GB2044819A - Fibre reinforced concrete building panels - Google Patents

Abstract

A building panel comprises a main wall 9 having a skin (13) of fibre reinforced concrete and, integral therewith, a portion 16 or 17 of fibre reinforced concrete which extends in a plane which is transverse of the main wall or skin for strengthening it, and an additional, preferably thinner skin 14 of fibre reinforced concrete. The panels are storey high and filled with insulating material and are tray shaped to define a cavity opening inwardly of the building. A timber framework may be provided and a gutter may be formed integrally with the outer fibre-reinforced cement layer. <IMAGE>

Description

SPECIFICATION Construction of buildings This invention relates to buildings, to panel units for use in the construction of buildings, and to a method of making such panel units.

Whilst most buildings (particularly dwelling houses) are built of bricks, it is also known to construct buildings of panel units which are bolted together to form walls of the building, the panel units comprising concrete slabs reinforced by steel rods or other ferrous reinforcement.

This method of construction has the advantages that it permits a building to be erected relatively quickly and that it uses pre-fabricated units which can be factory-built so that bad weather will not seriously hinder erection of the building as sometimes happens with brick-built buildings. However, a disadvantage of the method is that the panel units are very heavy so that special equipment must be available to manoeuvre the units during building and also to handle the units in the factory and for loading and unloading the units for transportation.

It is an aim of the invention to provide an improved construction of building which enables a building to be erected using factory built panel units but which avoids the disadvantage described above.

A building according to the invention includes panel units constructed largely of fibre reinforced concrete, which panel units partially or completely encapsulate load bearing members, or which are constructed so that, at least when they are erected, the units define permanent formwork for the casting in situ of load-bearing members.

Fibre reinforced concrete comprises a sand and cement mix reinforced by fibres, which fibres may be, for example, of glass or a suitable plastics material. Important properties of fibre reinforced concrete are that the material is relatively strong and durable, but is of relatively light weight. Unlike conventional concrete, fibre reinforced concrete is a resilient material so that it is not likely to be damaged during handling.

In a building according to the invention, structural loads will be carried by the encapsulated or in situ cast load-bearing members, so that the panel units need not be as strong as if they had themselves to bear structural loads. For this reason the units need not comprise solid walls of fibre reinforced concrete, but can instead comprise one or more relatively thin skins of fibre reinforced concrete. For example, the panels may be of sandwich construction, comprising a layer of heat insulating material, such as a polystyrene, disposed between skins of fibre reinforced concrete. The term "fibre reinforced concrete" will for convenience be abbreviated to "FRC" in the following description.

It will be appreciated that the FRC panel units are very much lighter than conventional concrete slabs. It has been found, for example, that an FRC panel unit which is approximately 1 metre wide, two metres high, and encapsulates two load bearing members made of timber can be manoeuvred by two men. Of course, an FRC panel unit will be even lighter if it does not incorporate load-bearing members but is instead designed to form permanent formwork for ferrous reinforced concrete pillars.

It will be understood that the invention also extends to FRC panels for use in constructing a building. Thus, one embodiment of the panel unit according to the invention is designed primarily for use in constructing a wall of a building, the panel unit having at least one skin of FRC and having a side edge wall which is formed with a channel extending along the wall, the arrangement being such that when the panel unit stands generally upright beside a like panel unit, confronting channels in confronting side edge walls of the units together define formwork for the casting in situ of a conventional reinforced concrete pillar.

Another embodiment of panel unit according to the invention is again designed primarily for use in constructing a wall but is also for use in constructing a horizontal floor or ceiling, or a sloping roof, the panel unit having at least one skin of FRC and encapsulating completely partially one or more load-bearing supports made, for example, of timber. The number of encapsulated load-bearing supports and the positioning thereof will be selected according to requirements. For example, a pair of encapsulated load-bearing members may extend parallel to one another, one along each of a pair of opposite side edge regions of a panel unit, and if desired these load-bearing members could co-operate with two further load-bearing members to form an encapsulated rectangular frame.

Whichever embodiment of panel unit is adopted, it is possible to construct the panel units to have a box-section comprised of an FRC skin. It is preferred, however, to construct the panel units to have a main wall portion and integral transverse (side) wall portions one at each end of side edge of the main wall portion arranged so that the panel unit is of channel section. A particular advantage of constructing the panel-units of a building to be of channel section is that the cavity thus formed in the panel unit can be used as storage space.

To provide a channel section panel unit with rigidity it is preferred to construct the main and transverse wall portions to be double skinned, the space between the skins being occupied by, for example, a heat insulating material such as a polystyrene. The skins can also be joined by reinforcing webs made of FRC, and when a panel unit incorporates encapsulated load-bearing supports, these supports may be encapsulated between the double skins and a pair of webs transverse to the double skins providing a box-section cavity.

The channel-section construction can be applied even to panel units which are not in accordance with either of the embodiments panel unit described above, i.e. to panel units which although they are of FRC construction do not incorporate encapsulated load bearing members and do not have channels for defining formwork. Such panels would be useful in the construction of solar panels, or in the construction of a wall which does not have to bear much or any load, for example a link wall connecting a house and a garage.

Such panel units can be reinforced by integral FRC webs arranged so as to form box-section FRC reinforcements as mentioned above. The cavity in a panel unit in a link wall can be used to form a greenhouse, in which case a transparent door could be arranged for closing the cavity. Soil could be contained in a base of the cavity, and the space between double FRC skins could house a water reserve instead of insulation.

Where any panel unit according to the invention is intended for use in constructing a wall, it is preferred to provide the unit with a top wall portion formed with one or more upwardly open troughs extending along the top wall portion. When a number of such panel units are assembled to form a wall, it will be appreciated that they will provide a continuous top wall having one or more troughs extending the length of the wall, and the or each trough may even extend in a continuous ring around a building. Such a trough could serve to provide formwork for a ring beam to be cast in situ could serve to provide a rainwater gutter, or could contain soil for a flower bed or the like.

Although in the above description emphasis has been placed on the use of FRC panel units to construct the wall of a building, the invention also extends to a building having only a floor, ceiling, or roof constructed from double walled FRC panel units of channelsection or box-section construction, which units may be reinforced by integral FRC webs, by encapsulated supports, or by supports cast in situ.

The invention also extends to a method of making an FRC panel unit, and according to a further aspect of the invention such method includes the steps of applying to a mould an FRC skin, placing one or more formers onto the skin, and applying a second FRC skin over the former(s) to provide a panel unit of double skinned construction having one or more formers sandwiched between FRC skins.

The skins are preferably applied by spraying. For example a spray of a sand and cement mix may be directed to the mould, and glass or other fibres may be directed into the path of the spray of sand and cement mix so as to the entrained in such mix.

The or each former may comprise a suitable polystyrene. In this case, several formers may be arranged with gaps between them so that during spraying of the second skin spray fills the gaps to form FRC webs between the FRC skins.

Formers can instead or as well comprise structural load-bearing members such as timer bers.

Preferred embodiments of panel units according to the invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a plan view of a building according to the invention with a roof removed to show the construction of the walls of the building using FRC panel units; Figure 2 is a view in horizontal section of a panel unit of a wall of the building of Fig. 1, the panel unit incorporating encapsulated timber supports; Figure 3 is a view similar to Fig. 2, but showing a modified panel unit suitable for use at a corner of a building; Figure 4 is a view in vertical section of the panel unit of Fig. 2; and Figure 5 is a cross-sectional view showing a possible roof cap for use where two panel units meet at the apex of the roof.

The building shown in Fig. 1 comprises a unit 1 providing living accommodation, a unit 2 comprising a garage and workshop, and a link wall 3 interconnecting units 1 and 2.

The walls of both units 1 and 2 are loadbearing walls which support the weight of a roof and of a horizontal wall (not shown) which will form a ceiling of the units 1 and 2 and also a floor of attic accommodation. In contrast, the link wall 3 is not load-bearing.

The building has various external doors 4 and windows 5.

The load-bearing walls are comprised of panel units 6, whilst the link wall 3 is comprised of panel units 7. Fig. 2 shows in more detail the construction of the panel units 6. As viewed in horizontal section, each panel unit 6 is of channel section, a channel 8 being defined between a main wall portion 9 of the panel and transverse or side wall portions 10 which are integral with the wall portion 9. As will be seen from Fig. 4, the channel 8 is closed at its upper and lower ends by an integral top wall portion 11 and an integral bottom wall portion 1 2 to define a cavity open towards the interior of the building. The wall portions 9,10,11 and 1 2 thus form an integral unit.

The panel units 6 are made of double skinned FRC, i.e. fibre reinforced concrete, the nature and properties of which have been explained above. The outer FRC skin 1 3 is rather thicker than the inner FRC skin 14 in the panel units illustrated, but the skins 1 3 and 14 could instead be of the same thickness. The space between the two skins 1 3 and 14 is filled with a heat insulating material 1 5 such as a polystyrene material. The skins are interconnected by horizontal webs 16, a vertical web 1 7 serving to strengthen the outer skin 1 3. An even greater strengthening could be obtained with two vertical webs to provide a box-section reinforcement enclosing lengths 1 8 of the heat insulating material.

Each panel unit 6 is provided with encapsulated timbers 21 connected to horizontal timbers 40,41 extending in wall portions 11 and 1 2 to provide an encapsulated timber frame.

Instead of having encapsulated timbers, edge regions of the wall portions 10 may be shaped to form vertical channels. The channels of adjacent panel units 6 confront one another to define formwork of box-section which is used for the casting in situ of pillars of conventional concrete reinforced by steel rods. The confronting channels need not be formed at the extreme edge regions of the panel side portions 10, but could instead be formed midway along the wall portions.

Sealing strip 23 are disposed between shallow vertically extending confronting V-section recesses in the wall portions 10.

The cavities formed by the channels 8 may serve as wardrobe or cupboard space, or as alcoves, and suitable fittings such as rails or shelves (not shown) will be provided. Doors (not shown) may also be provided for closing the wardrobe or other space.

Fig. 3 shows a corner panel unit used where two walls of a building meet at right angles. As shown in Fig. 3, at a corner where two panel units 6 meet, the units do not stand side-by-side but are at a right angle to one another. A pair of timbers 26 is bolted to timbers 21 of adjacent units 6 at the corner.

If units with edge channels are used instead of those with encapsulated timbers, a V-section FRC upright is provided to co-operate with two adjacent edge channels of respective units 6 at the corner to define a box-section formwork for the in situ casting of a reinforced concrete pillar. The V-section FRC upright is itself secured in place by means of bolts or the like which connect the upright to wall portions 10 of adjacent units 6.

To complete the corner of the wall, the space 27 is enclosed by an FRC corner unit 28 the construction of which will be readily understood from the drawing. The corner unit 28 is connected to the units 6 at regions 29, and suitable weather seals 23 are provided.

Referring again to Fig. 4, it will be seen that the top wall portion of each wall panel unit 6 is formed with an upwardly open trough 30 and a shelf 31 disposed on opposite sides of a flat portion 32. Fig. 4 shows a roof panel unit 33 the lower edge of which meets the flat portion 32 of the top wall 11.

Also shown, in dotted lines, are an encapsulated timber 21, weather proofing 30a, a rafter 34 and a joist 35. It can be seen that the trough 30 which is disposed on the outside of the building serves as a gutter for rain water, whilst the shelf 31 which is disposed inside the building serves to support a lintel 42. It is preferred that the shelves 31 of all the panel units 6 of the living accommodation unit 1 should be arranged to form one continuous shelf extending around the entire unit 1 so that the lintels will in fact be part of a single continuous ring beam. The building is constructed on a foundation 37 of reinforced concrete. It is preferred to provide rods 41 a projecting upwardly from the foundation 37 into each horizontal timber 41. The provision of such upstanding rods means that the encapsulated timbers 21 can be firmly fixed to the foundation 37.

It will be appreciated that by making the foundation, the upright timbers 21 and the ring beam firmly fixed together, the unit 1 will have a very strong 'skeleton' indeed, making the construction suitable for building in exposed areas subject to gale force winds. The unit 2 will be similarly constructed.

The wall portion 9 may slope at about 5" to provide resistance to damage by high winds.

A method of manufacturing a panel unit 6 will now be described. A suitable mould (not shown) will be provided, the shape of the mould conforming to the shape of the outer skin 1 3 of the panel unit to be moulded. The base of the mould is sprayed with a skin 1 3 of FRC, for example by directing a spray of a sand and cement mix at the mould, and by directing glass or other fibres into the path of the spray so that the fibres are entrained with the spray. After the skin 1 3 has set, or during setting suitably shaped formers of a polystyrene material are positioned in the mould so as to leave gaps between them.Timbers 21, 40 and 41 are then laid in place, and a second and thinner FRC skin 4 is then sprayed over the formers, this second spraying operation filling the gaps between the formers to provide webs 1 6 and 1 7 interconnecting the skins 1 3 and 14. The finished panel unit may be removed from the mould after setting.

The panel units 7 of the link wall 3 shown in Fig. 1 are not required to support a load, and thus need not necessarily have either encapsulated timbers or confronting channels defining formwork for in situ cast pillars. Each unit 7 is designed for use as a greenhouse, and thus has a water reservoir arranged to feed water to soil in a trough. The cavity of the unit 7 is closed by a transparent door. A top wall of the unit has a trough containing soil or a flower bed. Another trough receives a cast in situ beam which interconnects the ring beams of units 1 and 2, Fig. 1.

As shown in Fig. 4, the region where a roof panel unit and a wall panel unit meet may be made weather-tight by an FRC lip seal 58 integral with the roof panel and extending into the gutter trough 30. Alternatively a rubber strip 60 may extend in a space defined between two V-shaped shallow recesses disposed one along the bottom edge of the roof panel 33 and the other along the wall 32.

Similar seals can be provided between the bottom wall 1 2 of a panel unit and the foundation 37.

Fig. 5 shows one design of a roof built from FRC panels. The frame of the roof is constructed from rafters 34 which may be secured to the ring beam structure of lintels 42 described above. FRC roof panel units 33 are secured to the framework of rafters, the length of the units 33 being such that a single unit will span the distance from the ring beam structure to the apex of the roof. At the apex of the roof panel units, caps 71 are provided along the top of the roof for holding the panels together. The panel units 33 are flat, and consist of two skins of FRC reinforced by FRC webs. The roof panel units 33 do not meet at the apex of the roof but are connected by means of projecting plates or lips 81 on the caps 71 which are received in recesses 82 extending along the panel edges.

A number of roof panel units 33 are arranged side-by-side on rafters 34, the panel units being arranged to interlock with one another by an arrangement of projections and recesses to provide a weather seal. The panel units at the end of the roof are connected to FRC gable end units by means of FRC corner pieces.

Instead of being interlocked, adjacent roof panels may merely meet one another at a rafter 34. In this case both panels are recessed to receive projections on a cover strip which can be of FRC and is laid along the junction of the panel units 33.

A cover strip for covering the junction between two roof panels may have alternating wider portions and narrower portions to give a decorative appearance. This cover strip may be secured in place by a mastic adhesive.

The roof panel units may be recessed at their edge regions to receive an edge of a rafter 34.

In order to secure roof panels 33 very firmly in place, T-shaped hold down devices may be used. The cross member of the hold down device overlaps edges of adjacent roof panel units 33, whilst the stem of the hold down devices passes between adjacent panel units and through a rafter. A nut is screwed onto a threaded end of the stem.

A similar cover strip may be used for joining a roof panel unit 33 to an FRC gable end unit.

An FRC floor panel unit may be made with two FRC skins and with a layer of insulating material between them. The floor panel unit may be provided with reinforcing webs (not shown), and these webs could encapsulate timbers, or a timber frame as in the case of the wall units.

Adjacent floor panels may be recessed to receive timbers which serve to provide a kind of tongue-and-groove connection.

Each floor panel unit may extend the width of a building and may be supported by a sand-cement grout or bedding.

Various minor modifications will now be described. Although the roof panel units are shown in the drawings, as having an outer weathering face or skin which is flat, it can instead be cast to reproduce the surface details of any roof that one wants to simulate, for example a tiled roof. Any of the joints between adjacent panel units may be arranged to be hidden by cover strips which serve to break vertical lines. The roof units may be strengthened by encapsulated timber purlins to increase structural strength and to allow for greater spacing in roof trusses.

Openings for windows, chimneys, vents, cables and aerials may be provided in panel units. When a panel unit is used to form a ceiling, one face of the panel unit may be provided with a suitable ceiling finish during manufacture.

An angled FRC cover completing the enclosure of an upright post of the timber frame structure may be used.

instead of casting concrete posts in situ into the building panels, or using units with encapsulated timbers, a house like that shown in plan in Fig. 1 can be constructed by first erecting a timber frame and then assembling building units around the frame. In this case the units will have channels or recesses for receiving parts of the timber frame. The frame may be built on a stepped foundation.

Three different possible roof panels are a standard textured panel, an integrated solar panel, and an integrated velux panel.

Claims (28)

1. A building panel unit comprising a main wall or skin of fibre reinforced conrete and, integral therewith, a portion of fibre reinforced concrete which extends in a plane which is transverse of the main wall or skin for strengthening it or for use in strengthening it.

2. A unit according to claim 1, in which at least one closed-section cavity is defined by fibre reinforced concrete which is integral with the main wall or skin, a load-bearing member being inserted or casted in the cavity in situ when the unit is used in the erection of a building.

3. A unit according to claim 1, further comprising at least one load-bearing member encapsulated in a closed-sectional fibre reinforced concrete portion of the unit which is integral with the main wall or face.

4. A unit according to claim 2 or claim 3, wherein the closed section is a box section.

5. A unit according to claim 3 or claim 4, in which the load bearing member or members are timber supports.

6. A unit according to any one of claims 3 to 5, in which there are load-bearing members defining a frame.

7. A unit according to claim 1, in which a fibre reinforced concrete portion of the unit which is integral with the main wall or face defines a channel for a load-bearing member.

8. A unit according to claim 7, in which at least a part of a load-bearing member extends along and within the channel.

9. A unit according to claim 7, in which the channel is so arranged that another like unit can be located alongside the first with respective channels of the two units defining a permanent form-work for casting a load-bearing member in situ.

1 0. A unit according to any preceding claim, in which the unit is of a double-skinned fibre reinforced concrete construction.

11. A unit according to claim 10, the double-skinned unit being formed with side edge walls so as to have a channel section.

12. A unit according to claim 10, in which the two skins are joined by two transverse portions, integral with the two main skins, along opposite edges of the unit so that the concrete has a box section.

1 3. A unit according to claim 10, 11 or 12, in which the intended outer skin is thicker than the intended inner skin of the doubleskinned construction.

1 4. A unit according to any one of claims 10 to 13, wherein at least one transverse web of fibre reinforced concrete which is integral with at least one of the two skins extends between them at a location which is inward of the edges or ends of the unit.

15. A unit according to claim 14, in which the or at least one of the transverse webs constitutes part of a box-sectioned cavity for containing a load-bearing member inserted or casted in the cavity in situ when the unit is used in the erection of a building.

16. A unit according to claim 14, further comprising at least one load-bearing member encapsulated by fibre reinforced concrete of the unit, the or at least one of the transverse webs serving as an encapsulating portion.

1 7. A unit according to any one of claims 10 to 16, wherein one or more formers are sandwiched between the two skins.

1 8. A unit according to claim 17, wherein the former or formers are made of a heatinsulating material, such as polystyrene.

1 9. A unit according to any preceding claim, formed with an upwardly open FRC trough which is integral with the or a main wall of skin of the unit and which forms part of a gutter around the roof when the unit is positioned in a completed building.

20. A building panel unit substantially as described herein with reference to any one of the Figures of the accompanying drawings.

21. A building comprising at least one unit as claimed in any preceding claim.

22. A building according to claim 21, in which horizontal elongate load-bearing members embraced by portions of the units extend as a ring round the building through the walls thereof.

23. A building substantially as described herein with reference to the accompanying drawings.

24. A method of making a unit as claimed in any preceding claim, comprising applying fibre reinforced concrete to a mould to form a skin thereon.

25. A method according to claim 24, in which one or more formers are placed onto the skin, and fibre reinforced concrete is applied to the former or formers to provide a panel unit of double skinned construction having one or more formers sandwiched between fibre reinforced concrete skins.

26. A method according to claim 25, in which there are at least two formers with a gap between them so that a web of concrete is formed between the two skins.

27. A method according to claim 24, 25 or 26, in which the concrete is applied by spraying.

28. A method according to claim 27, in which a spray of sand and cement mix is directed at the mould or forming or formers, and glass fibres or other fibres are directed in the path of the spray so that they are entrained therein.