GB2079808A - Improvements in or relating to building structures - Google Patents

Abstract

A building structure that is readily erectable (e.g. in an emergency to provide housing, offices, or other accommodation) from a plurality of like modular units, each unit being composed of a plurality of elements pivotally interconnected and unfoldable from a box-like structure in which the elements lie for transportation. Each modular unit comprises a base member to engage the ground, a wall panel, first pivot means pivotally mounting the wall panel to the base member, a roof panel, second pivot means pivotally mounting the roof panel to the wall panel at a location distal from the first pivot means, a first bracing strut for connection by one end to the wall panel adjacent the base member, and a second bracing strut for connection by one end to the other end of said first bracing strut, the other end of the second bracing strut being for connection to the roof panel adjacent the edge thereof distal from the wall panel, and the base member consisting of a framework dimensioned to accommodate the panels within it. The roof panel is foldable about the second pivot means to lie substantially against the wall panel and the wall panel is foldable about the first pivot means to lie, with the roof panel, within the framework which has a box-like form.

Description

SPECIFICATION Improvements in or relating to building structures This invention relates to building structures and in particular to building structures that are readily erectable from basic components occupying little space. Such readily erectable structures may have a wide variety of uses and applications, a particularly important one (though by no means exclusive) being to provide emergency housing, e.g. following a disaster or catastrophe.

According to one aspect of this invention there is provided a modular unit for co-operation with at least one other like modular unit for use in the ready erection of a building structure, said modular unit being characterised by: (a) a base member to engage the ground, (b) a wall panel, (c) first pivot means pivotally mounting the wall panel to said base member, (d) a roof panel, (e) second pivot means pivotally mounting the roof panel to said wall panel at a location distal from said first pivot means, (f) a first bracing strut for connection by one end to said wall panel adjacent said base member, (g) a second bracing strut for connection by one end to the other end of said first bracing strut, the other end of said second bracing strut being for connection to the roof panel adjacent the edge thereof distal from said wall panel, and being further characterised in that said base member comprises a framework dimensioned to accommodate said panels within it, said roof panel is foldable about said second pivot means to lie substantially against said wall panel, and said wall panel is foldable about said first pivot means to lie, with said roof panel, within said framework.

Preferably at least one further bracing strut is provided for connection by its one end to said first and/or said second bracing strut and by its other end to mounting means therefor provided on said roof panel at a location adjacent said wall panel, said mounting means including a plate-like extension to overlie said wall panel and be selectively secured thereto to lock the panels to one another in their unfolded state.

Preferably said second pivot means comprises a hinge at each side of the panels, each such hinge comprising a pair of right-angle bracket members and a hinge pin, each rightangle bracket member comprising a first planar portion to overlie the side surface of a said panel and a second planar portion to overlie the internal major surface of a said panel, said hinge pin interconnecting adjacent edges of the two said second planar portions.

For erecting a building structure, a pair of such modular units are secured together with the two said first pivot means remote from one another and their pivotal axes parallel to one another, the panels are unfolded from the two modular units and the two roof panels interconnected at their ends remote from their respective second pivot means thereby to form the four panels into an archway.

First and second such pairs may be disposed laterally adjacent one another, the side edges of all said panels being provided with a re-entrant groove and the space between said laterally adjacent pairs of modular units being sealed by a sealing strip of somewhat mushroom-like cross-section having a "dome" to overlie the space and form a compression seal against the external surface of laterally adjacent panels and having "stalk" provided with lateral projections to enter the said grooves.

Preferably said sealing strip cross-section includes a "tail" portion depending from said "stalk" and to extend inwardly of the structure.

Preferably said lateral projections comprise an upper pair of oppositely directed lips and a lower pair of oppositely directed lips.

By way of non-limiting example, one embodiment of the present invention will now be described with reference to the accompanying drawings of which: Figure 1 is a schematic perspective view of an erected building structure embodying this invention.

Figure 2 is a similar view of the building structure of Fig. 1 in the course of erection, Figure 3 is a view partly in section and partly in end elevation of the erected building structure of Fig. 1, Figure 4 is a schematic perspective view illustrating how the base members of modular units according to this invention may be interconnected, Figure 5 is an enlarged view of part of Fig.

3, Figure 6 is a view in the direction of arrow V1 of Fig. 5, Figure 7 is an exploded schematic perspective view showing parts of modular units embodying this invention.

Figure 8 is a view in the direction of arrow V1 11 of Fig. 7, Figure 9 is a cross-sectional view along the line 1X-1X of Fig. 8, Figure 10 is an exploded cross-sectional view showing parts of modular units embodying this invention, Figure 11 is a plan view of part of a roof panel of a modular unit according to this invention taken along the line X1-X1 of Fig.

12, Figure 12 is a cross-sectional view along the line X11-X11 of Fig. 11, Figure 13 is a schematic perspective view showing parts of modular units embodying this invention, Figure 14 is a schematic end elevation of parts of the illustrated embodiment, and Figure 15 is a schematic perspective, partly sectioned view of part of the illustrated embodiment.

In the accompanying drawings, not all the Figures are to the same scale.

The building structure 1 illustrated schematically in Fig. 1 is composed of a plurality of pairs of like modular units 2 disposed laterally adjacent one another. The laterally adjacent pairs 2 form an elongate building, each pair of modular units 2 forming an archway. The ends of the elongate building structure 1 are each closed off by an end panel 3 (Fig. 3) fitting within the end archway and by a tentlike awning 4 extending away from the side edge of each end archway (see Fig. 1).

It will be seen from Fig, 2 which shows the modular units 2 in both closed or folded-up state and in partially erected state, that each modular unit 2 comprises a base member 5 to engage the ground, a wall panel 6 pivotally mounted adjacent its lower edge to an end of the base member, and a roof panel 7 pivotally mounted to the upper edge of the wall panel 6, the base member 5 comprising a box-like framework which accomodates the wall panel 6 and roof panel 7 when these two panels are folded up.The pair of modular units 2 forming an archway are provided by securing together the two box-like frameworks 5 end to end, i.e. with the pivoted mountings to their respectively associated wall panels 6 remote from one another (but their pivoted axes mutually parallel), and interconnecting the two roof panels 7 adjacent their uppermost edges 8 by means of central extension members 9 which space apart said uppermost edges. The spacing or longitudinal opening 10 thus created between said uppermost edges 8 provides a skylight entrance of light into the interior of the building structure 1, and this opening 10 may be covered by attaching a strip of transparent flexible roofing material to said uppermost edges 8 (preferably both on the exterior and interior of the building structure 1 to provide for insulation and/or to counter any condensation tendency).

The erected archway formed by a pair of said modular units 2 is rendered rigid by the provision of tubular steel bracing struts for the panels 6, 7 of each unit and locking said panels 6, 7 together in their unfolded state to render ineffective the pivotal connection between them. As most clearly shown in Figs. 2 and 3, the bracing struts of each unit 2 comprise: a first strut 11 extending in the vertical plane centrally of the wall panel 6 and connected by one end 1 2 to the outer face of wall panel 6 at its bottom adjacent the base member 5; a second bracing strut 14 extending in the said vertical plane centrally of the panel 7, and connected by one end 1 5 to the upper free end 1 3 of strut 11 and by its other end 1 6 to the outer face of roof panel 7 adjacent its top edge 8; and two further short struts 1 7 extending laterally in opposite directions from the junction 1 8 of struts 11, 14 to mounting brackets 1 9 (see Fig. 8) laterally spaced apart on the bottom edge portions of the roof panel 7. A further pair of short bracing struts 21 are connected to strut 11 in.

between its ends 1 2, 1 3 and to laterally spaced locations on the wall panel 6, and a still further pair of short bracing struts 24 are connected to strut 14 in between its ends and to laterally spaced locations on the roof panel 7.

As shown in Fig. 3, the building structure is provided with a floor covering comprising floor panels 20 that are mounted on the framework of base member 5, when the building structure is in its erected state. These floor panels 20 are in fact removable side faces of the modular units (see Fig. 1) each panel 20 providing a cover member of the box-like framework 5 when the unit is in its folded-up state for transportation or storage. Each boxlike framework comprises two opposed end walls 22, 23 provided by the bights of steel beams 25, 26 of generally U-shaped cross section. When two modular units are placed together for forming an archway the end walls 23 are in surfacial abutment with one another and are secured to one another by steel Ushaped clips 28 (Fig. 4) inserted into slots 27 provided in the limbs of the abutting beams 26.The clips 28 are provided with notch-like cut-outs 29 in one edge which can accomodate the ends of the slots 27. Thus each clip 28 can be inserted downwardly into the pair of adjacent slots 27 to hold the two base members 5 together, and each clip is then locked in this holding position by being moved laterally so that the ends of slots 27 enter into the notch like cut-outs 29.

Each U-section beam 25 (more clearly shown in Figs. 5 and 6) is provided adjacent each of its two ends, i.e. adjacent the sides of the box-like framework of base member 5, with a pair of vertical webs 31 welded to the end wall 22 and to the upper and lower limbs 32 and 33 of beam 25 internally of the beam. A bolt 35 extends through each pair of webs 31 to provide a pivotal axis and pivotal support for a panel 6. The panel 6 is mounted on the two bolts 35 via generally U-shaped bracket 34 screwed to the bottom edge of panel 6, both limbs of each bracket 34 being disposed within the two webs 31 of its respective mounting. The two ends of U-section beam 25 are closed off by welded on end plates 36 and, adjacent these end plates 36, the bight wall 22 of the beam 25 is provided with slots 37. These slots 37 are similar to slots 27 and likewise receive U-shaped clips such as 28 for securing together the base member 5 of two laterally adjacent modular units 2.

As indicated by Fig. 7, the panels 6 and 7 are pivotally mounted to one another by hinges 38 at the two side edges of the panels.

Each such hinge 38 comprises a pair of rightangle bracket members 39 and a hinge pin 40. Each right-angle bracket member 39 comprises a first plate 41 to overlie (i.e. surfacially abut against) the side surface of the respective panel 6, 7 and be screwed thereto by three screws 43, and a second plate 42 to overlie (i.e. surfacially abut against) the internal major surface of the respective panel 6, 7 and be screwed thereto by five screws 45. The hinge pin 40 interconnects the adjacent edges of the plates 42, and provides a pivotal axis for panel 7 relative to panel 6 that is parallel to the horizontal pivotal axis for panel 6 relative to base member 5 provided by bolts 35. It will be appreciated that the hinges 38 are thus capable of resisting and/or withstanding torsional forces in two orthogonal planes.

Fig. 8 illustrates schematically from the exterior the upper laterally adjoining portions of two modular units 2 and shows the righthand mounting bracket 1 9 of the modular unit 2 on the left-hand side, and the left-hand mounting bracket 1 9 of the modular unit 2 on the right hand side. It will be appreciated that the bracing struts 1 7 are cranked at their lower ends, the lower short cranked portion being retained pivotally in a bushing 43 welded to the outer corner of an angle bracket member 44 (see also Fig. 9). The angle bracket member 44 has a short upper limb 47 screwed onto the exterior major surface of roof panel 7 and a longer lower limb 46 screwed onto the edge of roof panel 7.The length of limb 46 is such that it projects downward beyond the interior surface of roof panel 7 (when the panels 6, 7 are in their unfolded state) and this projecting portion is provided with a vertically elongated hole 48 through which a locking screw 45 can be inserted and screwed into the wall pahel 6. In this manner the roof panel 7 not only provides a rigid support for the bracing struts 1 7 via the mounting brackets 1 9 but the latter also provide a rigid location for the locking mechanism provided by parts 44-46 and 48 that in effect (after erection) nullifies the pivots provided by hinges 38 and render roof panel 7 firmly located on the top of wall panel 6.A self-adhesive sealing strip 49 of foamed material extends laterally along the top edge of wall panel 6 to seal between that top edge and the overlying portion of the roof panel's interior major surface (see Fig. 9). Another sealing strip 50 (Fig. 8) extends over and between the facing side edges of laterally adjacent roof panels 7 and laterally adjacent wall panels 6, the outer bottom arris of the roof panels 7 being provided with a rounded selvedge 51 at said side edges so as to provide a smooth transition for the sealing strip 50 as the latter changes direction between the roof panels 7 and the wall panels 6.

It will be apparent from Figs. 5, 6, 7 and 10 that each panel 6 and 7 comprises a basic, generally rectangular wooden frame having plywood sheets 53 attached to the inner and outer surfaces of the frame, the space between the sheets being filled with a thermal insulating material 54, e.g. glass wool. The wooden side pieces of the frames 52 are provided with a re-entrant groove 55 (as by a routing operation) e.g having a crosssection akin to the sector of a circle, ie. an arcuate portion joining the ends of two straight portions that approach one another as they approach the mouth of the groove. The sealing strip 50 is a generally hollow extrudate of a resilient natural or synthetic rubber or other elastomeric material.The cross-sectional shape of the extrudate provide a domelike portion 56 having a crescent-shaped cross-section and a stalk-like portion 57 having an edge-sealing surface 58 that, in the unstressed state, lies generally parallel to the underside of portion 56, an upper pair of oppositely directed laterally projecting lips 59 directed, in the unstressed state, upwardly and outwardly of the "stalk", a lower pair of oppositely directed laterally projecting lips 61 directed, in the unstressed state, upwardly and outwardly of the "stalk", and a centrally depending tail portion 60 having a bulbous beading 62 at its lowermost edge.

In use, the sealing strip 50 is manoevered externally so that tail portion 60 enters the space between two laterally adjoining roof panels 7 and wall panels 6. The tail portion 60 is then gripped internally and pulled inwards so that the oppositely directed lips 59 enter the mutually facing re-entrant grooves 55 of the laterally adjoining panels.When the strip 50 is in this position along its entire length, i.e. over half the archway (which half is provided by two laterally adjoining, erected, modular units 2), the tail portion 60 is pulled still further inwards of the archway so that dome portion 56 is pulled firmly down into tight compression sealing engagement of the outside major surfaces of the laterally adjoining panels, surface 58 seals compressively against the side edges of the panels outwardly of the re-entrant grooves 55, lips 61 are pulled out of the grooves 55 and seal against the side edges of the panels inwardly of the re-entrant grooves 55. and lips 59 enter the re-entrant grooves 55 and seal against their mouths.The spaces formed between the individual sealing surfaces provide air insulation and/or counter any tendency for condensation to form, the dome-portion 56 providing the main weather seal between the archways.

It will be appreciated that the sealing strips for the two archway halves are only inserted after said halves have been assembled and erected to form the laterally adjacent archways. For this, each roof panel 7 is provided with the extension member 9 disposed centrally at the upper free edge of each panel 7.

Each extension member 9 has two laterally offset fingers 63 and slots 64, the latter accomodating the fingers 63 of the roof panel 7 of the other archway "half" (see Figs. 11 8 12). The fingers 63 are provided with aligned holes 65 through which a clamping bolt (not shown) can be passed to couple together the four interdigitating fingers 63 provided by the two extension members 9 of the archway's two roof panels 7. The two upper corners of each roof panel 7 are provided with rightangle brackets 66 (see Fig. 1 3) each having one limb 67 screwed to the upper edge of the panel 7 and its other limb 68 provided with a hole 69 through which a bolt (not shown) can be passed for securing together laterally adjacent roof panels 7.Since there is no need for a sealing strip 50 at the outwardly facing side edges of the end archways of the building structure 7, it might be thought that the reentrant grooves 55 provided in these side edges were redundant and of no use. However it is preferred in this embodiment of the invention to make use of these selfsame reentrant grooves 55 as retaining means for the tent-like awning 4. To achieve this the flexible awning material is provided with a thickened beaded edge portion 70 (e.g. as by wrapping the material edge around a cord and mutually bonding overlapping material portions), and this beaded edge portion 70 is slid into and along the re-entrant grooves 55 (Fig. 14).

When the awning material is tautened in the arrowed direction of Fig. 14, e.g. as by guy ropes, the bead 70 seals against the mouth of the re-entrant groove 55.

Fig. 15 illustrates schematically the form of the floor construction of a modular unit 2. The U-section steel beams 25, 26 are interconnected by two wooden side panels 71. Two Lshaped brackets 72 are secured at spaced intervals to each side panel 71, with the horizontal limbs 73 of the "L" lowermost and directed in pairs towards one another across the box 5. When the modular unit 2 is in its folded up state, the floor panel 20 is releasably secured to these four horizontal limbs.

When the modular unit 2 is erected, the floor panel 20 is temporarily removed and two Usection beams 74 positioned across the box 5 and secured by their ends to the two pairs of aligned horizontal limbs 73 of the brackets 72 such that the limbs of beams 74 are directed vertically upwardly. Pairs of transverse webs 76 are welded to the beams 74 at each of four locations spaced along each beam 74 such that the webs 76 and the limbs of beams 74 form together eight separate rectan gular sockets. A wooden post 75 of rectangu lar section is inserted into each socket, the post 75 fitting between each pair of webs 76 and overlapping the limbs of beams 74. Such overlapping is facilitated by the provision of transverse saw-cuts 77 across the underside of each post 75.

The upper surface of each post 75 is provided with a projection 78 of rectangular section that fits into a correspondingly shaped aperture 79 in the floor panel 20 whereby thed latter fits onto the posts 75 in the manner of .

eight ortise-and-tenon joints.

The building structure has the two end walls 3 located inwardly of the respective end awnings 4 and within the respective end archways. Location of each end wall 3 is merely by a plurality of wedges (not shown) hammered into the arch-like space between the external perimeter of end wall 3 and the adjacent inner surfaces of the two opposite roof panels 7 and the two opposite wall panels 6. Thus each end wall 3 provides no more than a tolerably effective wind barrier and thermal insulator (providing no structural function), and rain and snow weatherproofing is provided by the awnings 4 and their abovedescribed attachment to the end archways.

Advantageously each end wall 3 is formed of two trapezium-shaped halves that are interconnected along the centre line, each half being hinged horizontally so as to be foldable to dimensions comparable to those of a modular unit 2.

Advantageously each wall and roof panel 6, 7 has each of its inner and outer surfaces of 4 mm plywood attached peripherally to the frame members 52 and compressed towards one another centrally of the panel by a bolt device. This central compression prestresses the plywood surfaces and thereby improves the rigidity and stiffness (particularly torsional stiffness) of the complete panel.

In a preferred form each panel 6, 7 has dimensions 1.27 m X 1.7 m X 0.068 m (width X height X thickness) and each box like base member 5 that contains the two panels 6 and 7 has dimensions 1.295 m X 1.950 m X 0.190 m (laterla width X length X height). it will be apparent that after allowing 0.136 m for the thickness of the two panels 6, 7 and, say, approximately 20 mm for the thickness of the waterproof chipboard floor panel 20, a height of over 30 mm is still available within the box 5 to accomodate the tubular steel bracing struts, the floor support parts, various other parts (e.g. bolts) and a hammer, a spanner and a screw-driver, these last three being the only tools required for effecting erection of the illustrated building structure 7. It will be ap parent that, with the above-mentioned dimen sions, a single archway formed of two erected modular units 2 would have dimensions 1.295 m X 3.90 m X 2.46 m (lateral width X archway breadth X height) so that a building structure 1 composed of six arch ways side-by-side (i.e. employing twelve mo dular units 2) would have a total length in excess of 7.7 m, provide cover for a floor area in excess of 30 m2 and enclose a habitable volume of approximately 55 m3, the twelve modular units 2 required to provide this being packagable (in the folded-up state) to occupy a cube shape of length 3.00 m, width 1.15 m and height 1.95 m, i.e. a cubic packed volume of 6.72 m3.

From the foregoing it will be apparent that each modular unit 2 includes a floor panel 20, and a wall panel 6 and a roof panel 7 stably connected by hinges, so that in the collapsed state the unit 2 forms a rigid, rectangular box which can be transported by two people, but in the unfolded erected state the wall and roof panels 6,7 are held together by means of externally-applied, wind-resisting bracing struts 11, 14, 1 9 to form half of a rigid three-hinged archway. In the erected state the two modular units 2 lying opposite each other and connected to each other by a simple bolt on the ridge, form a three-hinged archway in which the forces in the external wind-resisting bracing struts of steel tubing and the forces in the wall and roof panels are in equilibrium.

The shelter or building structure 1 is made up by the free addition of the basic modules 2 which, when fixed to each other, result in a tunnel-like, linear, structure of any desired length. However, since the two roof panels lying opposite each other do not touch along their whole width but are only bolted together in the centre by a protruding connection piece 9, and intermediate space of approximately 20 cm width is left which ensures natural lighting inside the structure. This open strip of light is covered by a translucent plastic strip.

From the foregoing it will also be appreciated that the illustrated building structure 1 can be erected without specialist labour, by only two people, from the ground, ie. without scaffolding and without having to climb on to the roof, and with only a hammer, a spanner and a screw-driver as tools. The erection procedure requires that all the modular units 2 be laid out in the folded-up state next to each other in pairs on a flat area and be then fixed together with the simple clips 28 in slots 27, 37 so that the modular units 2 are all connected and immovable.A first unit 2 is unfolded from its box 5 in the sense that the wall and roof panels 6, 7 (which are fixed to each other and to the bottom of the box with hinges) are unfolded to form a tempoary "cor net'' which allows the steel tubes of the bracing struts lying in the box 5 to be bolted at 1 8 to the swing-out clamps 1 9 already fixed to the roof panel 7 and to the wall and roof panels 6,7 in such a way that half of a rigid three-hinged archway is formed. The opposite modular unit 2 is unfolded and is botled together in the same way to form the other symmetrical half of the three-hinged archway.

The two rigid pairs of panels 6, 7 facing one another are now lifted to an upright position and bolted together by means of the connection pieces 9 protruding from the two roof panels 7 so that a complete three-hinged archway is formed. One three-hinged archway 7 is erected after the other until the shelter or building structure 1 is complete. Any levelling differences which may arise (from the irregu larities of the ground) in the lateral connection of one modular unit 2 to the next can be corrected by designing the two hinges which connect the wall and floor panels 6 and 5 in such a way that they allow for vertical play and/or by ensuring that the roof elements (despite their prestress) have adequate elasti city to allow them to be bolted to the adjacent roof panels.

It will thus be seen that the illustrated embodiment of this invention provides a sim ple construction system for the modular con struction of temporary shelters with variable volume, consisting of floor, wall and roof elements which are hinged together and which can be bolted together to form a three hinged arch by the attachment of external wind reinforcement and thereby form the ba sic module of a tunnel-like, linear shelter of unlimited length. The hinged basic elements can be joined together in such a way that they form a transportable, self-protected container which needs no additional packaging. Due to their construction, the prestressed, insulated wall and roof panels 6, 7 of lightweight material have a special torsional stiffness.Also it will be appreciated that by means of the above described embodiment of the invention, populations in need, for example after natural, environmental or war catastrophes or in the event of short-term evacuation of groups of the population, can be supplied within a short time with provisional shelter which can be put up by those affected without outside help, and which, for a limited period, can offer suitable protection against temperature and weather conditions, (exceeding that of tents which are generally used in such circum stances). Furthermore the illustrated building structures can also be used in the field of leisure and sport, e.g. for holiday camps, youth camps, etc.In contrast with the above described and illustrated embodiment of the present invention, prior proposals in the field of lightweight, prefabricated, temporary shel ters, which are not tent structures, provided, in general, a central structure which cannot be varied in size even by the addition of ele ments, or provided a complex system of remo vable elements or of non-identical basic ele ments, or provided that the basic elements could not be put together simply to form a transportable container.However the above described and illustrated embodiment of the present invention differs fundamentally from previously proposed building structures in that it provides means for quick and simple execution of a protective shelter, in that erection needs no specialised technicians, and in that it is a modular construction system consisting of stable load-bearing elements which allow rooms of varying dimensions to be built. Furthermore the illustrated embodiment of this invention is characterised by the fact that, with the exception of the two end panels of the shelter, all indivisible elements are identical and therefore make erection considerably easier, especially in view of the fact that the elements can be exchanged and no special sequence of erection has to be followed.

Moreover, the illustrated system offers the advantage that no special packaging materials are required, which would increase the total weight, and the elements, when folded up are to a large extent protected from external damage.

Claims (9)

1. A modular unit for co-operation with at least one other like modular unit for use in the ready erection of a building structure, said modular unit being characterised by: (a) a base member to engage the ground, (b) a wall panel, (c) first pivot means pivotally mounting the wall panel to said base member, (d) a roof panel, (e) second pivot means pivotally mounting the roof panel to said wall panel at a location distal from said first pivot means, (f) a first bracing strut for connection by one end to said wall panel adjacent said base member, (g) a second bracing strut for connection by one end to the other end of said first bracing strut, the other end of said second bracing strut being for connection to the roof panel adjacent the edge thereof distal from said wall panel; and being further characterised in that said base member comprises a framework dimensioned to accommodate said panels within it, said roof panel is foldable about said second pivot means to lie substantially against said wall panel, and said wall panel is foldable about said first pivot means to lie, with said roof panel, within said framework.

2. A modular unit according to Claim 1, wherein at least one further bracing strut is provided for connection by its one end to said first and/or said second bracing strut and by its other end to mounting means therefor provided on said roof panel at a location adjacent said wall panel, said mounting means including a plate-like extension to overlie said wall panel and be selectively secured thereto to lock the panels to one another in their unfolded state.

3. A modular unit according to Claim 1 or Claim 2, wherein said second pivot means comprises a hinge at each side of the panels, each such hinge comprising a pair of rightangle bracket members and a hinge pin, each right-angle bracket member comprising a first planar portion to overlie the side surface of a said panel and a second planar portion to overlie the internal major surface of a said panel, said hinge pin interconnecting adjacent edges of the two said second planar portions

4.A pair of modular units, each according to any preceding claim and having their base' members secured together with the two said first pivot means mutually distant but their pivotal axes mutually parallel, said panels being unfolded, and the two roof panels being interconnected at their ends remote from their respective second pivot means such that the four panels form an archeway.

5. A building structure comprising first and second pairs of modular units each according to Claim 4 and disposed laterally adjacent one another, the side edges of all said panels being provided with a re-entrant groove and the space between said laterally adjacent pairs of modular units being sealed by a sealing strip of somewhat mushroom-like cross-section having a "dome" to overlie the space and form a compression seal against the external surface of laterally adjacent panels and having "stalk" provided with lateral projections to enter the said grooves.

6. A building structure according to Claim 5 wherein said sealing strip cross-section includes a "tail" portion depending from said "stalk" and to extend inwardly of the structure.

7. A building structure according to Claim 5 or Claim 6 , wherein said lateral projections comprise an upper pair of oppositely directed lips and a lower pair of oppositely directed lips.

8. A modular unit according to any one of Claims 1 to 3, a pair of modular units according to Claim 4, or a building structure according to any one of Claims 5 to 7, wherein the or each said modular unit comprises a panel selectively to form a removable covering for said framework when the latter accomodates the folded-up roof panel and wall panel or to form a floor panel upon said framework when the said roof panel and wall panel are unfolded and in their erected condition.

9. A modular unit, a pair of modular units to form an archway, or a building structure, substantially as herein described with reference to and/or as illustrated in the accompa- - nying drawings.