STRUCTURE

Abstract: A housing structure (1) comprising a plurality of prefabricated wll panels (2) and a frame (3), wherein the panels (2) comprise a thermally insulating material (22) sandwiched between parallel plates (21). The structure may be seismic resistant.

Description: STRUCTURE DESCRIPTION This invention relates to a structure and, more specifically, to a low cost structure which can be assembled with little or no technical acumen and in a number of environments. It is well established that housing represents a significant fiscal burden to all but the most affluent of society. In many places around the world, families are forced to construct homes from, for example, waste materials discarded by others due to their economic and/or political disenfranchisement. Moreover, in times of environmental catastrophe, such as floods, earthquakes, volcanoes, hurricanes and so on, many people are dislocated due to damage to their homes. In such conditions, it is necessary to provide emergency shelter, such as tents, to facilitate survival. In order that the individuals involved do not end up spending an inordinate amount of time in this temporary accommodation, it is desirable to construct more resilient housing at the earliest convenience. Obviously, the provision of such housing can only be considered once the environmental factor has receded - the storms have abated, the flood dispersed or the aftershocks have ceased for example - and once suitable sites have been selected and cleared or prepared. In the aftermath of an environmental disaster, a number of interest groups are often involved in the re-building of an area. These may involve central and local governments, insurers, "big business", charitable organisations and inter-governmental organisations such as the United Nations. The conventional onus has not been on making the temporary sites "more permanent" but rather to make the people using such temporary accommodation as comfortable as possible, whilst attempting to re-build the affected area completely. Conventional reconstruction theory considers it desirable that like should be rebuilt with like. However, due to the economic situation in the affected region this may not be possible. If the affected area is in the United States of America, for example, it is likely that most of the affected individuals will have insurance which will allow a house to be rebuilt or an equivalent purchased. In certain areas of the World however, it is much less likely that insurance is maintained on homes and these impoverished individuals lose everything during and after such crises. If it is impossible to replace the destroyed housing stock with like-for-like, then a cheaper alternative, which can be constructed speedily, must be found. Conventionally, cheap, alternative housing has not been as resilient as the housing which it replaced and, consequently, it has been seen as temporary at best. Accordingly, it is an object of the present invention to provide an easy to produce housing structure, conforming to building regulations and standards, which affords the resident a warm, stable, resilient structure which is cheaper than other forms of replacement housing and can be constructed without heavy or specialised machinery. It is another object to provide a housing structure which can be constructed after an environmental disaster, such that affected individuals are housed in resilient structures which can be inhabited for extended periods. According to a first aspect of the invention, there is provided a housing structure, preferably temporary, comprising a plurality of prefabricated wall panels and a frame, wherein the panels comprise a thermally insulating material sandwiched between parallel plates. A second aspect of the invention provides a seismic resistant housing structure, preferably temporary, comprising a plurality of prefabricated wall panels and a frame, wherein the frame is emovably connected to a laid concrete foundation. The thermally insulating material is preferably an expanded polyurethane foam with a density greater than 25 kg m "3 , and more preferably a density in the range of 35 to 45 kg m "3 . The parallel plates preferably comprise a metal, which may be steel provided with a protective coating such as a plastics, for example polyester, lacquer and a polyvinyl chloride film. The wall panels preferably have a thermal conductivity (k-value) of less than 1.5 kJ nϊ^hr "1 , and more preferably still of 1.3 kJ m " hr " . The frame preferably comprises a plurality of members which support and retain the panels, preferably forming a monocoque structure. The panels may comprise a groove or slot and a correspondingly-shaped tongue provided on opposed respective edges thereof, such that, upon construction, a tongue of a panel engages a groove or slot of an adjacent panel. The structure may comprise a roof formed from a plurality of roof panels. Each panel may be formed with an upper surface provided with a plurality of peaks and troughs to facilitate drainage from the installed roof. The peaks and troughs may provide a castellated or sinusoidal cross-section.. A third aspect of the invention provides a method of constructing a housing structure from a plurality of prefabricated wall panels and a frame, wherein the panels comprise a thermally insulating material sandwiched between parallel plates, comprising the steps of: levelling an area to provide a horizontal working surface with a minimum soil resistance of 5 N cm "2 ; digging a peripheral trench and installing a foundation therein; and constructing the housing structure from the panels and frame. Embodiments of the inventive structure will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 shows a front elevation of a housing structure; Figure 2 shows a plan view of the structure shown in Figure 1; Figure 3 shows an isometric cutaway view of the frame of a further housing structure; Figure 4 shows a cross-section of a lower frame member and a wall panel; Figure 5a shows a plan view of a "T-shaped" joining frame member; Figure 5b shows a plan view of a corner joining frame member; Figure 6 shows a cross-section view through an installed wall and roof panel; Figure 7 shows a cross-section through an installed roof at the roof ridge; and Figure 8 shows an isometric view of a ridge member. Referring firstly to Figures 1, 2 and 3, there are shown structures, generally indicated at 1 and la, comprising a plurality of standard size wall panels 2, a plurality of joining sections or frame members 3, gable panels 4 and a plurality of roof panels 5. Each structure 1, la is mounted upon a concrete foundation and is provided with prefabricated door 7 and window units 8. As shown in Figure 4, each wall panel 2 is formed by two steel plates 21 joined by high-density rigid polyurethane foam 22. Each steel plate 21 may be galvanised and lacquered with an epoxy resin base coat and a polyester silicone lacquer and finished with a protecting film, or it may be a steel plate finished with an aluminium-zinc alloy. Each plate 21 weight is of the order of 185 g m "2 . The polyurethane foam 22 may be of a density of 40 ± 5 kg m "3 and may contain fireproofing and stabilising agents. The foam 22 is preferably blown using pentane. The denser the foam 22, the better the insulating property of each panel 2. Indeed, the thermal conductivity or k-value is preferably less than 1.5 kJ m "2 hr _1 , although if the foam 22 has a density of 40 kg m "3 , the k-value is about 1.3 kJ m "2 hr " \ The roof panels 5 typically have similar core foam densities and k- values to those of the wall panels 2, although in some cases a k-value of 1.9 kJ m^hr "1 , with a core foam density of 30 kg m "3 may be utilised. The gable panels 4 are similarly formed from steel plates joined by high-density polyurethane foam, as are the roof panels 5. However, the plates of the roof panels 5 which are presented uppermost once installed, as at 51, are formed with regular trapezoidal trenches 52 to facilitate adequate drainage of water. The frame members 3 are constructed from extruded aluminium which are lacquered with a polyurethane paint to finish and protect the surfaces thereof. The components are fixed together, as is described below, by rivets 6 or screws, the rivets 6 preferably being fabricated from aluminium. To manufacture a panel 2, the steel from each of two rolls, mounted in parallel, is delivered from a mounting means to a cold-rolling machine where it is shaped as it passes through cylindrical rolls to the required dimensions. The lower steel plate is heated and the polyurethane foam is evenly distributed thereon. The steel plates are delivered such that they are parallel with respect to one another and at the same speed. Theoretically, by this continuous process, any length of panel can be made but, due to transport limitations, the panels 2 are usually cut to a maximum length of 16 m. The panels 2 are pressed, so as to provide a constant thickness panel, and are then left to allow the foam 22 to mechanically and chemically stabilise, at a constant temperature, for a period of time determined by the desired thickness of the panel, but usually about 10 hours. Once the panels 2 have stabilised, the edges thereof are milled to provide a panel of the desired measurements. Opposed longitudinal edges are provided with a tongue 28 and groove 29 respectively such that once assembled, adjacent panels can engage one another in a mating relationship and to ensure that at the abutment of two panels 2 a "cold-bridge" is not formed. As previously stated, opposed faces of the plates 2 are lacquered and they may also be provided with a contoured finish on one or both surfaces. The interior and exterior wall panels 2 are produced such that they have an identical width and thickness, irrespective of their function within the completed structure. Thus, for example, all of the panels for a 57 m 2 structure 1 will be 6 cm thick and 114 cm wide. The height of the individual panels 2, or the provision of apertures therein, will be determined by the role of each respective panel in the assembled structure. The roof panels 5 are manufactured according to the method of manufacture utilised for the wall panels 2. However, one of the steel sheets, the one produced with rows of regular trapezoidal waves 52, is first sent through a machine to form the waves 52. This sheet is then delivered to the panle forming machine not in rolls but rather in set lengths. The sheet provided with the trapezoidal waves forms the upper sheet 51 of the roof panel 5, which is to say the externally facing sheet once the structure 1, la has been assembled. The roof panels 5 may be up to 10 cm thick at their extreme and, due to their large inertia, only require fixing at a few points once installed. In contrast to the method of production of the wall 2 and roof 5 panels, the gable panels 4 are not continuously produced. Rather, profiles and steel plates are placed in special presses which have the shape of the panels 4 and the press is closed. The polyurethane foam is injected through a small aperture at the side of the press and it is evenly spread between the two plates. Once the foam has evenly spread between the two plates, the gable panels 4 are allowed to rest so that the foam may stabilise. The angle formed by the slope of a gable panel 4 is altered depending upon the model of structure 1, 1a desired. The frame members 3 are constructed by passing aluminium through an extrusion machine and then cutting the extruded material to determine the required length of member 3. The edges of each member 3 are conditioned to guarantee that the dimensions are within the specified limits and that each makes a perfect fit in the final position. The members 3 are drilled, polished and lacquered with, for example, a polyurethane or other finishing paint to achieve a perfect external look. The members 3 are formed in a variety of shapes and sizes depending upon which part of the structure they are. to be used in and for. As shown in Figures 3 and 4, the base frame member 31 comprises a pair of opposed longitudinal side walls 310, 311, joined by a longitudinal base wall 312. Each of the side walls 310, 311 is provided with a lateral longitudinal- support 314 which, in combination, support the base of an , inserted panel 2. The side walls 310, 311, at regular positions along ' the length thereof, such as every 300 mm, are provided with apertures, through which rivets 6 can be thrust. The base wall 312 is similarly provided, at points along its length, with apertures 317. The external side wall 311 of the base frame member 31 is provided with a longitudinal cavity or recess 318 of rectangular cross-section. The recess 318 is provided with upper and lower flanges 319 each with a sloping surface facing in the general direction of side wall 311. Referring now to Figures 3, 5a and 5b, joining frame members 33 and 35 are shown. The corner frame member 35 is provided with a bore 350 of substantially square cross-section and two slots 351 each defined by a pair of vertical parallel walls 352. The slots 351 are so-dimensioned that they can accept an edge of a wall panel 2. Similarly, the T-shaped edge frame member 33 is provided with a bore 330, and three slots 331 each defined by a pair of vertical parallel walls 332 such that each slot 331 can accept an edge of a wall panel 2. As can be seen from Figure 3, the T-shaped member 33 is used to provide joining means at the point at where an internal wall panel abuts an external wall panel 2, and the corner member 35 is utilised at an external wall corner. The walls 332, 352 of each member 33, 35 respectively are pre-drilled at points along their length in order that rivets 6 may be thrust therethrough to facilitate the construction of the structure 1. In order to secure the roof panels 5 to the structure 1 upper finishing frame members 37, as shown in Figure 6, are attached to the upper edge of the exterior wall panels 2. The upper member 37 comprises a pair of parallel side walls 370 and 371 and a sloping upper wall 372 interconnecting the side walls 370, 371. The side walls 370, 371 are pre-drilled at regular positions along their length to provide apertures 375 through which rivets 6 can be thrust to secure the member 37 to an exterior wall panel 2. The interior facing side wall 370 is provided with a lateral longitudinal ledge 374 which runs the entire length of the . member 37. As shown, the upper member 37 is fitted about the top of the panel 2 such that the side walls 370, 371 embrace the top portion of the panel 2 with the ledge 374 abutting the top edge thereof. In this fashion, the sloping upper wall 372 is presented to a roof panel 5, which is secured thereto by a screw or self-tapping bolt 54. The lower base frame member 31, as shown in Figure 6, is provided with a drainage aperture 313 to allow any water which collects therein to drain to the exterior of the structure 1. In order to reduce ingress "of water through the aperture 313, a "F-shaped" member 39 is attached to the exterior wall 311 of the lower base frame member 31. To facilitate this connection; a member 38 of substantially "I-shaped" cross-section is inserted into the recess 318 of the main base member 31. The horizontal upper and lower arms of the member 38 are provided with longitudinal grooves which are engaged by the flanges 319 formed on the recess walls to secure the member 38 therein. The member 38 is so- dimensioned that once inserted the vertical body portion 381 is aligned with the external wall 311 of the base member 31. The externally facing upper and lower horizontal arms of the member 38 similarly engage the upper and lower horizontal arms of the F-shaped member 39 such that the arms of the member 39 abut the wall 311 of the lower base frame member 31. The vertical leg 391 of the F-member 39 projects below the aperture 313 of the lower frame member 31 and thereby' reduces or prevents ingress of water into that member 31. Referring now to Figures 7 and 8, there is shown a roof frame member 40 comprising a pair of vertical, parallel, side walls 401, 402 joined by a perpendicularly arranged upper wall 403. The roof frame member 40 further comprises a pair of downwardly sloping arms 404 extending from either side of the upper wall 403. Upwardly extending support members 408 extend from the side walls 401, 402 to the underside of the arms 404 to ensure that the roof member can support the weight of the roof. The walls 401, 402 are pre-drilled at positions along their length to provide apertures 405 through which rivets can be thrust to secure the roof member 40 to wall panels 2. In order to construct accommodation in accordance with the invention, it is first necessary to prepare a surface 100 where the structure 1, la will be erected. Thus, all underlying vegetation must be manually or mechanically removed and the upper layer of soil, containing organic material, must be removed to so-obtain a totally clean, flat and horizontal working surface with the minimum required soil resistance of 5 N cm "2 . The next stage of the operation is the excavation of a trench 800, 20 cm wide and 40 cm deep, corresponding to the perimeter of the floor space for locating the foundation stalls 80 therein such that they are protected from frost and erosion damage. At the same time trenches are also dug for the internal sewer system and pipe sections for the provision of water, gas, electricity and other desired services are installed in the peripheral trench. The width and depth of the trench 800 may be varied depending upon the local building site conditions. The sewer system trench is configured such that it slopes to a low point outside the periphery of the house 1, la to facilitate the drainage of sewage , therefrom. A'polyvinyl chloride sewer pipe net is installed in the sewer trench to act as the sewer pipes and it is retained in place by filling with sand, which is then compacted, as is well known in the art. Concrete foundation stalls 80 are located in the peripheral trench 800, and the whole area defined by the trench 800 is brought to a level with compacted sand. A steel plank moulding is then installed around the perimeter to guarantee a horizontal level and the desired finish to the upper surface of the lateral edges of the foundation stalls 80. At this stage, if the soil resistance is below 5 Ncm "2 , a reinforcement net or steel fibres may be installed inside the perimeter of the trench 800 to aid in the support of the structure 1. The foundation is formed by filling the plank moulding with concrete. This is leveled such that it is perfectly flat and horizontal. The upper surfaces of the foundation stalls 80 are polished manually to remove imperfections and to ensure that they are perfectly flat and horizontal to ease the later construction stages. The concrete of the foundation is allowed to "go-off' over a period of twenty four hours, if necessary by covering with plastics sheeting to ensure a slow set. Once the concrete has set the steel plank moulding is removed and cleaned such that it may be re-used. Any imperfections in the foundation stalls 80 must be repaired before assembly of the house can be attempted. Referring again to Figures 4 to 8, the lower frame members 31, which make up the base of the frame 3, are then positioned on the foundation stalls 80, such that their upper surfaces are horizontal. These lower frame members 31 are provided with pre-drilled through holes 317, through which holes 81 are drilled into the foundation stalls 80 and into which fixing bolts 85 are inserted, such that the lower frame members 31 are attached to the foundation stalls 80. If any correction is necessary to ensure the horizontal aspect of the upper surface of the lower frame members 31, galvanised steel spacer plates may be utilised. Once all of the lower frame members 31 making up the base of the frame are fixed, a corner structural member 35 is attached thereto together with two wall panels 2 in one of the corners. The corner members 35 and the wall panels 2 are maintained in a vertical aspect. The corner member 35, like the lower frame members 31, are provided with through holes, and through these, mating holes are drilled into the wall panels 2. The wall panels 2 are attached to the frame members by rivets 6 or bolts, ensuring that the wall panels 2 are vertical before such connections are made. The rest of the panels 2 are likewise installed, ensuring that adjacent tongues 28 and grooves 29 are in a mating relationship as shown in Figure 2, according to the plans of the structure provided. Thus, certain panels are provided with apertures for windows 8 and doors 7. At these apertures, the corresponding prefabricated window 8 and door units 7 are installed. The unions between the frame of the window 8 or door 7 and the wall panels 2 are waterproofed with, for example, a silicone sealant and then sealed with polyurethane foam. The window units 8 may be constructed with extruded PVC, aluminium or steel frames, as is well known in the art. The external door 7 may be constructed from a polyester framework with an insulated polyurethane injected polyester door panel and the internal door a metal frame with a pre-painted cellular structure door panel, as is well known. Once all of the wall panels 2 have been installed and the join between adjacent panels sealed with a sealant, upper frame members 37 are positioned on top of the exterior wall panels 2 ' and are fixed with rivets 6 or bolts via previously provided through holes. It is necessary to ensure that the longitudinal axes of the upper frame members 37 are horizontal. The gable panels 4 are then installed in a manner similar to that of the wall panels. A roof member 40 is installed between the apices of the gable panels 4, along the upper surface of a central wall 20, 20a, as shown in Figures 2 and 3, respectively. The member 40 is attached to the wall 20 by rivets 6 or bolts ensuring that its longitudinal. axis is horizontal. A first roof panel 5 is then installed, which has to be completed with extreme diligence as the alignment of the first roof panel determines the alignment of the whole roof. The roof panel 5 is fixed to the roof member 40 and the upper frame member 37 by means of self-tapping screws 54, after pre-drilling of the roof panel 5, and completed preferably with a drill provided with a torque-control device. The screw heads 541 are provided with a cap 542 of a plastics material to prevent the ingress of water through the pre-drilled holes. Once all the roof panels 5 are installed, the space between the panels at the roof ridge is filled with polyurethane foam 56 and ridge caps 58 and roof end members 60 are installed, by means of self-tapping screws 57, to effectively seal the joints. As soon as this stage has been completed, the structure 1 is waterproof and wind-resistant and it is ready to receive the occupants desired internal fixings and finishings. For example, the floor can be finished by gluing ceramic tiles directly to the concrete foundation or, at the occupant's discretion, parquet or laminated wooden floors can be installed. The surface of the exterior panels 2 which is presented to the interior of the structure 1, la can also be finished by applying a variety of wall coverings and decorative finishes. Interior walls, to subdivide the internal living space as shown in Figures 2 and 3, are installed similarly to the external wall installation, which is to say that lower frame members 31 according to the internal floor plan are installed after the concrete foundation has been laid. The particular interior floor members 31 used will depend on the floor plan desired, with corresponding wall panels 2, provided with the requisite apertures for doors, and completed by the necessary upper frame members. The provision of the upper and lower members braces the internal panels, adjacent ones of which are locked together by their peripheral mutual engaging means as previously described, which affords the internal wall structure a rigid nature. Indeed, the internal wall panels 200 provide structural support. The interior panels may be so-dimensioned that they exactly abut the roof panels 5 under which they stand. Alternatively, the interior panels 20, 200 may be of a height corresponding to a regular interior wall, in which case, if desired, a lightweight ceiling can be installed to confine the living space, and to further brace the internal wall structure 200 if considered necessary. For example, in order to construct a structure of 57 m 2 as shown in Figure 2, with two bedrooms 90, a living room 91, a kitchen 92 and a bathroom 93, it is necessary to have about 105.2 m 2 of panels 2 to complete the internal and external walls, 81.3 m 2 of roof panels 5, a total of 24 m 2 of gable panels 4 and 169.4 m of various lengths and shapes of frame member 3, and the required door 7 and window frames 8. The exterior walls are completed by nineteen 1.14 m wide exterior wall panels of various heights to a total area of 61.2 m 2 , and fourteen 1.14 m wide interior wall panels to a total area of 44.0 m 2 . The roof is completed by eighteen 1 m wide panels 5, and the gables 4 by eight panels, six of which are equivalent in dimensions. The internal floor plan is such that the bathroom 93 and kitchen 93 correspond with "up-points" in the sewer net. Therefore, all that is required is to install the bathroom and kitchen fittings which require a sewer outflow to the walls of those respective spaces, and connect the pipes thereto. Electricity, gas and water are supplied to the structure 1 through the conduits laid in the foundation. The cables or pipes, which carry these utilities, are simply installed along the internal walls of the structure to deliver them to the desired location. The structure 1 may be delivered with bathroom, kitchen and heating facilities ready to be installed and, in this case, the utility conduits are simply directed to the respective identified points-of-use. The external walls of the structure may be decorated according to the occupant's taste. For example, brick plates can be directly glued to the panels to give the structure the impression of a traditional construction. Also, the panels can be painted or other finishes applied to vary the texture and colour of the structure. Thus, this construction is advantageous for a plurality of reasons. In the first instance, it can be constructed very rapidly. It has been estimated that it will take 1 man-hour for each square metre of coverage, consequently, two or three people could build a 57 m 2 structure in about a day. This is further advantageous as the construction of each structure does not require a skilled work-force. The elements are constructed according to simple instructions and the "kit" nature of the flat-packed structure facilitates the ease of construction. Furthermore, no specialised machinery is required for construction and each structure may be built on a variety of soil types due to the low overall weight. The nature of the system also provides for extensions of each structure 1 as and when they are required. In order to do so, a fresh, adjoining foundation is laid and the requisite floor frame members are installed. The portion ' of the structure, which the extension is to adjoin, is partially disassembled and the necessary replacement members 3 and panels 2 are put in place. Furthermore, it is possible to co-join a traditionally constructed wall with the inventive structure 1. To do so a frame member dimensioned to accept an edged of a panel 2 is fixed to the traditional wall with a milled bolt with a steel or rubber washer. Between the member and the traditional wall a sealer is placed to waterproof the joint and avoid corrosion problems. Thereafter, construction according to the above-exemplified assembly is continued. The above-described structure 1 is obviously temporary in nature, which is to say that the whole structure can be simply unscrewed, the panels 2 removed and the lower frame members 31 unscrewed from the foundation 80. However, if a more permanent structure is required one component of a mating element can be set into the concrete of the foundation. A matching, mating element can then be connected thereto and the lower frame members 31 can then be attached to these mutually mated elements, or a layer of resin, which may be 1cm thick, can be spread over the bottom of the lower member 31 to render the fixing bolts 85 inaccessible. The accommodation structures built in accordance with the invention are not necessarily single-storey. Indeed, a multi-storey structure can be constructed from the frame members and wall panels described above. Floor supporting beams can be linked to the vertical frame members and panels 2 through adapted floor supporting members. The floor panels are suspended between the up going wall panels with specially designed load-spreading bolts. The components of the structure 1 have been designed such that the required upkeep is minimal. Basic maintenance comprises ensuring that the surfaces of the panels have not been damaged such that the anti-corrosive lacquer or coating has been removed. If the lacquer is discovered to have been damaged it can be simply repaired by cleaning the effected area to remove any grease adhering thereto and applying a proprietary lacquer. In normal use, the panels 2 can be cleaned with conventional domestic detergents which do not comprise abrasive powders or solvents, for example. The door and window units are maintenafice free, simply requiring cleaning as and when required. To affix wall lamps or other fixtures to the wall or roof panels, self- tapping screws can be used or, alternatively, such fittings may be temporarily attached with magnets. It has been calculated that three structures 1, each covering 57 m 2 , may be carried in a single container. Therefore a vast number of structures can be transported to a desired location in a short period of time. This is particularly advantageous for locations which have suffered environmental disasters, or in other situations of wide-scale and permanent dislocation of a population. In these instances a large number of cheap, high-standard structures 1 can be built in a short space of time, by the affected population, with a minimum of instruction. The structures 1 are designed to be seismic resistant, satisfying the official French and Belgium government standards. Consequently, these structures 1 are ideal for use in areas in which a large proportion of the housing stock has been destroyed following an earthquake, and there is a chance of aftershocks or other low-level seismic activity. The structures are also resistant to high speed winds (up to 240 km hr "1 ). Furthermore, areas of slum housing or so-called shanty towns can be replaced by these high-quality, low-cost, structures with a minimum of investment.

Claims: CLAIMS 1. A housing structure (1, la) comprising a plurality of prefabricated wall panels (2) and a frame (3), wherein the panels (2) comprise a thermally insulating material (22) sandwiched between parallel plates (21). 2. A seismic resistant housing structure (1, la) comprising a plurality of prefabricated wall panels (2) and a frame (3), wherein the frame (3) is removably connected to a laid concrete foundation (80). 3. A structure according to claim 2, wherein the panels (2) comprise a thermally insulating material (22) sandwiched between parallel plates (21). 4. A structure according to claim 1 or 3, wherein the thermally insulating material (22) is an expanded polyurethane foam with a density greater than 25 kg m "3 . 5. A structure according to claim 4, wherein the thermally insulating material (22) has a density in a range from 35 to 45 kg m "3 . 6. A structure according to claim 1 or any claim dependent thereon, or claim 3, or any claim dependent thereon, wherein the parallel plates (21) comprise a metal. 7. A structure according to claim 6, wherein the metal is steel. 8. A structure according to claim 6 or 7, wherein the plates (21) are provided with a protective coating. . 9. A structure according to claim 8, wherein the protective coating comprises a plastics, for example polyester, lacquer and a polyvinyl chloride film. 10. A structure according to any preceding claim, wherein the wall panels (2) have a thermal conductivity (k-value) of less than 1.5 kJ m^hr "1 . 11. A structure according to cl im 10, wherein the wall panels (2) have a k- value of 1.3 kJ m "2 hr " \ 12. A structure according to any preceding claim, wherein the frame (3) comprises a plurality of members which support and retain the panels (2). 13. A structure according to any preceding claim, wherein each panel (2) comprises a groove or slot (29) and a correspondingly shaped tongue (28) provided on opposed respective edges thereof, such that, upon construction, a tongue (28) of a panel (2) engages a groove or slot (29) of an adjacent panel (2). 14. A structure according to any preceding claim further comprising a roof formed from a plurality of roof panels (5). 15. A structure according to claim 14, wherein each roof panel (5) is formed with an upper surface (51) provided with a plurality of peaks and troughs (52) to facilitate drainage from the installed roof. 16. A structure according to claim 15, wherein the peaks and troughs (52) provide a castellated or sinusoidal cross section. 17. A structure (1, la) according to any preceding claim, wherein the structure (1, la) is temporary. 18. A method of constructing a housing structure (1, la) from a plurality of prefabricated wall panels (2) and a frame (3), wherein the panels (2) comprise a thermally insulating material (22) sandwiched between parallel plates (21), comprising the steps of: levelling an area to provide a horizontal working surface (100) with a minimum soil resistance of 5 N cm "2 ; digging a peripheral trench (800) and installing a foundation (80) therein; and constructing the housing structure (1, la) from the panels (2) and frame (3)-

Inventors: BECQUART IGNACE, BECQUART, IGNACE
Applicants: BECQUART IGNACE, LIKASTAR INTERNAT CORP S A, BECQUART, IGNACE, LIKASTAR INTERNATIONAL CORPORATION S.A.
Application year: 2000
Main classification: E04B1
IPC codes: E04B1