AU2008247332A1 - Building module, connection means and method for forming spatial structures - Google Patents

Description

WO 2008/134824 PCT/AU2008/000641 BUILDING MODULE, CONNECTION MEANS AND METHOD FOR FORMING SPATIAL STRUCTURES 5 FIELD This invention relates to building modules, made from cardboard or other semi rigid flat sheet materials, which may be used to form whole or partial spatial structures for use as shelters, dwellings, playhouses, pet shelters, fantasy, or education and for other purposes. 10 BACKGROUND Structures formed from cardboard materials, such as corrugated cardboard of the type used in packaging, have been proposed in the past but are usually formed from components such as columns and beams which replicate typical wooden structures. See for 15 example: "newhousingofthefuture.com.au/downloadables/hof-fact-sheets.cardboard.pdf'. In order to fully benefit from the use of cardboard or other semi-rigid lightweight materials, a structure formed from modular components not requiring a separate supporting framework has been determined as most suitable for erection using no tools and limited skill or instruction. 20 In the past, prefabricated structures used in shelter provisioning often arrive on location well after the emergency has passed due to the distance between the factory supplying the structures and where they are needed. In order to benefit from more self reliant shelter provisioning, a construction system constituting structural elements able to be made utilising existing manufacturing infrastructure already available in many countries 25 has been determined as most suitable for emergency contingencies and development programs. Fasteners often constitute a significant portion of overall structure costs. In order to benefit from user-friendly fasteners, less expensive fasteners, able to be made from waste material and pre-fabricated by end-users, has been determined as most suitable for more 30 affordable shelter provisioning.

WO 2008/134824 PCT/AU2008/000641 -2 SUMMARY OF THE INVENTION In one form, the invention provides a building module made from folded semi-rigid flat sheet-like material, such as cardboard, and having a flat polygonal base panel having at least three sides, one or more sides provided with a side panel, or sidewall, said sidewalls 5 are folded and held at a desired angle to the base panel to define an open or closed shallow box-like building module, said module being adapted to be used with similar modules secured to each other by a connecting means and a fastening means, formed from similar sheet-like material, with the sidewalls engaged to form a spatial structure or part of a structure. 10 The outside dimensions of each base panel are the same as the individual polygons constituting a theoretical polyhedral surface on the desired structure's external surface, conveniently subdivided to suit the invention. Building module sidewalls are connected together at each corner of the module to hold the sidewalls at their required angles, and this can be achieved by taping the sidewalls 15 together. However, it is preferred that the sidewalls are held together at each corner by corner holding mechanisms formed as foldable flaps at the corners of the module to securely lock the sidewalls together and to strengthen the module. The ends of the sidewalls are angularly formed such that when adjacent sidewall panels of the same module are folded together, the sidewalls at the base panel of the module are sloped 20 inwardly (re-entrant), or outwardly (salient), and, the closed sidewall panels at the corners of the module are sloped inwardly, or outwardly, to enable a plurality of similar modules to form the desired form of spatial structure with all connecting sidewalls fully engaged and connected to each other, and with all module corner sides at the structure's vertices substantially closed on the structure's interior and exterior surfaces. 25 In one form, the module sidewall ends are cut to a predetermined length and at a predetermined angle, which determines the angles at which the sidewalls to the base and module corner edges to the base will be disposed when the module is formed from the blank. The predetermined length of the sidewall angularly formed end edges determines the depth of the module. 30 One or more sidewalls may also be formed with a central flap, which is foldable to partially or fully close the inside, or outside, face of the module to form a closed rigid box- WO 2008/134824 PCT/AU2008/000641 -3 like structure. The connection means are provided by a plurality of fasteners and pairs of cooperating tabs. Fasteners are most suitably formed from the same sheeting material as modules and are shaped to engage aligned slots in module sidewalls to join connecting 5 modules to form a spatial structure with its external surface substantially closed by connected sidewalls. However, depending on application permanency, the sidewalls may be connected adhesively, such as by glue applied to the outside surfaces of the sidewalls between modules, or by adhesive tape connecting base exterior faces or by other means to close the spatial structure's external surface more permanently. 10 In one form, the fasteners comprise a narrow strip of sheeting material folded multiple times and formed with a slot in one edge, which is dimensioned to engage the sidewalls of connecting modules via the slots in the sidewalls, to securely hold them together and form a substantially stable structure. Additionally or alternatively, each sidewall may be provided with one or more 15 spaced male edge tabs and one or more spaced female apertured hinging edge tabs which can be inter-engaged to locate and connect opposing sides of connecting modules together to substantially close the internal surface of the spatial structure by connected sidewalls. In one form, an apertured hinging tab is folded over to engage a rigid alignment tab extending from the sidewall. To enable the connection of opposed sides, the hinged tabs 20 and alignment tabs are sequentially located around the periphery of the modules so that when aligned, tabs of connecting modules oppose each other as cooperating pairs. The fastener is most suitably formed from the same material as the building module and in one form comprises a narrow strip folded multiple times and formed with a slot in one edge which is dimensioned to engage the sidewalls of connecting modules via slots in 25 the sidewalls, to securely hold them together. In its simplest form, the polygonal base panel is shaped as a triangle, and a thus shaped module may be used to form various spatial structures, such as, but not limited to, geodesic domes from a one or two frequency dome, suitable for play or learning purposes, to a three or high frequency dome, suitable for use as a temporary shelter or housing 30 structure or for training and education purposes.

WO 2008/134824 PCT/AU2008/000641 -4 Other polygonal shaped base panels may be used, including square, pentagonal, hexagonal, octagonal etc and may be adapted to form various spatial structures. Rectangular polygonal base panels may be used to form vault-like structures. Base panels of any polygonal shape may be adapted to form any structure that can have its surface 5 subdivided as a polyhedral surface. Suitably constructed passageways to provide rooms and service facilities for a larger housing structure may conjoin several spatial structures. Base panels provided with a single sidewall and connection means may be used as hinged structural elements to align passageways conjoining structures. 10 The invention also provides a construction system comprising a multiplicity of blanks of flat sheet-like material, such as cardboard, foldable to form a multiplicity of similar building modules of shallow box-like form having sidewalls, paired connecting means, and fastener means of folded flat sheet-like material which align and engage and cooperate with slots in the sidewalls of building modules to connect the sidewalls together 15 to form spatial structures. In one form of the above aspect of the invention, the building modules and connection means may be as defined above. The invention further provides a method of forming a structure comprising the steps of die-cutting a multiplicity of blanks of flat sheet-like material, such as cardboard, 20 folding the blanks to form shallow box-like building modules having sidewalls, and joining opposing sidewalls using folded fasteners of similar sheet-like material to form a spatial structure. In one form the method is performed using building modules and connection means as defined above. 25 BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is an elevation of a building module from which spatial structures of 30 various configurations can be formed; Figure 2 illustrates a die cut blank, or unfolded cut-out from which the building WO 2008/134824 PCT/AU2008/000641 -5 module of Figure 1 is formed; Figure 3 is a detailed view of the corner holding mechanism; Figure 4 is an enlarged view of one lid flap; Figure 5 illustrates distortion control and dimension stability features of the 5 building module; Figures 6 and 7 illustrate the extra closure feature on the lid; Figures 8 to 10 illustrate the fasteners and how they are used; Figure 11 illustrates foldable block cut outs and folded block examples for supporting the bottom of a structure formed from the building module; 10 Figures 12 illustrate prefabricated grouped modules; Figure 13 illustrates assembled structure forms; Figures 14 to 17 illustrate simplified forms of the modules of Figures 1 and 2; Figures 18 to 20 shows building modules of vault architectural form to illustrate other polygonal shaped bases adaptable; and 15 Figures 21 to 24 illustrate how sidewall end angularity is derived. DESCRIPTION OF EMBODIMENT In the first embodiment illustrated in the drawings, Figure 1 shows a triangular hollow box-like building module embodying the invention. The corrugated cardboard 20 blank from which the module is formed is shown in Figure 2, and comprises a triangular planar element or base panel 1 defined by score or fold lines and having foldable sidewalls 2 extending from each side, formed with fastener slots 3 and sidewall angular end edges A and B shown in Figure 3 cut to the predetermined length according to the desired module depth. Aspects of geometry are described at the end of this section. 25 As adjacent sidewalls are folded together they are rotated until end edges A and B are positioned flushly together to form the required module side slope and the required module corner slope, which enable spatial structures to be formed with significant precision with all module sides fully engaging and connected to each other and with all the structure's module vertices substantially closed. 30 Each sidewall 2 carries a rigid male alignment tab 4 and a slotted hinged female alignment tab 5 which cooperate with like tabs and slots on like modules to locate, align WO 2008/134824 PCT/AU2008/000641 -6 and hold the modules together with sidewalls engaging, to close the interior surface of the spatial structure, and held by fasteners engaging aligned fastener slots 3, to close the exterior surface of the spatial structure, and to form spatial structures as described further below. 5 The sidewalls also carry corner holding flaps 6 and 7 at either end, which when folded along the fold lines 64, 65, 74 and 75, lock the sidewalls 2 together at the corners of the module. A central lid compartment, lid 8, extends from each sidewall and is shaped when folded along the illustrated fold lines to close the module as illustrated in Figure 1. As shown most clearly in Figure 3, the male and female corner holding flaps 6 10 and 7 are generally triangular to fill and substantially hold the corners between adjacent sidewalls 2 in precise position when the angular ends A, B are positioned together fully along their lengths. The female flap 7 has an edge flap 70 which is folded along fold line 71 and has an extended portion 72 which engages the base panel 1 when the flap is folded to support the 15 flap 7 at the required level to close the corner. The flap 70 is cut away at 73 to enable the adjacent fastener slot to be accessed. The male corner holding flap 6 includes a flap portion 60 which is foldable along a fold line 61 set in from the edge and having a locking tab 62 extending from one end, and which is foldable along fold line 63. Flap 60 is folded inwardly and perpendicular to flap 6 20 and the locking tab 62 is folded outwardly to the outside face of portion 60 before flap 6 is folded over flap 7. This allows the flap 60 to engage the slot in the base of flap 7 created by the formation of male locating tab 4. When the folded flap 60 passes through the slot, the flap is bent towards the bottom of flap 7 until the folded locking tab 62 is opened and flaps 60 and 62 spring back together to lock the corner holding flaps 6 and 7 in their closed 25 positions. In this state the flaps 6 and 7 brace and strengthen the corner they are located near and hold the ends of the sidewalls 2 defining the corner together to ensure, when all other corners are similarly held and locked, the sidewalls are maintained at the required angles to the base panel 1. Before corners are locked in place, check tab 6a is located in cutaway 7a to confirm 30 the correct positioning of the corner flaps.

WO 2008/134824 PCT/AU2008/000641 -7 Sheeting material has a certain thickness. Since measurements are taken as line to line outside dimensions, bevelling crush lines a, b located near sidewall angular end edges A, B may be provided on blanks to allow for sheeting material thickness so that outside and inside edges of module corners are able to be fully closed. Alternatively, the bevel 5 crush can be achieved by running a thumbnail along the edge by hand or by using a rudimentary hand tool that can replicate the same action. Crush bevels a, b enable the precision available on cut out blanks to be transferred more efficiently during module fabrication, and thus facilitate exact module to module fit and a consistency of dimension in final structures achievable by novice users. 10 As shown most clearly in Figure 4, the compartment lid flaps 8 are connected to sidewalls on fold-line 87. The lid flaps 8 have edge portions 80, 81 joined by a central apertured link 82 and each edge portion has folding flaps 83, 84 extending from its free edge. The folding flaps 83, 84 are folded inwardly on fold lines 85, 86 of edge portions 80, 81 and edge portions are folded inwardly whereby the folding flaps engage the base to 15 support the lid flaps 8 at the required level above the base and position edge portions to engage opposing lids so formed. Link 82 connects, stabilises and aligns portions 80 to 81. When folded, linked edge portions resist inward movement, independently or together, past their designed position, enabling lid flaps to be frictionally closed against opposing edge portions. Closed lids enhance module structural integrity and performance under 20 structural loads. Without link 82, lids may not close in the intended manner or may open unexpectedly. End edges 80a, 81 a of portions 80, 81 are fashioned shorter in length than opposite end edges 80b, 81b to cause portions 80, 81 to taper or ramp towards lid convergence centre 90, shown in Figures 5 to 7. The ramped portions create a lid twist and a depression 25 or dish effect on lid side of the module when all lids are closed. The general direction of the depression is illustrated in Figure 7. The lid twist and dish effect transfers a useful force and support for the otherwise unsupported module base via portions 80, 81. Untreated corrugated cardboard is hydroscopic and affected by cyclic humidity. Such effects can be manifested in various forms of warping of unsupported spans of the sheet 30 material. Modules made with untreated cardboard, and exposed to cyclic humidity, may experience a warp that tends to bow bases inwardly and could push lids open from the WO 2008/134824 PCT/AU2008/000641 -8 inside. Lid twist and dish effects inhibit base bow, which would otherwise force lids open, thus preserving module structural integrity and prolonging its useful life. Lid edges nearest corners may be positioned below closed corner flaps 6 and 7 such that the free edge of lid 8 is frictionally locked under the corner flaps to create the 5 additional lid closure feature, illustrated in Figures 5 and 6. Lengths of end edges 80b, 81b of portions 80, 81 are fashioned such that the free edges of lid flaps 8 ramps toward position 89, to close below the level of flaps 6 and 7 of formed corners. Flaps 6 and 7 frictionally inhibit the free edge of lid 8 moving thus contributing to overall lid closure. When lids are not closed, modules are in a more relaxed state and the sheeting 10 material used to make modules is freer to distort in an uncontrolled manner over time if affected by warping or other material distorting effects. If affected by conditions causing the material to warp or distort, modules with effective lid closure retain their design features longer for a given stress condition, thereby minimising negative material distortion effects and contributes to module performance, providing stronger structures and 15 prolonging their useful life. In this first embodiment, closed lids provide a building module with three additional compartmental support sections and formed corners provide three structurally braced areas, the engineering of which originates from a single cut out blank. The aggregate of compartments and corners, some of which can be appreciated on grouped 20 module example illustrations shown in Figure 12, provide significantly enhanced structural benefits to the frameless modular structures made without power tools and from a lightweight material such that no glueing is required if a structurally sound temporary configuration is required. Referring to Figures 8 to 10, fasteners suitable to connect modules are illustrated. 25 Each fastener 10 is a multiple-folded rectangular strip 101 of cardboard, which may be cut from the waste board remaining after the blanks of Figure 2 are die-cut. The strip 101 has outer fold lines 102 and a central double fold 103 to allow the outer folded portions to be accommodated between the inner portions folded at the central fold 103 to form a four thickness fastener 10. Each of the folded portions has a central slot 104 dimensioned to 30 engage two thicknesses of sidewall board and the width of the strip allows the fasteners 10 to engage the slots 3 for sliding movement to engage the slots 104 with the sidewall board WO 2008/134824 PCT/AU2008/000641 -9 at the ends of the slots 3. Figure 9 shows fastener fabrication. Figure 10 shows fastener operation to connect two module sidewalls. In the first embodiment three slots 3 are formed in each sidewall and this is sufficient to securely fasten the sidewalls of connecting modules. In other embodiments, one, two or more fastener slots may be provided for. 5 Two or more modules can be assembled by the use of such fasteners 10, together with cooperating tabs 4, 5, to form grouped modules, as examples in Figure 12, building sections, as in example in Figure 20; or structures, as in Figure 13, having sufficient properties to serve as a temporary shelter, or as a more or less permanent structure, dependent on application requirement, including uses for play or education resources. 10 Since sidewalls are usually slightly different in length but visually similar, it is easy to confuse sidewall orientation when connecting modules. Reference shaped or coloured dots may be provided on modules for explanation, orientation and/or instructional purposes. Red circular dot 6b shown in Figure 3 is used to indicate which corner of the connecting module is oriented at the vertex of a hexagonal or half-hexagonal panel. 15 Another shape and/or colour may indicate similar information for another particular panel e.g. for a pentagonal type panel. Since the bottom of some of the structures formed from the modules embodying the invention are not flat, the bottom may need to be supported to prevent distortion of the structure. Suitable supports blocks formed from cardboard waste material are illustrated in 20 Figure 11 but may take other forms. Also shown are: block cut out blank; partially folded cut out; and a support block formed with bamboo skewer rods for non-glue applications. The predetermined sidewall end edge angularity is derived from the angle between the base panel edge and a theoretical projection from either end points of base panel edge to a centre of structure reference point, or to a central reference axis, or to a relevant 25 reference dimensional plane, or to a combination of centres, axes and/or planes, or to similar end points of a base panel edge from polygons of a theoretical smaller duplicate polyhedral surface within the structure. In the first embodiment Figures 21, 22 shows P as the a centre of structure reference point; curved arrows point to the sidewall angularity to be determined; A, B are sidewall angular ends; M, N are base 1 of connecting modules; SS 30 are sidewalls together; R, Q are theoretical projections to centre of structure. As examples of other embodiments, Figures 23, 24 shows K as central reference axis for a vault or WO 2008/134824 PCT/AU2008/000641 - 10 barrel vault; L as relevant reference dimensional plane, offset at 90 degrees, for a cube structure. SIMPLIFIED AND OTHER EMBODIMENTS 5 Figures 14 and 15 illustrate a simplified form of the module in which the lid panels have been removed. While this form has less strength and rigidity than the previous embodiment, it is nevertheless able to function to form adequate spatial structures of different forms. 10 A fully simplified version without corner holding flaps is shown in Figures 16 and 17. This form requires the use of adhesive tape or the like to hold the corners and is therefore not particularly preferred. Nevertheless the module is able to function to form spatial structures useful for limited purposes. Figures 18 to 20 show an example of building modules, which are capable of 15 forming spatial structures such as vaults. The example incorporates the fastening and alignment features of the first embodiment as well as some of the corner locking, lid closure, lid dish effect and features described above. In this other embodiment, the sidewalls effectively provide a spatial frame so that frameless structures can be formed without the use of struts or other frame members. An example of a cut out blank for a vault 20 module is illustrated in Figure 19. A section example of a spatial structure, which can be formed with building modules, is illustrated in Figure 21. Building modules may be formed as re-entrant, as in the first embodiment, or salient in nature. Salient embodiments are useful in applications where fastener accessed from the outside of a structure is required. 25 Modules may be modified so that some features are removed to enable the base panel to be inter-engaged in a structure as a hinging element. Suitably adapted doors and windows or attachments may be incorporated into structures in voids created by removing one or more modules and/or by modifying one or more module. 30 Where weather or water resistance is required, a fabric-like or tent-like material can be adapted over and under the structure to provide protection from water ingress.

WO 2008/134824 PCT/AU2008/000641 - 11 If a more substantial but still temporary structure is required, sidewalls may be connected adhesively, such as by tape applied to the faces or at the join between connecting modules to affix the spatial structure's external surface. This embodiment transforms the structures external surface into a membrane system imparting significant 5 structural strength advantages over un-taped modular structures. If the structure requires disassembling, tape joins can be slit with a knife prior to disassembly. If a more substantial and more permanent structure is required, corner flaps 6, 7 can be adhesively connected, also opposing sidewall faces can be adhesively connected; also, folding flaps 83 and 84 can be adhesively connected to base 1, as can lid edge portions 80 10 and 81 to opposing portions, such as with glue. While glued components deliver much improved structural strength advantages to the effects and features mentioned in the first embodiment it also renders structures difficult to disassemble to an original flat state. If a structure is required to withstand high wind forces, the structure can be securely fixed to an anchored base and/or harnesses, which can be fixed to the base or to 15 the ground, and adapted onto, over and around the structure. If a more substantial and durable structure is required, a suitable render or cladding material can be used to cover the exposed surfaces such as the interior or exterior surfaces of the assembled structure. Modules, fasteners and support blocks may be made from other semi rigid flat 20 sheeting including material of other thicknesses or from special materials with functional coatings and surface treatments, such as improvements to insulation or water resistance. Other multiple thickness fasteners such as a six-thickness fastener, shown in Figure 11, may be used in other embodiments. It will be appreciated from the above description of the various embodiments of the 25 invention that the described structural elements, (modules, fasteners and components), offer the following principal advantages: 1. The modules, fasteners and components can be formed from the same semi rigid flat sheeting material, such as corrugated cardboard, which is cheap, lightweight material, which is widely available in most countries, often made 30 from recycled material, and has properties which are well known and understood.

WO 2008/134824 PCT/AU2008/000641 -12 2. Structures formed from the modules, fasteners and components are frameless due to the strengths provided by the secured sidewalls and the described fastening mechanisms, and provided by the formations of edges and corners of modules and structural support provided by compartments. 5 3. The structures, modules, fasteners and components are able to be assembled by non-skilled persons with minimal instructions, without the use of power tools. 4. The structures, modules, fasteners and components are able to be disassembled and unfolded to their flat state for later use or recycling. 5. Structures formed from the building modules are able to be used as formwork 10 for a more substantial structure by the application of cladding and other building materials to the structures. 6. A plurality of the modules, fasteners and components constitute a construction system able to form spatial structures. 7. The modules, fasteners and components can be adapted to form any practical 15 structure, that can have their external surface suitably subdivided as a polyhedral surface, including single curved, double curved and 2-dimensional structural forms (such as flat walls). 8. The modules with lid features described herein are able to form stronger and more stable structures. 20 9. Structures formed using the modules, fasteners and components may be adapted for indoor or outdoor purposes. 10. The invention can be considered as monolithic in nature; as such, blanks can be prefabricated at the same time and place as fasteners and components. 11. Basic module features are derived from the one integral cut-out requiring no 25 additional engineered attachments, and fastener and support block blanks can be cut out from remaining waste sheeting material at the same time and place the module blank is made. Other advantages: 12. Structures formed from the modules, fasteners and components can be 30 temporary and reusable, more permanent but still re-usable, or more permanent and less re-usable.

WO 2008/134824 PCT/AU2008/000641 - 13 13. Formed modules and panels are stable and light enough to be carried around building sites. 14. In one form, where the modules, fasteners and components are being used as transitional housing formwork, the structure can be used as temporary shelter. 5 15. The construction system containing the modules, fasteners and components can be used in an emergency as emergency shelter and after an emergency as transitional housing formwork upgradeable to more permanent shelter, saving time, money, improving and saving lives and reducing pain and suffering. 16. Structures formed of closed building modules, being hollow and box-like, 10 provide a double skin effect to structures, affording acoustic and thermal insulation advantages over single skin or tent-like structures, advantageous where winterized shelter is needed quickly, or extra privacy is important. The invention has been described by way of non-limiting example only and many modifications and variations may be made thereto without departing from the spirit and 15 scope of the invention.

Claims (20)

1. A building module made from folded blank of semi-rigid flat sheet-like material, such as cardboard, and having a flat polygonal base panel having at least three sides, one 5 or more sides provided with a side panel, or sidewall, said sidewalls are folded and held at a desired angle to the base panel to define an open or closed shallow box-like building module, said module being adapted to be used with similar modules secured to each other by connecting fastening means formed from similar sheet-like material with the sidewalls engaged to form a spatial structure or part of a structure. 10

2. The building module of claim 1, wherein the outside dimensions of each base panel are the same as the individual polygons constituting a polyhedral surface on the structure's external surface.

3. The building module of claim 1 or 2, wherein the sidewall panels are connected together at each corner of the module to hold the sidewalls at predetermined angles. 15

4. The building module of any preceding claim, wherein the sidewalls are held together at each corner by corner holding mechanisms formed as foldable flaps at the corners of the module to securely lock the sidewalls together and to strengthen the module.

5. The building module of any preceding claim, wherein the ends of the sidewalls are angularly formed such that when adjacent sidewall panels are folded together the sidewalls 20 at the base panel of the module are sloped inwardly (re-entrant), or outwardly (salient), and, the closed sidewall panels at the corners of the module are sloped inwardly, or outwardly, to enable a plurality of similar modules to form the desired form of spatial structure with all connecting sidewalls fully engaged and connected to each other, and with all module corner sides at the structure's vertices substantially closed on the structure's 25 interior and exterior surfaces.

6. The building module of claim 5, wherein the sidewall ends are cut to a predetermined length and at a predetermined angle, which determines the angle at which the sidewalls and corner edges will be disposed when the module is formed from the blank. WO 2008/134824 PCT/AU2008/000641 - 15

7. The building module of claim 6, when the predetermined sidewall end edge angularity is derived from the angle between the base panel edge and a theoretical projection from either end points of base panel edge to a centre of structure reference point, or to a central reference axis, or to a relevant reference dimensional plane, or to a 5 combination of centres, axes and/or planes, or to similar end points of a base panel edge from polygons of a theoretical smaller duplicate polyhedral surface within the structure.

8. The building module of any preceding claim, wherein each side panel is formed with a central flap, which is foldable to partially or fully close the inside, or outside, face of the module to form a closed rigid structure. 10

9. The building module of claim 8, wherein each flap is configured so that the closed face of the module is inwardly dished to provide effective flap closure to inhibit distortion and to retain dimensional stability of the module.

10. The building module of any preceding claim, wherein the connecting fastening means include a plurality of fasteners and pairs of cooperating tabs. 15

11. The building module of claim 10, wherein the connecting fastening means further includes fasteners formed from cardboard and shaped to engage aligned slots in the sidewalls of modules to join connecting modules to form a spatial structure with its external surface substantially closed by connected sidewalls.

12. The building module of claim 11, wherein each fastener comprises a narrow strip 20 of cardboard folded multiple times and formed with a slot in one edge, which is dimensioned to engage the sidewalls of connecting modules via the slots in the sidewalls, to securely hold them together and form a substantially stable structure.

13. The building module of any preceding claim, wherein each sidewall is provided with one or more spaced male edge tabs and one or more spaced female apertured hinging 25 edge tabs which can be inter-engaged to locate and connect opposing sides of connecting modules together to substantially close the internal surface of the spatial structure by connected sidewalls. WO 2008/134824 PCT/AU2008/000641 -16

14. The building module of claim 13, wherein the apertured hinging tab is folded over to engage a rigid alignment tab extending from the sidewall, to enable the connection of opposed sidewalls, the hinged tabs and alignment tabs are sequentially located around the periphery of the modules so that when aligned, tabs of connecting modules oppose each 5 other as cooperating pairs.

15. The building module of any preceding claim, wherein the polygonal base panel is shaped as a triangle, and a thus shaped module may be used to form various spatial structures, such as, but not limited to, geodesic domes from a one or two frequency dome suitable for use as a small playhouse, to a three or more frequency dome, suitable for use 10 as a temporary shelter or housing structure.

16. A spatial structure comprising a multiplicity of building modules as defined in any one of the preceding claims connected by fastening means within the sidewalls of adjacent modules engaging each other to form the spatial structure or part thereof.

17. A construction system comprising a multiplicity of blanks of flat sheet-like 15 material, such as cardboard, foldable to form a multiplicity of similar building modules of shallow box-like form having sidewalls, connecting fastening means of similar sheet-like material which cooperate with the sidewalls of the building modules to connect the sidewalls together to form a spatial structure.

18. The construction system of claim 17, wherein the building modules and connecting 20 fastening means are as claimed in any one of claims 1 to 15.

19. A method of forming a structure comprising the steps of die-cutting a multiplicity of blanks of flat sheet-like material, such as cardboard, folding the blanks to form shallow box-like building modules having sidewalls, and joining opposing sidewalls using connecting fastening means of similar sheet-like material to form a spatial structure. 25

20. The method of claim 19, wherein the building modules and connection means are as claimed in any of claims 1 to 15.