NZ241471A - Method comprising moulding insulated panels with cavities, enclosing structural members therein when assembling a structure; lining and cladding the structure with reinforced polymer impregnated cement coating and including overlapping reinforcing mesh over adjacent panels - Google Patents

Description

241471 Priority is requested in respect to N.Z. Provisional Specification No. 241471 Date: 30 January i992 PATENTS ACT CCMPLETE SPECIFICATION AN IMPROVED METHOD OF USING INSULATING FCRMWCRK IN CONCRETE AND SIMILAR CAST STRUCTURES WE, CARLIN JOHN RUTHERFCRD, and JOIN GCRDCN RUTHERFORD, both of 2 Crest Lane Christchurch 8 New Zealand, both New Zealand citizens, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to the casting of foamed plastics resins such as polyurethane or polystyrene, into panels for use in the construction industry, with particular reference to the insulating and formwork properties of such materials when used in large wall sections whereby the foam plastics are utilised as a wall, ceiling, floor or similar surface for the interior and exterior of domestic, commercial or industrial buildings and the said plastics panels become an integral part of the structuisa—- -which can take several different' forms as descrilp^d^ ^ q hereunder. ^ ' V 1 * 12 JAN 1994 * 241471 It is a feature of the invention, that the foamed plastic panels arc in substantial sheets of, for example, half or full wall height, or on floors, or roof/ceilings in large panels. Such sheets relate to room sizes both in respect to height and length rather than using a multiplicity of small plastic pieces as has become one of the uses of foam polystyrene and similar materials in a hollow block form whereby such hollow blocks arc stacked up in varying sizes and styles and subsequently the cavities filled with concrcte or similar material suitable for use in a structure to support roofs in other load bearing or non load bearing circumstances. The disadvantage in the existing art in respect to the use of the small blocks, is a multiplicity of joins which can lead to cracks becoming noticeable on wall surfaces if any coating material designed to hide those cracks becomes cracked by movement of the wall, dampness, or for any other reason.

An unsatisfactory aspect of the method referred to above of using foam plastic .blocks stacked to make a wall and either collcctivcly "or individually filled with concrete, reinforcing steel and other necessary materials to construct a load bearing or non load bearing wall, is the tendency for the concrete, as it is being poured in, particularly as the wall increases in height, to place stresses on the foam blocks, leading to spillage of the concrete through rupture of the foam which acts as the formwork for the filling of the blocks with the structural concrete. There is also the potential for cavities not to be completely , filled with the concrete especially where these are horizontal cavities, and a number of blocks are being filled at the one time. A further disadvantage of this system is that the amount • of concrete required to fill the blocks and permanently join them together to make interior and exterior surfaces on walls that can later be surfaced with the desired materials for the finished cffcct, is the cost of the concrete and reinforcing steel, because more is used than would be required if a structure of concrete and steel .materials was designed with a view to minimising the use of the structural materials to the point where only sufficient are used to give the structural strength required to support a roof or upper floor or similar.

There is another undesirable aspect to the above described block form of building construction in that because the foam plastics blocks are light and may become blown over by wind or otherwise collapse under quite low forces, the wall thickness must be substantially greater (particularly when taking into account the coating of the wall ultimately with exterior and interior cladding materials) than would be conventional if a timber frame or other light steel or timber construction was used and the extra wall thickness increases the size of the building without increasing the space within the building. Accordingly this form of construction does not make such economic use of building sites, as thinner wall constructions.

It is the purpose of the present invention to improve upon the above described method of filling concrete into the cavities of foamed plastics blocks, in a manner that reduces the *"1'L 12 JAN 1994 n thickness, increases the size of the foam plastics wall sections significantly to (for example) half or full wall height. Accordingly, there is an increase in the speed of production of the foamed plastics wall sections and a reduction in the time of erection on site, by using more lightweight steel than concrete to minimise the thickness of the walls and roof panels and include only as much in the way of structural materials as is appropriate to the structure being created.

While the larger wall sections can be filled with reinforced concrete by the formation in the foam panels, of cavities that will be predominantly vertical in the wall, and spaced at intervals approximating the spacing of conventional timber, steel or similar studs or frames, a preferred method is to utilise light steel channel or similar section, preferably rolled from galvanised iron in the style used in galvanised iron roofing, so that preformed holes reaching from floor to ceiling in foam plastics wall sections will quickly and easily be filled by the studs that are wall height and dropped into the preformed holes and fixed to the floor and at the top of the wall by casting the same into the concrete floor and into a concrete beam at the top of the wall within chases formed at top and bottom of the foam panels. Alternatively such steel studs can be fixed into a steel channel or similar section at the top, to act as a top plate, and at the bottom (to act as a bottom plate fixed to the floor) and thereby form the basis of the wall prior to coating the interior and exterior of the walls in the manner described hereunder.

Timber studs can be used as a frame in similar manner but the inert quality of steel is more appropriate to the inert foam panels that form the backings for the claddings that provide the finished walls.

Panels used for ceilings, roofs, or combined ceiling-roofs, can be constructed in similar style with steel, timber or composite rafters or purlins inserted in cavities to span from (for example) a roof ridge to an outer wall. Surfacing roof panels to create a waterproof finish can be the use of galvanised iron, aluminium or composite sheets which when also used on the other (underside) of the panel can form a sandwich panel with structural capability to be self supporting without the internal rafters, and the ability to gain structural strength from an outside skin and/or internal light steel or similar members is a significant part of the invention as such flexibility in obtaining the desired structural result enables the designer of the building to minimise the cost.

The use of the same foam material on both walls and ceilings, and ceiling-roofs, especially with a cementitious coating as described hereunder, enables the continuity of the coating up walls and over ceilings and roofs in a manner that expedites construction, helps waterproofing and enhances structural integrity.

If by wav of example. the preformed holes in the foam polystyrene---v..

T 4 G 3 • O 12 JAN 1994 r 241471 or similar foam plastics walls are vertical holes spaced 600mm (2 feet) apart, the steel or similar wall studs (of cross section 75nun by 37mm - 3 inches by 1.5 inches for example) placed in these holes are fixed to the floor and the ceiling but such will not have the lateral bracing that may be required to meet earthquake or cyclone codes and it is a part of the invention that lateral stresses will be met by coating the said foam panels with a cementitious material that would conventionally have a reinforcing mesh on the exterior of a wall and on appropriate parts of the interior of each wall, such as corners of buildings (where there would be additional wrap around mesh fixed on site) to give a sandwich panel effect and structural strength to those panels requiring additional bracing and support to cope with lateral stresses and loadings.

Similarly, instead of studs as described above for walls, purlins or rafters are inserted in the preformed holes and later the cementitious coatings with appropriate reinforcing mesh can overlap and form a continuous skin on roofs and ceilings (and where appropriate, continuous with walls) to enhance the bracing and general structural strength of the building by giving three dimensional structural integrity and bracing by room sized, box shapes integral also with floors which can be fabricated in a similar manner, especially where floors are above ground level on sloping sites or serving second storeys.

An additional aspect of the invention is the use of the foam plastics sheets in sandwich panel form between 2 sheets of galvanised iron or similar waterproof cladding as roofing panels on top of the wall panels described herein with the thickness of such panels being related to the span required between vertical supports. Typically such span would be from the ridge in a roof to the outer wall of a conventionally sized house, or small commercial building, with a guttering attached to the lower edge to dispose of storm water. In such case, galvanised flat iron, aluminium or similar would be bonded to the underside of the roof panel to form the ceiling in the room below and the outer surface covering would be one of the conventional profiles of long run galvanised, aluminium or composite roofing joined at each panel edge with appropriate overlap to prevent leaking at the joints. Conventional ridging materials would be used on the ridges where the panels join at the ends, and the method of fixing to the walls below can be screwing, bolting or similar fixings appropriate to avoid the panels being dislodged by the stresses to which roofs are subject.

The gauge of the roofing iron, aluminium, plastics or other composite sheet material, is that used on other roofing systems but such can generally be lighter than otherwise because of the continuous backing support provided by the foam plastics sheet which will usually be of higher density and with less cavities formed for services than the wall panels described herein, so that the rigidity of these roof panels and their thermal insulating capability, makes this form of construction rapid, labour saving, and of high insulating value.

A u 12 JAN 1994 1X11 \ The type of bonding of the outer cladding of these roof panels is that generally available as contact bond adhesive or similar bonding agents used in the building industry, and the adhesive is relevant to the strength of the roof panel, as is the thickness of the foam, and generally the panels can be designed to have long or short span with varying insulation and structural qualities as required. The end result on the building is a lightweight well insulated roof which on the ceiling side can be textured or otherwise coated if preferred, to soften the appearance of the aluminium or galvanized iron which is the conventional surfacing material although other sheet materials can be used as required, with some loss of strength applicable if the material does not have the structural capabilities of conventional roofing iron.

While it is usual to have these roof panels sloping from a ridge to the outer walls or similar for draining water from the roof it is possible to use long run flat sheets to provide a horizontal surface for the ceilings provided there is an appropriate waterproofing membrane at edges or gutterings that prevents water from ponding on the roofs and rising to a level that permits leaks through the overlapping joints. Conventional practices for waterproofing roofs with flat or low pitch can be applied.

Cables for wiring can be run down the interior joints or otherwise covered by a textured coating if fixed to the underside surface of the combined ceiling and roof panels. Battons, beams and other decorative effects can be added as required without adversely affecting the structure, or general fixing methods described above.

An alternative to the use of galvanised iron or aluminium cladding on one or both sides of the above described roof and ceiling panels is the casting of waterproof cementitious material on one or both sides utilising the mesh referred to above as used on the wall panels with appropriate waterproofing additive to the cementitious coating particularly the addition of silicones, polymers, and other compounds such as chopped fibreglass sprayed on with resins, bituminous, butyl or similar membranes and generally once a sandwich panel construction has been developed by such reinforced coatings applied to the foam core, a variety of waterproof surfacing materials, both in large sections or strips or tiles can be applied as a decorative and waterproofing effect to the panels once appropriate rigidity, flexural and impact strengths are achieved by the use of reinforcing meshes and cementitious coatings on both interior and exterior surfaces to provide a resilient board that can be supported by beams or rafters, trusses and the like, or in some cases the support of load bearing partitions at appropriate intervals to give the structural strength required for a roof and ceiling system of this type. Engineering calculations as to the amount of mesh and the cementitious and similar coatings required to create the structural strength of the foam sandwich panels can be calculated by structural engineers in the conventional manner taking into account the capabilities of the individual and collective- v.^ 24U71 materials.

A significant aspect of the invention is that instead of using bolts, screws, adhesives and the like, where reinforcing mesh of the fibreglass, polypropylene or other plastics or similar meshes are the reinforcing medium used, such meshes can be applied after the sheets have been placed in position at ridges, corners, valleys, edges and the like and folded around corners and from roof panels to wall panels, to provide appropriate ridging, joining, waterproofing, structural and similar capabilities. Alternatively where expansion joints are considered appropriate strips of butyl rubber or similar are applied to joins with appropriate laps by the use of contact bond or similar adhesives to allow expansion joints where appropriate (generally every 10 square metres - 100 square feet or thereabouts) so as to avoid cracking. Flexible caulking materials applied by gun, tube or trowel are an alternative at expansion joints. If cracking at any ridges or joints should occur the same can be rectified by subsequent application of butynol rubber or similar flexible jointing strips or with caulking. Surface coatings of a flexible style in such instance can be sprayed or painted on to give continuity of appearance despite differences in the surface and jointing materials if concrete or other cementitious reinforced coating is used on the roof panels and a dissimilar flexible joiner strip is used at the joints.

It is a feature of the use of the lightweight foam plastics sheets as described above for wall and roof-ceiling panels that the panelised units can be fabricated as "bents" or combined wall and roof sections that, for example comprise a wall and roof section up to a ridge on the roof, with a matching piece forming the other side of the roof and wall so that the two sections when placed together form a freestanding roof and two walls. In such circumstances the steel studs can extend into the roof as purlins or rafters and these large sections are sufficiently light to be manhandled rather than placed with cranes and heavy machinery.

As such they are ideal for use in underdeveloped countries and remote areas to form integral box or similar room sized or larger enclosures that are easy to erect, have the capability as box sections to withstand earthquake or cyclone conditions and are impervious to attack by termites and other infestation.

There is a well established practice of using reinforcing mesh of a fibrous nature in association with cementitious coatings particularly fibreglass mats and meshes but the incompatibility of glass fibres in an alkaline environment provided by the cement in such mixes, makes the bond between the glass fibres and the cement, doubtful in terms of longevity. More recently inert plastics meshes made of polypropylene or similar resins, have been used especially in fibrillated form, to improve the adhesion to the reinforcing material and any substrate. Such adhesion is also enhanced by the use of polymers such as polyethyl acrylate added to the cementitious coating for making thin layers appropriate to the exterior of buildings which can be either, sprayed or trowelled on and applied in various textured forlfi^Jc.N 7" ^ * 6 1 ^ 12 JAN 1994 ' 241471 There are a variety of appropriate polymers, some of which are proprietary blends and polymer latex predominates. Particularly effective are styrene butadiene and acrylic latex.

It is an aspect of the present invention that such plastics meshes can be used in association with the polymers in the cementitious coatings to provide a well reinforced surface on both sides of structural walls to resist lateral forces that may be applied by cyclones, earthquakes and extreme wind loadings so as to make a sandwich panel where the outer surfaces of both sides of the foam panels with the steel supports as described above, are given bracing capable of withstanding any additional loads that might not otherwise be coped with by the steel and concrete aspects of the structure as previously described.

It has been found that gypsum plaster when used in association with plastics meshes is given additional impact resistance on interior walls and can be applied as a thin coat either sprayed or trowelled on and thereafter painted or wallpapered in the traditional manner appropriate for the interior of domestic or commercial premises.

Where additional impact resistance and flexural strength is desirable, especially on exterior walls, such can be obtained by using more than one layer of the above described plastics reinforcing mesh and progressively building up the cementitious coating with several layers of mesh, particularly layers of mesh (impregnated in layers of the cementitious material) wrapped around the corners of buildings where additional structural strength is appropriate to resist lateral forces that may be applied to the building by wind, earthquake and the like. Where such additional mesh layers are also used on the interior of such panels to give a sandwich panel effect, particularly strong panels can be created to provide the bracing elements appropriate to buildings that have extensive windows or similar less resistant elements to lateral forces.

The use of multiple layers of the said mesh embedded in the cementious materials with the addition of a polymer is particularly suitable where additional structural strength is required above windows and door openings where it is not appropriate to have the conventional steel studs referred to above and where in similar timber or steel buildings either steel or timber lateral beams would be used to support roof or upper floors above windows and doors. Such mesh can be used to surround beam-like pieces of the foam plastics to fill spaces above windows to ceiling height and the structural strength of such beams can be built up to the desired capability by adding additional layers of mesh and further polymer concrete to make a well reinforced cementitious coating that will have a structural strength at least equivalent to the more traditional timber or steel beams and such can either be applied in place in the building or alternatively cast into moulds in a factory and taken to the site for inclusion in the structure. If such beams are built up in situ, there is less handling and cost than for '^ £'' r / c 7 v"" 12JAN 1904 ' \>0 E 1 "J 24147 example, using a heavy RSJ or similar steel beam.

Casting of interior or exterior surfaces on the large foamed plastics sheets of any size up to wall height and room length or longer, for walls and ceiling/roofs can also be achieved in a factory situation, particularly where a high quality smooth interior surface is required to give a surface that would imitate the smooth surface achieved by gypsum plaster when cast into the material known as fibrous plaster or otherwise vised as "drywall" in interior cladding sheets which are conventionally attached to timber or steel framework to provide partitions in buildings.

Because the large wall and roof/ceiling sections are light, and the mesh referred to above can be incorporated in a cementitious coating that is cast onto the foam plastics, either by spraying the product into a mould and placing the foam plastics sheet on top of it or otherwise applying the coating on top of the sheet of foam, the end result is a light insulating sheet with a thin, yet reinforced coating, which is taken to the construction site where the exterior coating is conventionally applied after the building has had the exterior wall (and where appropriate roof/ceiling) panels positioned, with additional beams over windows and doors as referred to above, and a final coating, either textured or otherwise, finished in form suitable to providing a weatherproof finish, is applied.

It is another feature of the invention, that the cementitious polymer based cement and mesh, can be cast qnto the foam plastics with the use of moulds that have a mouldliner comprised of a flexible plastics material particularly the type of material as used in upholstery and similar applications that has "two way" or "three way" stretch. Such flexible material when used as a mouldliner in association with the polymer based cement will follow any minor shrinkage caused as the product sets and dries and such flexible liner can be peeled off to give an exceptionally fine finish that can either be smooth, or patterned to follow the pattern of the plastics mould liner to give an effect imitating tiling, leather grain, or similar finish that would duplicate markings on the mouldliner.

With regard to non loadbearing internal partitions, it is possible to cast the surface referred to above, onto both sides of a thinner plastics foam panel, than that used for the exterior of the buildings, as has been described above. Such panels when utilised in association with the mesh referred to above, have adequate impact resistance in the form of lightweight panels that can be produced in large sizes of full room height and of width that will span the distance conventionally found in room sizes in domestic and commercial buildings that are related to conventional living room and office sizes. Joins are minimized and the pieces can be cast to accommodate the dimensions required for each individual structure by blocking off parts of larger moulds and casting the surfaces of the foam panels which are made to a thickness of 50mm (2 inches) or thereabouts, depending on the degree of insulation and noise absorption required. In this^-;^ regard, because the casting of the cementitious coating onf'^lfe^ a 7 A 8 /• . mlj a 12 JAM 1994 4147 mould liner, as described above, gives a smooth and fine finish similar to gypsum plaster, but with greater density and structural strength, the relatively thin partition walls described above, have good noise absorption qualities. The use of more layers of the plastics mesh in association with the cementitious material and without the steel or concrete stud supports, can, where appropriate channels are used top and bottom, enable these panels to play a loadbearing role, particularly in the interior of buildings where roof panels are also made of foam in accordance with the description set out here under, as such foam panels, which can form both the ceiling and the outer surface of the roof, are relatively lightweight and can be made in similar manner to that described above, with the application of a waterproof membrane on the exterior of the foam panel sheets which are also made in large sections and can have the mesh and cementitious inner surface that forms a ceiling, stippled or otherwise textured to give a ceiling that does not display any joins, whilst the outside of the roof/ceiling panel can be either a galvanized iron, aluminium, or other waterproof cladding such as a butyl menbrane, or other slate, tiled or similar surfaces that can be attached to the foam by various adhesives, or by the use of screws, mesh, and cementitious coatings applied to the exterior as well as the interior.

Appropriate* waterproof joins, achieved by metal flashings, caulking, mastacs or other components, can achieve the necessary waterproofing between joins of the plastics and cementitious coated panels. The exterior coatings on the exterior of such roof panels can be flashed in a similar manner. An alternative to the use of the foam panel roof and ceiling system as described above is the use of the same panel with preformed cavities, through which are placed steel purlins which are made in similar style to the wall studs referred to earlier for providing the necessary structural support in the walls for roof or upper floors in the building. Such steel purlins can span from the roof ridge of a domestic structure to the outer wall and the under side of the panels can provide the ceiling. The same sandwich panel effect as referred to above when the panels are used in walls, can give added impact and flexural strength to roof panels. Likewise the use of the steel frame throughout the preformed cavities in the large foam plastics panels on roof and ceilings can be coated with the polymer inclusive cementitious coating reinforced by a reinforcina mesh which would be conventionally of an inert plastics material, as earlier described.

It is further possible to utilise the same panels to form both the ceiling of a room and the floor of a second storey or to make substantial floor panels above a basement ,or under floor garage to form the floor of the living sections of a building, with such a flooring system being very appropriate on hill land where more costly concrete floors cast in situ, on shuttering or underfill, might otherwise be used.

Sufficient initial strength for transporting can be given to such floor panels by coating one side of the peine 1 in the factory in 9 4 j 1 the above manner with a cementitious mesh reinforced coating while the top surface of the floor can be sprayed or poured onto the foam and incorporate the steel studs that form the wall supports as referred to above and similarly such panels can become an integral part of the top section of the walls to provide the ceiling and/or upper floor or roof panels thereby making each room a structurally strong box that can be designed to withstand cyclone and earthquake stresses as related to the amount of cement, steel and reinforcing layers of mesh utilised and designed to comply with local building codes. Cn the top surface of floors constructed in this manner, steel reinforcing mesh is the preferred mesh in the cementitious coating.

Another aspect of the invention is the manufacture of the foam panels and the modification of existing plasticss presses for the forming of the foam sheets, particularly the cavities required for the insertion of the structural materials such as steel, timber, and concrete. Conventionally, equipment used for the forming of large foam slabs of expanded poystyrene beads have moulds that permit the entry of steam and have sufficient structural strength to cope with the expansion of the beads as they fuse together. Such a mould would generally be 1 to 1.5 metres high, 450mm to 600mm wide and 3 to 4metres long and the slabs the full size of the mould would later be sliced for use as thinner sheets in the building and similar industries. The present invention includes the fabrication of heat conducting formers ( for example, aluminium or steel) such as tapering tubes (to assist removal from the mould after forming the foam) which are inserted in the mould to enable the formation of cavities of the shape, size and direction required in the thick panels that are formed by the above method and later sliced to the required wall or roof/ceiling thickness.

Such formers can be held in the mould by top and bottom channels to form chases in the top and bottoms of the sheets created, to provide space for casting in concrete or placing other horizontal structural members that help tie panels linearly, or to wall, roof and floor. Parts of the mould can be blocked off to allow for windows and door openings in the sheets.

When other foam plastics such as foam poyurethane is the sheet material, boxes, with formers placed in the disired directions can be fabricated and the formers withdrawn after the foaming has taken place, or alternatively the formers can be left in place to make for ease of pouring in concrete down such formers which become permanent ducts to take the structural materials, cables, bracing members and the like.

An example of the use of this building system with the foam plastics integral formwork used as a basis for concrete and steel structures in association with polymer based cemititious coatings with plastics or similar fibrous reinforcing is now set out below.

A typical method of manufacturing foam polystyrene in large sizes 12 JAN 1994 • V ' i / is the filling of large moulds by prexpanded polystyrene beads which are then further expanded in moulds, generally of the size described above. The resulting foamed polystyrene slab is generally sliced with a hot wire or similar to give sheets of this material which are conventionally used for insulation in walls or for packaging purposes. With a view to utilising existing plant of this type which is in common use, the moulds are fitted with formers which will provide the cavities necessary to enable insertion of the steel studs, purlins or similar structural members.

In the interest of conserving polystyrene beads, other cavities, usually elliptical, are formed in in between the cavities that will hold the structural members, and such additional cavities which provide good insulation in the form of still air, when totally sealed between floor and ceiling, also assist in the provision of service facilities such as cables and pipes whilst they can also be appropriate for conducting warm or cold air from central heating and air conditioning systems.

Such formers can be placed in the above described moulds in a manner that will enable slices of wall sections of approximately 175mm (7 inches) to be sliced off the large slabs that are conventionally formed in such moulds so that 2 or more slices can be taken off the slab that comes out of each mould by cutting down through the parts of the slab that do not have preformed holes and thereby providing several large wall sections where in the case of a mould that is 1.2metres (4 foot) high, two of these wall sections will form room height in domestic or office construction. Such formers will be conventionally aluminum sheet or tubing fabricated to provide the desired shape and generally tapered for ease of withdrawal from the mould while the aluminum also helps the steam heating necessary to cure and expand the polystyrene beads. Channels can be formed on the top and the bottom of these wall sections if desired, to enable lateral reinforcing or the passage of horizontal pipes or cables and after the panels are formed it is possible to cut them to shape to allow for windows, doors and the like to suit any particular plan of building, while additional horizontal or vertical grooves may be cut in the surface of the finished panels to enable the placing of wires, cables and pipes which can later be covered by the cementitious coating, either reinforced or without reinforcing as referred to above.

In the present example, the slab as it comes from the mould, after having the preformers taken out to give a series of cavities, is sliced to a thickness of 175mm (7 inches) which will be the wall thickness on which the cementitious coating will be placed on the exterior and interior after the slab has been positioned with the aid of the steel studs which in the present example are roll formed in 20 gauge galvanized roofing steel to form a "C-section" and two of these panels are placed on top of each other with a horizontal channel top and bottom of each of the wall panels which is filled with a cement grout to provide top, middle and bottom ties to the steel studs and such fixes the 11 w 2 \ 12JM11994 ,0; 241471 studs to the floor (where steel starter rods have been cast into the concrete floor) and such provides a measure of lateral bracing, whilst the concrete with appropriate steel reinforcing bar around the top of the wall continues through similar panels around the whole of the structure and lateral beams formed from the same polystyrene provide the wall sections above doors and windows.

An alternative to the use of concrete grout at floor level, half way up the wall, and at the point where the wall joins the ceiling is to tie the vertical studs to the floor with a similar galvanised channel attached to the floor, (by concrete fasteners if the floor is concrete) and similar channels on top of the lower half height foam panel and on top of the second panel at the top of the wall. Such horizontal members can be attached to the vertical studs by screws, bolts, welding, crimping or similar fastenings in manner used in light steel framed buildings.

Over windows and door openings, foam pieces without preformed vertical cavities, but with horizontal chases along the top edges, are tied into the wall panels by a continuous top plate of steel channel as described above, or poured concrete with one or more longtitudinal reinforcing rods. Such beams, where load bearing in respect to supporting roof panels, are later coated with several layers of the reinforcing mesh described above and a thicker cementitious coating (on all sides) than that applied to the remainder of the exterior walls.

Window and door frames are attached to the steel studs by bolts or screws and any exterior gaps filled with the cementitious coating that covers the outer walls. Such coating has a plastics mesh reinforcing which is a double layer impregnated into the coating at corners of the building to give added bracing but on other exterior and interior surfaces of the exterior walls there is one layer of mesh, with the interior undercoat and mesh being cast on in the factory. Polypropylene or polyethylene meshes are preferred, with the holes in the mesh approximating 5mm (,2inch).

The roof panels in this example are foam panels with long run galvanised iron roofing profile spanning from ridge to outer walls, with guttering attached to lower outer edges. Such roof-ceiling panels are screwed through overlapping joints to the steel channels on the top of walls and partitions below. Ridging and flashings are conventional style for galvanised roofing. Mesh impregnated with the cementitious coating is wrapped around vertical and horizontal corners where possible.

A further • example of an application of the invention can be demonstrated by the use of foamed polyurethane as the plastics medium for making the foam slabs that are the basis of the wall and roof system.

Foam polyurethane, being formed by a chcmical reaction, requires less costly mould construction as the pressure is controllable in the chemical reaction and large pieces can be made by lay^ncj cylindrical or similar formers into a box with intei^Lbr 12 12 JAN 1394 "? ■•v ■ 24147t * dimensions the thickness, height and width of the desired wall scction with such formers being tapered if preferred to assist withdrawal. The cavities that can be formed in such moulds may be either vertical cavities suitable for talcing the studs, or angle cavities suitable for including angle bracing to enable the placing of steel rods or straps on an angle in the finished wall to avoid the need for making the sandwich panel construction with multiple layers of mesh as referred to above, to gain the necessary bracing strength to avoid damage to the wall by lateral forces such as might be applied by wind or earthquakes.

While foam polyurethane .is normally a more expensive foam it has advantages in that it can be formed into less costly moulds which in turn can be blanked off more easily to make irregular shapes suitable for accommodating windows and doors in the foam panels. In the present example, the mould is made of dimensions to form an individual wall thickness and not based on existing wider slabs that are subsequently sliced as in the example referred to above due to the fact that the conventional foam polystyrene block moulds are designed to make larger slabs which are sliced subsequent to the foaming process to make the desired sheet thickness. In the case of the use of polyurethane foam, due to the lower cost of moulds, absence of steam and other facilities needed to fuse polystyrene beads, more flexibility can be achieved by using a variety of moulds, including moulds to make corner sections that have better bracing elements than straight wall panels, and combined wall and cciling-roof sections that arc particularly suitable for quickly constructing small domestic buildings, garages, portable site offices and the like.

In other respects the cementitious coatings or gypsum plaster coating for internal coatings with or without the plastics meshes as referred to above, can equally be applied to polyurethane foam slabs which have similar insulating properties to the foam polystyrene slabs. Similarly the same steel studs can be used in the vertical cavities and provision can more easily be made, due to the ability to vary the moulds by placing horizontal formers for ducting for cables or pipes. Similarly channels can be formed at the top and bottom of the wall sections to enable the steel studs to be cast into concrete beams around the top and bottom with the latter being appropriate for attaching the steel studs to steel "starter" rods cast into the floor slabs where such are used.

As with the foam polystyrene example earlier given, the foam polyurethane can have surfaces either cast onto it, or trowelled or sprayed on, or alternative cladding such as conventional masonry, planking, or other traditional surfacing can be used with adhesives. Blocks or bricks can be JLndepcndantly stacked up around the foam wall construction.

A further variation is given by way of example whereby cavities either formed in the polyurethane or polystyrene or similar plastics are filled with concrete similar to the style of--^y~';: construction used with foam polystyrene blocks filled with ^ o «o\\ O: 13 • ' t2-'.w!i394 241 concrcte and reinforced with steel but with the exception that full wall sized panels can be used and the concrete is predominantly cast into columns but with intermediate lateral bracing at half wall height or alternatively with some concrcte cast on an angle to form the bracing, but substantially less concrcte is used than would be employed in the foamed block formwork method earlier described as existing art.

It is also possible in the casting of the polyurethane panels, to cast in formers into a mould, which as described above, can conventionally be a shallow box with such formers being removed during the pouring process of the concrete, as if they are of plastics or other smooth surface they will aid the flow of the concrete into the wall sections once they are erected. By this method finger vibrators can be used and a drier mix of sand, cement, (and polymer if desired) to achieve greater early strength in the concrete. It is also possible to leave the formers permanently in the wall section to strengthen the wall to prevent rupture while the concrete is being poured which can be a problem with pouring concrete into the polystyrene blocks referred to earlier.

It is one feature of the invention when used in this manner that the concrete columns that are poured can be reinforced with a spiral wire or rod formed into a springlike shape which is lowered into circular or similar cavities and better provides reinforcing for columns than a straight rod centrally placed in the cavities intended for the concrete as is conventional in the polystrene block system. A substantially lesser amount of steel can be used if spiral wire or rod is used in addition to angle bracing in the form of steel rods or straps which are also cast into the concrete columns as they pass through such columns on the diagonal to provide better bracing at lower cost through less concrete, than the polystyrene block filling method.

Formers may be introduced to moulds and left in the foam plastics wall and ceiling or roof panels on completion of the casting process, to produce corners, beams that will be used in ceilings, or over windows and doors, and other variations in the shape of the wall sections that would otherwise be difficult to create in conventional moulds that are already in use for foaming polystyrene and which make a large slab that can be sliced into thinner slices but otherwise cannot easily be varied. When using the polyurethane foam, a significant part of the invention is the ability to cast in pipes in the wall, floor, ceiling or roof sections that can subsequently be coupled up for heating or water and in such cases can be appropriately insulated by the use of the foam in close proximity to such pipes thereby giving energy savings while electrical and communications cables can equally be placed in ducts cast in the polyurethane in a manner suitable to the plan of the building and such are thereby well protected from attack by rodents or other vermin.

It is possible to foam the polyurethane between galvanised- iiron, 14 wV aluminum, or other composite sheets by blocking off the edges of two such sheets and casting in the desired ducts and using the said sheets as permanent formwork which also becomes the finished or semi finished wall surfaces which may later be painted, wall papered or textured. By this method a conventional mould is not necessary and only edge sealing is needed to insure the foam is confined during the foaming process.

The accompanying drawing, Figure 1, shows the style of formers that might be used as removable formers in a typical foam polystyrene block mould where the dimensions of the interior of the mould, and the resulting foam block are typically 1.2 metres high, 450 mm wide and 3.7 metres or 4.8 metres long (4 feet by 1.5 feet by 12 or 16 feet long). The round pipes 1., would preferably be slightly tapered to enable ease of withdrawal and they are located in a channel 2., which helps position them in the block mould and such channel forms a chase in the bottom and top of the finished foam wall section, which enables linear ties of concrete, steel channel or similar to tie the panels to each other and to adjoining floor and ceiling/roof sections. The round pipes, (typically of aluminum and sometimes perforated to allow the entry of steam) form the cavities that accommodate the structural steel, timber, concrete or similar studs, joists, purlins, rafters and the like, as above described. The elliptical shapes 3., are removable tapered pieces of sheet aluminum or similar that form voids in the finished wall sections that conserve the polystyrene beads and can be used as ducts for services. In figure 1 the formers are intended to form cavities in a foam block that will be subsequently sliced linearly to give two wall panels of half the width of the block, but wider block moulds could have the formers of different dimensions, shapes and spacing to give thinner or thicker wall sections with more or less cavities depending on the finished strength required.

I y, 1rO/

Claims (26)

16. 4 7 j

1. A method of building a structure including the steps of: moulding a plurality of panels of large dimension and of foam plastics material in a reusable mould including forming cavities in the panels to take structural members or services; locating the plurality of panels adjoining each other to form a floor, walls, ceiling and/or roof which together constitute an insulating substrate; applying interior finishing linings and exterior cladding over both sides of the panels, the exterior cladding of exterior walls and the roof being a reinforced polymer impregnated cementitious or similar impervious coating to provide resistance to impact, abrasion, wind loadings and lateral stresses, to act as bracing and also act as a finished weatherproof surface, such interior finishing linings or exterior cladding, in respect to at least one of the substrate surfaces, being applied after placing such substrate in its permanent position in the structure and overlapping the adjoining panels with reinforcing mesh and the coating material; and including retaining the panels in position with structural members enclosed in the preformed cavities. 24 j What we claim is:

2. A building method as claimed in claim 1 including heating and thereby expanding the foam plastics material which comprises polystyrene beads or other plastics resin.

3. A building method as claimed in claim 1 including foaming the plastics material which comprises polyurethane or similar by chemical reaction.

4. A building method as claimed in claim 1 including moulding the panels which are to be located as wall panels at intervals, with vertical cavities shaped to fit the cross section of timber studs or of steel studs which subsequently provide vertical load bearing capability.

5. A building method as claimed in claim 1 including moulding the panels with cavities and/or edge chases in the foam plastics material and filling the cavities and/or chases with concrete and steel to provide enhanced structural and joint strength.

6. A building method as claimed in claim 1 including subsequently inserting ducts and cables for services in the cavities in the panels.

7. A building method as claimed in claim 1 including casting permanent pipes and ducts into the foam plastics panels to carry services such as water, gas, electricity, communications, and the like, and joining them to matching pipes and ducts in adjoining panels.

8. A building method as claimed in claim 5, including filling the chases along the edges of the panels with cement and steel or timber to form a structural tie along the top of a wal,l^fjw|i^^ the panels are of full wall height, or at half wall h^Lght ?«Jr\ ■'& ' !^,9a ; >S94 24 i ' 17 ^ \ ^ 7 \ half height panels) to give structural Integrity to the walls, and to join the panels, whether the same be used for walls, floors, ceilings or roofs.

9. A building method as claimed in claim 1 including applying mesh reinforcing to the exterior cladding and the interior lining which include a cementitious material and applying the cementitious material in a thin coat or coats for structural purposes with or without applying subsequent coats of waterproofing, texturing or colouring material, the mesh comprising any one of polypropylene resin, polyethylene or its derivatives, glass fibres, steel rod or expanded steel perforated sheet.

10. A building method as claimed in claim 1 or claim 9 including mixing a polymer with the cementitious material to improve the adhesion and structural strength of the said coating or coatings.

11. A building method as claimed in claim 1 including roll forming steel sections that comprise the structural members in the walls from roofing gauge galvanized iron into appropriate structural cross sections.

12. A building method as claimed in claim 11 including joining the roll formed galvanized iron sections which comprise C-section or channels and which are located as both vertical and horizontal members in the structure, with appropriate fasteners to provide a framework.

13. A building method as claimed in claim 9, including layering the cementitious exterior cladding or interior lining of the wall and roof panels and applying the mesh in several layers interspersed with the cementitious material to give greater structural strength.

14. A building method as claimed in claim 9, including layering the reinforcing mesh in several layers and with differing plastics, glass, or steel components, to add to the structural strength.

15. A building method as claimed in claim 1 including sandwiching the foam plastics panels between reinforced coatings to give an increase in the structural capability.

16. A building method as claimed in claim 1 including fabricating wall and ceiling roof panels as one piece in the form of "bents"; matching and joining the bents with mirror image bents to form standalone modules with two walls and a roof section; and waterproofing the ridge and other intermediate roof joints with a membrane or similar ridging material.

17. A building method as claimed in claim 9 including ^x^pping the reinforcing mesh included in the cementitious coajti^sT^j^o^ind corners or lapping it over wall, roof and ceiling-^joints 'Co improve waterproofing and structural strength. ^\\ ' f? )* t / p" D;24;la;71;

18. A building method as claimed In claim 1 Including moulding additional cavities in the foam plastics panels additional to those required for insertion of the structural members, or services, to reduce the quantity of the foam plastics resin and lower the cost of the panels.;

19. A building method as claimed in claim 1 including removing formers defining cavities in the foam panels from the moulds which comprise expanded polystyrene moulds or presses.;

20. A building method as claimed in any of the preceding claims whereby the interior finishing linings and exterior cladding are cementitious coatings; spraying or casting against a mould liner at least one such coating; applying the foam plastics thereon and subsequently removing such liner which is a plastic membrane (supported or unsupported with a stretch backing cloth) of the two way or three way stretch variety (such as vinyl or polyurethane, as used in upholstery and similar applications) which will follow any surface movement as the coating sets, and thereby duplicate the surface of the liner, which may be patterned or plain, on one or both visible surfaces of the panel, thus making a pre-coated panel.;

21. A building method as claimed in claim 20, including colouring the cementitious coating with pigments or other colouring materials to give a cast decorative surface that imitates polished stone, tiles, bricks, wood grain, or similar.;

22. A building method as claimed in claim 20 or 21, including adding finely ground material such as pozzalans, or calcium carbonate to the cementitious coating to assist in producing a fine and grain free surface to better reproduce the surface of the mould liner.;

23. A building method as claimed in any one of the preceding claims including inserting studs, floor joists, ceiling joists and/or roof rafters in the respective panel cavities.;

24. A building method as claimed in the preceding claim including coating both sides of floor, ceiling, roof, or ceiling-roof panels with the reinforced cementitious coating referred to in the previous claims, so as to form a sandwich panel with structural and/or waterproofing capabilities.;

25. A building method substantially as claimed in any one of the preceding claims and with reference to the accompanying drawing.;

26. A building structure substantially constructed by any of the building methods claimed in any one of the preceding claims and with referen^|^£o the accompanying drawing.;J&. ■ OV;f 12 AUG 1994;* tPA