WO2008004896A2

WO2008004896A2 - Building system

Info

Publication number: WO2008004896A2
Application number: PCT/NZ2007/000168
Authority: WO
Inventors: Daniel John Glew; Linton Albert Gemmell; Grant Kenneth Syminton; Trevor Jack Swinburne
Original assignee: Rapid Rooms Limited
Priority date: 2006-07-04
Filing date: 2007-07-02
Publication date: 2008-01-10
Also published as: WO2008004896A3; NZ548289A

Abstract

This invention relates to a building system. Particularly, although not exclusively, the present invention relates to a method of construction for a building such as prefabricated sections for building as shown in Figure 1. These sections could be the fittings of a house, hotel room, bathroom module, floor panels, roof sections, or wall sections, or other building elements. There is provided a method of forming a prefabricated building panel characterised by the steps of: forming a mould frame that defines the perimeter of the building panel; attaching reinforcement structures to the frame such that the structures sit within the panel perimeter; adding filling material to the mould frame; and allowing the filling material to set within the mould frame to form an integral building panel which includes components of the mould frame reinforcement structures and filling material.

Description

BUILDING SYSTEM

TECHNICAL FIELD

This invention relates to a building system.

Particularly, although not exclusively the present invention relates to a method of construction for a building such as prefabricated sections of a building. These sections could be the fittings of a house, hotel room, bathroom module, floor panels, roof sections, or wall sections, or other building elements.

BACKGROUND ART

There are numerous commercially available systems for the manufacture of prefabricated building elements.

Prefabricated building elements are commonly used in the construction industry. They are advantageous because they can be prepared off-site to predetermined dimensions. They are then able to be easily assembled on-site allowing quick and easy construction of buildings.

However, the methods of construction of these building elements varies depending on the nature of the elements and the building being constructed. The various building elements include floors, walls and roof sections which can be attached to support structures and/or each other.

US 4,221,441 discloses a prefabricated kitchen - bath utility system with kitchen elements (sink/stove) sharing a common wall and floor sections with a bathroom elements (sink/shower/toilet).

De Geest of Otaki, New Zealand for many years have manufactured prefabricated bathrooms for hotels and apartments with timber framing and interior walls of Hardie™ compressed sheet.

Philip Leather Builders Limited of Hamilton, New Zealand currently manufacture a large number of bathrooms for apartment buildings. These bathrooms are prefabricated with wood fibre product, tri-board™ or maxim-board™.

However, the disadvantages of the above technologies are they cannot form an inter-tenancy fire rating and do not have the structural integrity or load bearing capacity to support additional apartment units. Also, the prefabricated modules require a floor to be poured before they can be manoeuvred and positioned on the floor.

Rasselstein, a German company manufacture a wide range of prefabricated bathrooms in pre-cast concrete. In order to manufacture these pre-cast units, a mould is first made to form the three wall, floor and roof elements. They are all cast in one pour, the mould removed and then the elements assembled together to form a cube.

However, the tooling up costs of a removable mould are expensive and a number of different moulds may be required depending on the size of the building. Also, the panel thickness of these structures are greater than 75 mm which adds to the construction weight and requires a floor to be placed on an additional floor for structural integrity.

Therefore, the Rasselstein construction method requires three moulds, one for the floor, one for each side and a roof piece. They are joined post mould cure and are expensive to manufacture.

US 5,136,822 discloses a prefabricated building element manufactured in a variety of modules. All of the exterior modules have a surface design to be exposed to the outside environment and fabricated from exterior building materials typically used in the industry. The inside surface is also fabricated from interior building materials used in the industry.

Sheet metal top and bottom channel plates are based inside and outside the wall surfaces apart and the inner cavity is filled with insulating material. The lateral end of each building element is closed by a rectangular sheet metal interior support column which also functions as a means to connect each building element to the adjoining building element.

Each module has one interior support column. A sheet metal vertical attachment member midway along each building element provides additional means holding the wall elements of each module together.

However, the disadvantage of this invention is that the vertical attachment members do not provide structural support and therefore the required structural integrity to place additional units on top of each other.

US 5,070,661 discloses a prefabricated dwelling capable of being employed on a single dwelling unit or in a co-operative relationship with one or more like dwelling units. A dwelling unit has a body member provided with a wooden floor, a pair of corrugated side walls attached to the floor. There is a cover member attached to the side walls opposite the floor and a door at level one and at least one window located in the side walls, the corrugations of the side walls facing toward the interior of the dwelling unit and forming supporting and strengthening studs.

The dwelling unit may also be provided with electrical connections, cabinet units, a cooking unit and kitchen and bathroom plumbing units and associated amenities.

A plurality of the units can be stacked in a vertical disposition one on top of another and provided with an external stairway for access to each unit and units may be disposed in a horizontal, staggered relationship butting each other. However, the disadvantage of this invention is that it is provided with a wooden floor which does not form an inter-tenancy fire rating.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION

According to one aspect of the present invention there is provided a method of forming a prefabricated building panel characterised by the steps of:

a) forming a mould frame that defines the perimeter of the building panel;

b) attaching reinforcement structures to the frame such that the structures sit within the panel perimeter;

c) adding filling material to the mould frame; and

d) allowing the filling material to set within the mould frame to form an integral building panel which includes the components of the mould frame reinforcement structures and filling material.

According to another aspect of the present invention there is provided a prefabricated building panel formed by the method above.

According to another aspect of the present invention there is provided a building structure

characterised in that

the structure includes at least one building panel as described above.

Throughout the present specification the term 'prefabricated' should be understood to mean a prefabricated section of a building.

Throughout the present specification the term 'building panel' should be understood to mean a section of a wall, floor or roof of a building.

However, this should not be seen as a limitation on the embodiments envisaged for this invention. Other embodiments envisaged include footings of a building, or any aspect of a building.

The building panel provides the necessary structural integrity and a load bearing capabilities to vertically stack building structures on top of each other. For example, this stacking may be utilised in hotel, apartment rooms and any other such rooms. The structures are also able to be used inside various forms of engineered structures, including seismic structures.

In most cases the building panels are partitions in load bearing walls, floors and ceilings.

The structures for seismic and engineering requirements are also able to be met where the floor or roof is an inclusive part of the load bearing structure spanning between the grid beams. This eliminates the need for a separate concrete floor to be included in the structure.

In preferred embodiments the mould frame encases the filling material around at least the side of the perimeter. Covering the top and bottom of the mould frame may be optional. For example, the bottom of a door where a door brace may be installed.

Preferably, the mould perimeter is manufactured from DURAGAL ™ angle iron manufactured by Onesteel in Australia and distributed in New Zealand by Steel and Tube Holdings with dimensions of 120 mm x 75 mm x 6 mm. The dimensions of DURAGAL™ may vary dependant on size of module and related engineering requirements.

However, this should not be seen as a limitation on the present invention as other types of materials including angle iron, steel sheet, or composite material with any dimensions may conceivably be used with the invention.

The mould frame maintains tension to hold the filling material in place. In preferred embodiments the mould frame may be configured with an external securing device. Throughout the body of specification the term 'external securing device' should be understood to mean a device which connects the adjacent prefabricated panels together.

In preferred embodiments of the current invention a protrusion such as a lip from the DURAGAL™ angle iron forms the securing device.

However, this should not be seen as a limitation on the present invention. Other embodiments envisaged to connect the adjacent prefabricated panels include a tab, metal strap or any other such article of any other material.

In preferred embodiments of the present invention the lips of a securing device on the building panels are welded together to form a building structure.

However, this should not be seen as a limitation of the present invention as the lips may be bolted together or joined in some other way.

Throughout the specification the term 'reinforcement structure' should be understood to mean any article capable of providing strength and structural integrity to the building panel.

In preferred embodiments the reinforcement structures may include steel rods, bar and/or mesh.

The reinforcing rods maintain the structural integrity of the frame and take the load bearing to the floor level.

The reinforcing mesh may be joined to the mould frame to provide additional strength and purchase for the filing material.

The methods of joining may include welding, bolts or any other type of joining means. In preferred embodiments bolts are welded inside the frame for fitting lifting eyes for manoeuvring the panels once poured.

Throughout the present specification the term 'filling material' should be understood to mean any material capable of being inserted or poured within the mould frame to form a panel.

In preferred embodiments of the present invention the filling material is concrete.

However, this should not be seen as a limitation of the present invention. Other embodiments for the filling material include plastics material, plaster or other cementitous material.

The cementitous material is allowed to set such that the combination with the reinforcement structures and frame means that the panel is able to support its own weight when lifted.

In preferred embodiments the panels may include electrical conduit.

The present invention has a wide variety of uses as a building structure.

An object of this invention is to manufacture prefabricated concrete rooms that provide a fireproof and noise resistant structure that meets all structural code requirements, but can be stored outside during a long construction period without damage. Each room can incorporate a full floor, walls and roof, minimising the building structure requirements which only require a foundation, concrete beam or steel beam grid with a maximum 2.4 meter span between supporting beams.

Each room may be completely factory finished internally and externally incorporating all floor finishes, wall finishes, ceiling, plumbing installation, electrical installation and cabinetry and showers and fittings. All rooms can be stored outside and, once ready, can be transported to the construction site and craned into position.

Unlike other pre-built room manufacture currently available, this invention provides a fully engineered structure which may include a structural floor within the cubicle and a fully fire rated inter-tenancy wall construction which can be left in the open environment for long periods of time without damage.

Each unit can be fitted with full display windows, air conditioning unit and ducting and can also include furniture.

For example, the construction method can produce rooms up to 8 m x 5 m in precast concrete. Therefore, not only a prefabricated bathroom and kitchen can be produced, but an entire hotel room or hospital ward or any other such room.

The sizes of the modules can be varied significantly and it may be possible to make larger units with light weight concrete that meet standard engineering requirements.

In preferred embodiments the building structure may also be provided with at least one of the following: electrical connections, cabinet units, cooking units, kitchen and bathroom plumbing units and associated fuel lines, water lines and sewer lines, water taps, smoke alarms, sprinkler systems and other such amenities.

The walls can be lined with appropriate wall linings, floors tiled, etc and all of the cabinetry and fittings installed to a high factory finish standard.

A plurality of building structures may be stacked in a vertical disposition one on top of another or may be disposed in a horizontal, staggered relationship, abutting each other, or placed individually.

There are a number of advantages associated with this invention. The steel frame forms the mould so a separate mould is not required for the fabrication of panels.

This reduces costs and allows greater flexibility to manufacture different size panels. For example, building structures up to 8 m x 5 m can easily be produced that weigh less than 20 tonnes. Therefore, these structures can be lifted by standard tower cranes and can be fully pre-finished in a factory prior to lifting into a position.

Furthermore, from a financial perspective, the construction company will save a significant amount of build time (potentially up to 30%).

The method of forming a building panel allows site or adjacent to site build when individual walls and floors are poured separately as panels. This keeps freight costs down in remote locations.

The panels can be engineered to suit particular building engineering and seismic requirements.

The panels offer a complete water tight product and inter-tenancy fire protection ready for installation.

The panels have the necessary structural integrity and load bearing capacity where the floor is inclusive of the building structure spanning between the grid beams eliminating the need for a separate concrete floor to be included in the building. By using a steel frame constructed in a jig, a higher level of accuracy can be obtained. This floor may then serve as a roof of another structure when stacked upon each other to form an apartment.

Other specific advantages include:

• Designed to meet structural requirements • Fire rated

• Waterproof

• Includes floor

• Speed of construction • Eliminates pilfering

• Minimises down time

• Minimises on-site structural requirements

• Minimises separate trades needed on site

• Meets inter-tenancy fire rating requirements • Meets inter-tenancy acoustic requirements

• Flexibility in room sizes and shapes

• Eliminates concrete mould disassembly and storage

• Eliminates concrete mould cleaning

• Provides cost effective construction • Allows precise factory fitting of componentry and finishes to an extremely high standard.

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a diagrammatic representation of a side wall panel of one preferred embodiment of the present invention;

Figure 2 shows a diagrammatic representation of an end wall panel of one preferred embodiment of the present invention; Figure 3 shows a diagrammatic representation of a floor slab of one preferred embodiment of the present invention;

Figure 4 shows a diagrammatic representation of a floor plan of one preferred embodiment of the present invention; and

Figure 5 shows a diagrammatic representation of another floor plan of one preferred embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

With reference to the figures, there is provided a method of forming a building panel.

Figure 1 shows a 75 mm thick concrete side wall panel (1) where a galvanised lifting rod (2) is cast into the top edge of the walls and this is welded inside the wall panel to additional reinforcing steel rods which take the load down to floor level. Reinforcing mesh (3), type 663, 40 - 50 mm which covers all around is also welded between the frames and additional bolts are welded inside the frame for fitting lifting eyes (4) for manoeuvring the panels once poured.

The frame is manufactured out of 75 mm x 50 mm x 6 mm DURAGAL™ angle (5) for the top and sides and 125 mm x 75 mm DURAGAL™ angle (6) for the bottom. There is an inclusion of a door brace (7). Electrical conduit (8) completes the components of the side wall panel.

Once the frame is complete, the panel (1) is poured on a vibrating casting table or any other such method known in the industry could be used (e.g. a stable flat surface or other forms of vibration/product settlement) and screeded and trowelled smooth on the top surface which would normally be the internal wall. The steel frame (5, 6) forms the mould so a separate mould is not required for the fabrication of the panels.

Once poured and cured with high strength concrete which includes small aggregate, the panels are lifted by using the lifting eyes (4), positioned together and held with pipe clamps while the steel angles (5, 6) that form the outer frame of each panel are welded together.

Figure 2 shows a 75 mm thick concrete end wall panel (9) with similar construction manufactured out of 75 mm x 50 mm x 6 mm DURAGAL™ angle (5) for the top and sides and 125 mm x 75 mm DURAGAL™ angle (6) for the bottom.

Reinforcing mesh (3), type 663, 40 - 50 mm which covers all around with electrical conduit (8) completes components of the end wall panel.

Figure 3 shows a 100 mm thick concrete floor slab (10) with a similar construction manufactured out of 100 mm x 100 mm x 6 mm DURAGAL™ angle (11) all around.

Reinforcing mesh (3), type 663, 40 - 50 mm covers all around with a 25 mm fall shower tray (12) moulded into the floor slab (10) and shower waste outlet (13) completes the components of the floor slab.

The roof and ceiling are formed by making a frame out of light gauge purlin steel and fixing an 18 mm sheet of pre-finished tri-board™ (14, Figure 4) to the base of the frame then craning the roof frame into position over the room before bolting it into place in the pre-fixed bolt holes.

Once all the electrical and other conduits are fitted in the ceiling area additional steel RHS spreader bars are installed between the lifting points. A top sheet of 18 mm tri-board™ is fixed over the frame and overhangs the walls to form a temporary waterproof roof.

With the ceiling in place, all the walls are lined with appropriate linings, the floors are tiled and all the cabinetry and fittings are installed to a high factory finished Standard. In addition, the fire collars for all the plumbing penetrations are fitted so that the unit is ready for installation.

The size of the reinforcing mesh (3) shows that the floor of the unit is self supporting and can span up to 4 metres between grid beams.

As a result, these pre-cast concrete units can be placed straight on to grid beams without the need for a floor to be constructed. With additional reinforcing steel in the slabs, the units may also be able to be stacked up to 3 stories high without a structural frame being required.

Figures 4 and 5 show a typical floor plan of the proposed units manufactured by this method with internal beams (15) stub wall (16) and join between both units (17) shown.

For additional exemplification and clarification additional production methodology is outlined below:

Floors

The perimeter frame is manufactured from Duragal steel angle with dimensions of 100 x 100 x 6mm.

• It is ensured that all Duragal angle is pre-cut to required lengths and angles prior to delivery and pre-punched to accommodate lifting point holes and reinforcing bars.

• The set steel frames are set up in a preset square jig on a work bench. They are then clamped down to a heat sink surface to ensure straight edges and the corners and doorway portals are welded up. • Lifting eye nuts are welded on the inside face of the angle.

• Reinforcing bars are welded in at lifting points from the top to bottom of the frame.

• Reinforcing mesh is welded in line with specification tables, Figures 6 to 9.

• Lifting eyes are threaded in or greased grub screws inserted into any nuts to protect the threads.

• The frame is moved to the next table to fit with penetration liners, conduits and under floor heating cables.

• The casting bed is prepared with stops and magnetic blocks and machined plastic moulds installed onto the casting bed to form rebates as required for shower recesses or similar rebates.

• The frame is then placed onto a casting jig and clamped down onto the casting table and sealed around any potential leak points.

• Concrete is poured with the required strength.

• The prefabricated panel is left to cure on the heated casting table for 12 hours before removal from the table and positioning for assembly.

Walls

The perimeter frame is manufactured from Duragal steel angle with dimensions of 75 x 120 x 6mm.

• It is ensured that all Duragal angle is pre-cut to required lengths and angles prior to delivery and pre-punched to accommodate lifting point holes and reinforcing bars. • The set steel frames are set up in preset square jig on a work bench. They are then clamped down to a heat sink surface to ensure straight edges and the corners and doorway portals are welded up.

• Lifting eye nuts are welded on the inside face of the angle.

• Reinforcing bars are welded in at lifting points from the top to bottom of the frame as per Figure 1 and 2.

• Reinforcing mesh is welded.

• The frame is moved to the next table to fit with penetration liners, prefabricated electrical conduit and flush boxes, prefabricated Rehau plumbing pipes and connection recesses installed.

• The casting bed is prepared with stops and magnetic blocks and machined plastic moulds installed onto the casting bed to form rebates as required for decorative rebates into exterior walls (manufactured from plastic).

• The frame is then placed onto a casting Jig and clamped down onto the casting table and any potential leak points are sealed.

• Concrete is poured with required strength.

Internal Wall Fabrication An objective of this invention is to minimise the time spent on framing, fitting out, lining, stopping and painting preparation carried out inside the building as each of these processes has a time requirement that slows production. For this reason, internal walls are made with a 45mm thick timber or galvanised steel frame which is pre-made to the required size and fitted with all necessary wiring, conduits, flush boxes and plumbing pipes to meet design requirements.

The frame is full height but is 100mm shorter in length than the required wall.

Once fully fitted, the pre-painted 18mm tri-board or maxim board panels are glued and back fixed wherever possible to the frame. Once both surface panels are in place, any pre-hung doors, which will have the door jambs rebated to the overall wall thickness, can be slid onto the wall frame from the floor end and secured into position with fixing screws under the door stops. Steel or aluminium door jambs can also be used if required.

Once the door is in place, a stiffening bar should be fixed along the bottom edge of the wall to ensure it stays straight during installation.

Before installing into a structural shell, a 45mm x 45mm square guide is fixed at each end of the partition wall location and this will act to secure the wall in the correct location and guide it into position when it is craned in from above.

Once the concrete walls are all assembled, the internal partition is lifted by a gantry crane and dropped over the guides into position. Once in position, the stiffening plate across the bottom of the door can be removed before the wall is finally dropped to the floor.

It is envisaged that there will be a small gap in each wall junction which will either be covered by the wall lining material but, if a paint finish is required, it will need to be flushed off with filling compound, sanded back and touched up with paint to match the other wall. In an alternative embodiment, a small decorative corner facing may be utilised.

Internal Wall Assembly Detail

The construction of a dividing wall and assembly is fundamentally a kitset procedure. Panels, walls and componentry are fixed in sequence starting with the required quantities, followed by:

• A cutting schedule required for each component, multiplied by the number of forecasted jobs/units required.

• 50mm x 50mm galvanised box section affixed to the two vertical side concrete wall panels marked for example, with 'A' and 'B' with five 50 mm x 8 mm diameter screw bolts at a set distance from X to Y end walls. For example, an inside measure set from a bathroom wall at centre line of 1.885m.

• The construction of the wall is 18 mm tri-board. Studs are 53 mm wide x 36 mm thick. The tri-board studs are spaced at approximately 500mm centres. The tri-board is then glued and secured to studs with countersunk 8 gauge 1 1/2" 60 mm chipboard screws. There is one row of centrally positioned nogs mid-span.

• A pre-hung door and frame are set into bathroom/kitchen wall - refer to Figure 4 for dimensional lay out. The trim size height is 2.027 x 856. The door is 1,980 mm high MDF unclashed solid core door, 38 mm thick, hung on 30 mm rebated pine square jambs liners with a planted 30 mm x 10 mm door stop (re-run a standard run jamb for a 53 mm stud). This allows for 19 mm linings. • The pre-assembled door is carefully slipped over and fits between the 19 mm linings. This can be achieved if a flat working bed is used. The tri- board panels slide into the rebated door jambs. The jambs are secured with countersunk wood screws into studs.

• The pre-assembled wall and door is lifted as a complete unit up and over the walls and slotted down over the full length retaining lugs. A bottom plate is affixed to the concrete floor with two stainless steel R/A rebated brackets and secured with 5 mm diameter mushroom spikes.

• A pro-electrical fuse board is utilised and the light and power outlets are pre-wired. Also, pre-plumbing for a cistern and reticulated internal wall piping for WC position is allowed for at this stage.

• A privacy lock, stainless steel lever type is fitted on the door.

Ceiling Construction

The ceiling frame is manufactured with 100 mm galvanised steel 'C section light gauge purlin steel which is all pre-cut and pre-punched to required sizes and then bolted together using hug bolts and brackets.

If a negative detail is to be used, this frame should be primed and painted in the selected colour before glueing and secret fixing the pre-painted 18mm tri-board or maxim board which has been pre-cut to size onto the bottom side of the ceiling frame.

To create a negative detail, the tri-board or maxim board is cut 25 mm shorter than each edge leaving the painted steel frame exposed around the edge.

If the room is larger than 2.4 m x 3.6 m, the junction between the tri-board panels should be bridged with a full length aluminium recessed combination light box and air duct, product code CSDE 19 diffuser and integrated light filling from Holyoake Industries.

While on the work bench, this ceiling panel should also be fitted with all necessary light fittings, conduits, ducting, air conditioning units, sprinklers, audio requirements and insulation before being craned into position on the assembled concrete shell. Also, the ceiling panel is fixed through the pre-punched holes in the ceiling frame into the pre-welded nuts in the steel perimeter frame of the concrete panel where the grub screws have been removed.

Roof

If a separation is required between the ceiling frame and the roof frame to accommodate the air conditioning units or ducting, then a second steel frame will be required to support the roof constructed in the same manner as the ceiling frame.

Depending on the likelihood of the units being left in the external weather conditions and cost factors, the roof of each unit can be clad with building paper over the steel frame and then light gauged metal roofing which can be folded down around the edges to ensure weathering and can be flashed around the lifting bars that will penetrate the tops of the longest two walls.

Alternatively, pre-painted tri-board or maxim board sheets can be laid over the roof extending to the outside of the concrete walls to provide temporary weathering. If this method is used, it will be necessary to flash over any joins in the tri-board / maxim board roofing material to prevent weather penetration.

Either roof chosen will provide an ideal surface for any service personnel who arerequired to get into the narrow space between floors to install or repair and maintain plumbing and waste fittings from the structure above. Assembly of Units

Once the unit is assembled, all weld joints, both inside and outside the cubicle, need to be wire brushed and cleaned then primed with a suitable 2 pack metal primer.

After priming of all welded areas, all joints between the concrete panels need to be sealed, both inside and outside, with an acrylic sealant adhesive. Sika 11FC or similar is recommended.

Gaps between the partition wall and the concrete wall junction should also be sealed in a similar way. Gaps in the ceiling junctions should also be sealed with the appropriate coloured sealant.

Interior Wall Linings

The wall sub-strut should be prepared in accordance with the manufacturers specifications for the particular lining that has been selected for each wall then the wall cladding material should be fixed to the sub-strut in line with the product specifications.

Floor Linings

The floor sub-strut should be prepared in accordance with the manufacturers specifications for the particular lining that has been selected for each wall then the wall cladding material should be fixed to the sub-strut in line with the product specifications.

Shower Surrounds

Proprietary shower surrounds should then be fitted in accordance with the manufacturer's specifications. Cabinetry

All cabinetry should be installed in accordance with the manufacturer's specifications.

Plumbing Second Fix

Install all plumbing and waste fixtures to manufacturer's specifications. Connect all water supply and waste fittings to junction points. Install fire collars to all penetrations and make ready for on-site connections in accordance with best practice.

Electrical Second Fix

Before any roof cladding material is installed, use the draw wires previously installed to draw cables and terminate at the appropriate electrical enclosure. Where electrical cables are required to run through to additional pre-constructed buildings, use proprietary clip plugs or junctions boxes to terminate the cabling for easy connection on site.

Closure

Once all work has been fully completed, the unit should be tested for all operating functions then cleaned out thoroughly to new condition before the door is locked with a secure mortice lock with a factory only key, so that it cannot be opened again until handover on building completion.

Exterior Finish

Flush off any exterior junctions that will be visible on installation by first priming any exposed steel with an epoxy and then flushing off with an epoxy floor levelling compound such as Shield Patch or Epoxyflex. All exterior surfaces should be lightly sanded back and any imperfections rectified with a flushing compound such as Villastop.

Exterior Painting

Once the exterior of the unit is flushed off, it should be painted with a primer or sealer coat as a minimum to avoid moisture penetration.

Exterior Cladding

It will be visible once the building is complete that there can be a variety of finishes from simple acrylic paint through to:

• Metal cladding • Ceramic tiles

• Granite

• Weatherboards

• Glass

• Or any other decorative panel

All exterior surfaces should be installed to best practice using the manufacturers' specifications.

Transport

Using a 20 tonne gantry in the four lifting points on the tops of the walls of each unit, the unit, once completed, can be lifted from the bay and transported to the loading dock for shipment to site. Once on site, the unit room can be placed outside in a secure yard area until it is ready for lifting into position on the frame or foundations and concrete framed buildings should have steel plates cast into the beams that will allow the unit to be welded onto the beam plates. Where steel beams are used, the units can be welded directly to these. Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope of the appended claims.

Claims

WHAT WE CLAIM IS:

1. A method of forming a prefabricated building panel

characterised by the steps of:

a) forming a mould frame that defines the perimeter of the building panel;

c) adding filling material to the mould frame; and

2. A method of forming a prefabricated building panel as claimed in claim 1 , wherein the filling material is allowed to set such that the combination with the reinforcement structures and frame means that the panel is able to support its own weight when lifted.

3. A prefabricated building panel formed by the method as claimed in either claim 1 or claim 2.

4. A prefabricated building panel as claimed in claim 3, wherein the mould frame encases the filling material around at least the side of the perimeter.

5. A prefabricated building panel as claimed in claim 4, wherein the filling material covers the top and bottom of the mould frame.

6. A prefabricated building panel as claimed in any one of claims 3 to 5, wherein the mould frame perimeter is manufactured from angle iron with dimensions of 120 mm x 75 mm x 6 mm.

7. A prefabricated building panel as claimed in any one of claims 3 to 6, wherein the mould frame maintains tension to hold the filling material in place.

8. A prefabricated building panel as claimed in any one of claims 3 to 7, wherein the mould frame is configured with an external security device.

9. A prefabricated building panel as claimed in claim 8, wherein the securing device is a protrusion such as a lip.

10. A prefabricated building panel as claimed in any one of claims 3 to 9, wherein the reinforcement structures include steel rods, bar and mesh.

11. A prefabricated building panel as claimed in any one of claims 3 to 10, wherein bolts are welded inside the frame for fitting lifting eyes for manoeuvring the panels once poured.

12. A prefabricated building panel as claimed in any one of claims 3 to 11 , wherein the panel includes electrical conduit.

13. A building structure

characterised in that

the structure includes at least one building panel as claimed in claim 3.

14. A building structure as claimed in claim 13, wherein the building structure includes at least one of the following: electrical connections, cabinet units, cooking units, kitchen and bathroom plumbing units and associated fuel lines, water lines and sewer lines, water taps, smoke alarms, sprinkler systems and other such amenities.

15 A building structure as claimed in claim 13 or claim 14, wherein the lips of a securing device on the building panels are welded together to form a building structure.

16. A building structure as claimed in any one of claims 13 to 15, wherein a plurality of building structures are stacked in a vertical disposition one on top of another.

17. A method of forming a prefabricated building panel substantially as herein described with reference to and as illustrated by the accompanying tables and drawings.

18. A prefabricated building panel substantially as herein described with reference to and as illustrated by the accompanying tables and drawings.

19. A building structure substantially as herein described with reference to and as illustrated by the accompanying tables and drawings.