower edge 31 of each panel extending downwardly over the outer edge of the slab. The wall panels are then secured to the slab with dyna-bolts 34 or similar fastening elements, 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 in Figure 13. The upper edges of the wall panels are then covered and sealed by the Ushaped capping strips 40. as shown in Figures 9 and 11, which adds further structural integrity to the panel assembly. Window and door frames are cut from the wall panels as required, and finished with framing elements formed from timber or aluminium extrusions, as required. At this stage, the external wall structure is complete, save for finishing which will be described below.

WO 98/50646 PCT/AU98/00330 -16- 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. Roof panels 24 of the type shown in Figure 6 are then added, as shown in Figure 14. The roof structure is finished with a capping strip 50 and guttering 51. as shown in Figure Internal walls are then formed as required, using interior wall panels of the type shown in Figure 5. Again, spaces for internal windows and doors are cut from the panels and framed as required. The internal joints between the plaster board sheets associated with the discrete panels are concealed and finished using conventional plastering techniques, and finally painted. Skirting and cornices may also be added as required to conceal floor-wall and wall-roof joints, for added weather protection, and to provide a conventional aesthetic appearance.

The exterior panels may be weatherproofed and finished as desired. A particularly preferred form of finishing, however, involves the step initially of stapling expanded steel mesh sheeting 10 to the exterior plywood laminate 2, and subsequently applying a layer of cement render 11, within which the expanded steel mesh acts as reinforcement.

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

Advantageously. a house, factory or other building manufactured in accordance with the present 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 tfoundations and structural framing are required, which further reduces material and labour costs. Because the entire set of panels may be pre-fabricated off site, the building can be erected with minimal use of WO 98/50646 PCT/AU98/00330 -17skilled labour, further reducing costs. Because of the laminate construction of the panels. and in particular the substantial polystyrene foam core, the building inherently possesses thermal and acoustic insulation properties far superior to those exhibited by conventional buildings, again without the use additional resources such as fibreglass batts or the like. Because of the unique way in which the panels are anchored to the concrete foundation slab, the structure is particularly resistant to wind loadings, even under cyclonic conditions. A further advantage offered by structures built in accordance with the present invention is that of flexibility in design. Even after the structure has been completed, internal as well as external walls may be added, removed or changed as 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 to another site and subsequently rebuilt with considerable ease. Even in the event that a dwelling is to be entirely demolished, the individual panels and other components may simply 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 present system provide their own inherent structural integrity and thus the system as a whole avoids the need altogether for a separate frame work. It will thus be appreciated that the invention provides practical and commercially significant improvements over the prior art.

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

Claims (45)

1. [AMENDED] 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 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 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, said composite 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. [AMENDED] A composite panel according to claim 1, wherein said channel member covers the protruding portion of the core laminate so as to form a stud.

3. [AMENDED] 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 flanges .lie parallel to and immediately inside the respective outer laminates along the corresponding edge of the panel and such that the web extends between the flanges to cap the protruding portion of the core laminate.

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 outer laminates whereby the channel member is adapted to be pressed into position and is substantially self-locating.

AMENUD SHEE /PEA/AU PCT/AU98/00330 Received 15 February 1999 -19- [AMENDED PAGE] [AMENDED] A composite panel according to any one of claims 1 to 4, wherein the channel member is pressed from sheet metal and is oriented in use to form a generally vertically extending stud between adjacent panels, thereby providing additional structural integrity for the composite panel assembly when used to form a composite wall.

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 portions of 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 reverse orientation protrudes beyond the outer laminates to define 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.

8. A composite panel according to any one of the preceding claims, wherein the core laminate is formed from expanded polystyrene 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 situ.

AMENDED SHEET i P Ai.AU PCT/AU98/00330 Received 15 February 1999 [AMENDED PAGE] A composite panel according to claim 9, further including a layer of expanded steel mesh applied to the outer plywood laminate, and a layer of cement render applied to the steel mesh, such that the steel mesh acts as reinforcement for the cement render.

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

12. A composite panel according to claim 11, wherein the internal. layer of plasterboard is filled and finished to conceal join lines.

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

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

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

16. [AMENDED] A composite panel according to any one of the preceding claims, wherein adjoining panels of a panel assembly are secured in overlapping tongue and groove relationship by at least one fastener, said fastener extending through an outer laminate of one panel, through a flange of the channel member and into the core laminate of the adjacent panel, thereby securing the adjoining panels together. [ORIGINAL CLAIM 17 DELETED] 0 PAMENED SHEET !PFAIAU PCT/AU98/00330 Received 15 February 1999 -21- [AMENDED PAGE]

17. [ORIGINAL CLAIM 18 RENUMBERED AND AMENDED] 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. [ORIGINAL CLAIM 19 RENUMBERED] A composite panel according to any one of the preceding claims, wherein the core laminate is between 20 mm and around 100 mm in thickness.

19. [ORIGINAL

CLAIM 20 RENUMBERED] A composite panel according to claim 18, wherein the core laminate is formed from expanded polystyrene foam and is between 50 mm and around 60 mm in thickness. to 20. [ORIGINAL CLAIM 21 RENUMBERED] 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. [ORIGINAL CLAIM 22 RENUMBERED] A composite panel according to claim 1, comprising a foam core laminate sandwiched between outer layers of sheet metal.

22. [ORIGINAL CLAIM 23 RENUMBERED] A composite panel according to claim 21, being adapted for use as a roof panel.

23. [ORIGINAL CLAIM 24 RENUMBERED] A composite panel according to claim 22, wherein the internal outer laminate is formed from substantially flat sheet metal and wherein the external outer laminate is formed from corrugated sheet metal to provide increased strength, improved water run off, and a conventional corrugated iron appearance. )AMENDED SHEET !PEAI1AU PCT/AU98/00330 Received 15 February 1999 -22- [AMENDED PAGE]

24. [ORIGINAL

CLAIM 25 RENUMBERED] 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. [ORIGINAL CLAIM 26 RENUMBERED] A building structure comprising internal and external walls, each being formed as an interlocking composite panel assembly substantially as defined in any one of claims 1 to 24.

26. [ORIGINAL CLAIM 27 RENUMBERED AND AMENDED] 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. [ORIGINAL CLAIM 28 RENUMBERED] A building structure according to claim 26, wherein the structural beam is formed from a core laminate formed from expanded polystyrene foam, outer laminates formed from plywood, and capping strips formed from generally U-shaped channel members to cover the exposed longitudinal edge portions of the core laminate.

28. [ORIGINAL CLAIM 29 RENUMBERED] A 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 being cut and folded from an initially straight strip of angled sheet metal, thereby obviating the need for slots, recesses or rebates in the wall panel.

29. [ORIGINAL

CLAIM 30 RENUMBERED] A building structure according to any one of claims 25 to 28, wherein generally U-shaped capping strips are positioned )iAMENDiED SHEET !PEA/AU PCT/AU98/00330 Received 15 February 1999 -23- [AMENDED PAGE] along the upper marginal edges of the wall panels to provide additional structural strength for the walls and to facilitate fastening of the roof panels thereto. [ORIGINAL CLAIM 31 RENUMBERED] A building structure according to any one of claims 25 to 29, wherein the structure is adapted for assembly on a concrete foundation slab.

31. [ORIGINAL CLAIM 32 RENUMBERED] A building structure according to claim 30, wherein the lower marginal edge of the external outer laminate of each wall panel extends downwardly beyond the core laminate and the internal laminate to define a substantially right angled rebate adapted to rest along a corresponding edge portion of the concrete foundation slab.

32. [ORIGINAL CLAIM 33 RENUMBERED] A building structure according to claim 31, further including fastening elements extending through the external outer laminate and into the foundation slab to prevent the structure from lifting in adverse weather conditions.

33. [ORIGINAL CLAIM 34 RENUMBERED] A building structure according to claim 32, wherein the wall panels are fastened to the foundation slab by means of"dyna- bolts".

34. [ORIGINAL

CLAIM 35 RENUMBERED] A building structure according to any one of the claims 30 to 33, further including a weatherproof flashing strip positioned between the foundation slab and the overlying wall panels. [ORIGINAL CLAIM 36 RENUMBERED AND AMENDED] A method of forming a composite panel, said method comprising the steps of sandwiching a core laminate between spaced apart outer laminates such that portions of the outer laminates AMENIDED SHEET IPEAIAU PCT/AU98/00330 Received 15 February 1999 -24- [AMENDED PAGE] protrude beyond the core by a predetermined 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, providing a generally U- shaped channel member which forms a stud for interlocking engagement with a complementary edge of 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.

36. [ORIGINAL CLAIM 37 RENUMBERED] A method of forming a building structure, comprising the steps of forming external walls, forming internal walls, and forming a roof, each from a series of interlocking composite panels, each panel being formed substantially in accordance with the method of claim 35, and comprising the further step of fastening the respective panels together to form a stable housing structure.

37. [ORIGINAL CLAIM 38 RENUMBERED] A method according to claim 36, comprising the further step of assembling the housing structure on a concrete foundation slab.

38. [ORIGINAL CLAIM 39 RENUMBERED] A method according to claim 37, comprising the further step of forming the lower marginal edge of the external outer laminate of each wall panel so as to extend downwardly beyond the core laminate and the internal laminate, and thereby defining a substantially right angled rebate adapted to rest along a corresponding edge portion of the concrete foundation slab.

39. [ORIGINAL

CLAIM 40 RENUMBERED] A method according to claim 38, 0 comprising the further step of installing fastening elements so as to extend through the 0 AMENDED SHEET IPEA/AU outer laminate and into a side of the foundation slab, thereby to prevent the housing structure from lifing in adverse weather conditions. A method according to claim 39, wherein said fastening elements are "dyna-bolts".

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

42. A composite panel substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings.

43. A building structure substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings.

44. A method of forming a composite panel substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings.

45. A method of forming a building structure substantially as herein described with reference to any one of the embodiments of the invention illustrated in the 15 accompanying drawings. o.oo. DATED this 29th Day of March, 2000 *NABIL NASRI GAZAL Attorney: STUART M. SMITH Fellow Institute of Patent Attorneys of Australia 20 of BALDWIN SHELSTON WATERS 957AUPOO.DOC