WO2008058711A1

WO2008058711A1 - A composite panel

Info

Publication number: WO2008058711A1
Application number: PCT/EP2007/009818
Authority: WO
Inventors: Gordon Forbes
Original assignee: Finrone Limited
Priority date: 2006-11-13
Filing date: 2007-11-13
Publication date: 2008-05-22
Also published as: GB0622521D0; EP2099981A1

Abstract

The present invention provides a composite building panel (10) having particular application in animal housing, the panel (10) comprising an insulating core sandwiched between inner and outer layers (12, 14), a timber frame (18) surrounding the core (16), and a water.impermeable membrane (30) provided on a ground contacting base of the panel.

Description

A Composite Panel

Field of the invention

The present invention relates to a composite panel, in particular a composite panel for use in buildings. The composite panel is particularly suitable for use in constructing walls in buildings for animal housing and the like.

Background of the invention

In conventional buildings used for animal housing, the frame of the building is normally built on-site with an option to cover the frame with a sheeting material, e.g. polyethylene sheeting. The outside of the frame, or the sheeting material, is normally covered with sheets of rigid insulation, and finally a finishing layer is applied over the insulation sheets. The finishing layer can be made of bricks, stone, or other known materials. Although these buildings provide a secure structure, they have a number of disadvantages. The step-by-step nature of the construction means that the construction is time consuming and labour intensive. A number of builders are required to be present, which results in the construction also being costly.

A further problem that can arise in conventional buildings is the problem of moisture damage. Water entering the building from outside can penetrate the walls of conventional buildings, causing damage to the panels and having an ill effect on the animals in the building.

Accordingly, it is an object of the present invention to mitigate at least some of the afore-mentioned problems. It is a further object of the present invention to provide a composite panel which facilitates the construction of the buildings, such as animal housing, more quickly and efficiently than is currently known.

Summary of the invention

According to a first aspect of the present invention, there is provided a composite building panel comprising first and second layers; an insulating core disposed between the first and second layers; and a substantially water impermeable membrane about a base of the panel.

Preferably, the panel comprises a frame surrounding the insulating core.

Preferably, the membrane is provided on the frame.

Preferably, the membrane extends from the base onto at least a portion of each of a pair of side edges of the panel.

Preferably, the frame comprises timber.

Preferably, the first layer comprises a fibre-reinforced material.

Preferably, the first layer comprises a plurality of sub layers.

Preferably, the first layer is adhered to the insulating core.

Preferably, the first layer comprises a substantially smooth outer surface.

Preferably, the second layer comprises a fibre-reinforced material.

Preferably, the second layer comprises a plurality of sub layers. Preferably, the second layer is adhered to the insulating core.

Preferably, the second layer comprises a substantially textured or embossed outer surface.

Preferably, the panel comprises a reinforcing layer provided on the first layer.

Preferably, the panel comprises one or more batons disposed internally of the panel.

Preferably, the or each baton is oriented to extend, in use, substantially horizontally.

Preferably, the or each baton is substantially disposed within the insulating core.

Preferably, the panel comprises cooperating connecting means provided on at least a pair of opposed edges of the panel.

Preferably, the first layer and/or the second layer are adhered to the insulating core by an adhesive.

According to a second aspect of the present invention there is provided a building for animal housing comprising a portal frame and a plurality of the panels of the first aspect of the invention.

As used herein, the term "timber" is intended to mean wood in general, both in terms of planks, sheets, or other elements formed from a single type of wood, sheets of plywood, or sheets of fibreboard or the like. Brief description of the drawings

The present invention will now be described with reference to the accompanying drawings, in which:

Figure 1 illustrates a partially cut-away perspective view of a composite panel according to the present invention, illustrated from a first direction showing a first layer of the panel; and

Figure 2 illustrates the composite panel of Figure 1, illustrated from the opposite direction of Figure 1 and showing a view of a second layer of the panel.

Detailed description of the drawings

Referring now to the accompanying drawings, there is illustrated a composite building panel, generally indicated as 10, for use in buildings, and in particular for use in constructing walls in buildings for animal housing and the like. The panel 10 provides many improvements in the construction of such animal housing buildings, as will be understood from the following description.

Referring to the partially cut-away views shown in the drawings, the panel 10 comprises a first layer 12, a second layer 14, and an insulating core therebetween. Although the insulating core is not shown in the drawings, it is indicated as 16, to indicate where it is found in the panel 10. The panel 10 preferably comprises a timber frame 18 surrounding the insulating core 16. The panel 10 preferably comprises a pair of opposite substantially parallel edges at the sides thereof. Since Figures 1 and 2 are partially cut-away views, only one of the side edges, indicated as 24, is shown in the drawings. The panel 10 also preferably comprises a pair of substantially parallel edges at a top 20 and a base 22 thereof. The panel 10 is conveniently provided with a substantially water impermeable membrane about the base 22. The membrane preferably extends from the base 22 onto at least a portion of each of the side edges 24 (only one shown). The membrane is preferably made from plastic or the like, and is in the form of a strip 30 as shown in Figures 1 and 2. The strip 30 conveniently acts as a moisture barrier. This is especially useful when a number of panels 10 are used to construct a wall (not shown) of a building (not shown). The strip 30 prevents water from entering the building from outside. In addition the strip 30 prevents moisture from entering the panels 10, which would otherwise result in water damage over time, in particular to the timber frame 18, thereby reducing the thermal efficiency of the panel 10. As a result, the presence of the strip 30 removes the need for a purpose built floor in such a building, as the fact that the panels 10 are provided with a moisture barrier means that they can be erected directly on the ground, if desired, with the possibility to omit any additional weather sealing.

The first layer 12 preferably comprises a single layer of fiber reinforced material, in particular but not exclusively glass reinforced plastic. However, it will be appreciated that the first layer 12 may comprise more than one layer if desired, for example a laminate of several sub layers (not shown) and any other suitable material may be used. The first layer 12 preferably has a thickness of about

1.5mm. The first layer 12 has an inner surface (not shown) facing the insulating core 16 and which, in use, is adhered to the insulating core 16, and an outer surface 13 which is substantially smooth. The panels 10 are positioned, when forming the wall of a building, with the outer surface 13 facing the interior of the building to form at least part of the interior surface of the wall. The outer surface 13 thus provides a surface which is easily wipeable and therefore hygienic, which is particularly useful in a building used for animal housing.

The second layer 14 also preferably comprises a single layer of fiber reinforced material such as glass reinforced plastic. However, it will again be appreciated that, if desired, the second layer 14 may comprise more than one layer, and may be made from any other suitable material. The second layer 14 preferably is of a thickness of about 2mm. The second layer 14 has an inner surface (not shown), which, in use, is adhered to the insulating core 16, and an outer surface 15 which is textured or embossed. When forming the wall of a building, the panel 10 is positioned such that the outer surface 15 faces and forms the exterior of the building. The outer surface 15 therefore provides the exterior of the building with an appealing appearance. The second layer 14 may be suitably colored to be sympathetic with the surrounds, which will generally be a rural environment, and thus is a preferred embodiment may be colored green.

The insulating core 16 is preferably made from extruded polystyrene foam due to its excellent insulation value, high mechanical strength and almost complete resistance to water absorption. Further important properties of the polystyrene include low thermal conductivity, high compressive strength, high resistance to long term compressive stress, high tensile strength, homogeneous density, excellent shear strength, resists mould and fungal growth, will not rot, good lamination surface, available planed to close tolerances, clean and easy to use, properties unaffected by any damage to the first and second layers. The excellent spanning capabilities of extruded polystyrene, when sandwiched between the first and second layers 12, 14 to form the composite panel 10, renders the panels 10 particularly suitable for use in portal frame buildings having a clear span allowing for ease of maintenance and cleaning. The spanning capabilities of the panel 10 also allow the use of fewer panels per building meaning less joins between panels 10, which may harbor bacteria. The panel 10 also embodies high resistance to impact and moisture and outstanding strength-to-weight characteristics, and so is particularly suitable for maintaining the temperature for animals across a broad range of environmental temperatures. The extruded polystyrene foam core preferably contains grooves (not shown) or other surface texturing to ensure the finished material is ideal for lamination to metal, plywood or plastic facings. The grooves are preferably 40mm apart, 3mm deep and 1.8mm wide. Preferably, the first and/or the second layers 12, 14 are adhered to the insulating core 16 by an adhesive. In this way no mechanical fixings which would pierce the first and/or second layers 12, 14 are required. This maintains the integrity of the outer faces of the panel 10 helping to improve the thermal efficiency and weather resistance of the panel 10. The adhesive may be any suitable organic and/or inorganic adhesive, or a mixture thereof, and whilst not limiting the invention thereto, a particularly suitable adhesive is a polyurethane type adhesive. It will be appreciated that if a polyurethane type adhesive is to be used, either the finished polyurethane adhesive may be sourced, or the raw materials, e.g. including isocyanates and polyols and any other necessary additives, may be sourced and combined to produce a polyurethane type adhesive.

Referring to Figure 1, the first layer 12 may be provided with a reinforcing layer, for example a metal wall such as a stainless steel reinforcing wall 32, bonded thereto. The reinforcing wall 32 is preferably substantially square in shape and may be up to about half the height of the panel 10, as shown in Figure 1. The reinforcing wall 32 preferably has a thickness of about 9mm, and serves to provide further strength to the panel 10, which is particularly useful when the panel 10 is to be used in an animal housing, where strong walls are desired. The coating wall 32 may be adhered to the first layer 12 using any suitable means, e.g. adhesive.

Preferably, the panel 10 may be connected to a number of substantially identical adjacent panels (not shown) using any suitable connecting means (not shown). The connecting means are preferably provided along at least two opposing side edges of the panel 10. Suitable connecting means may include, but are not limited to, male and female connectors, such as a tongue and groove arrangement, to form a snap-fit or interference fit. Alternatively or additionally, the connecting means may comprise one or more latches or cam locks. It will be appreciated that any suitable arrangement of these or any other connecting means may be used. Advantageously, when adjacent panels 10 are connected, their top and base edges are flush and do not form any grooves. The joint between adjacent panels 10 is not readily noticeable. Once the panels 10 are installed, no further finishing is required. In the case that the connecting means between the panels 10 are made of the same materials as the panels, the connecting means between adjacent panels can be slightly compressed when joining the panels together. This ensures that the respective top and base edges of adjacent respective panels will tightly abut against one another thus minimizing the size of the joint, and thus minimizing its appearance, between the panels.

As shown in the cut-away views of Figures 1 and 2, the panel 10 preferably includes one or more batons 26, 27 disposed internally of the panel 10, and preferably substantially within the insulating core 16. In Figures 1 and 2, the panel 10 has been cut away to expose baton 26 which is substantially parallel to the side edge 24, and a number of batons 27 which are substantially parallel to the base 22. The lowermost baton 27 forms a base of the timber frame 18 and onto which the membrane 30 is secured. The outermost batons 26 also form the sides of the timber frame 18. The timber frame 18 is conveniently provided to enable fixings (not shown) to be secured to or against the panel 10, in particular on an interior of a building (not shown) formed with the panels 10. Similarly, the timber batons 26, 27 provide the panel 10 with further means for securing fixings to the panel 10. For example, the supporting beams 26, 27 are particularly useful if e.g. a window (not shown) is to be fixed within the panel 10. It will however be appreciated that the frame 18 and/or batons 26, 27, need not be present. In this way, the panel 10 can be adapted to suit any particular need. In Figures 1 and 2, if the baton 26 was not present, the cut-away view would expose a portion of the insulating core 16. The timber frame 18 does however protect the panel 10 from vermin and insects.

In an exemplary embodiment, the panel 10 has the following details: a polystyrene insulating core 16 of thickness 75mm; a first layer 12 of thickness 1.5mm, made of white fiberglass; and a second layer 14 of thickness 2mm, made of green textured fiberglass. The overall dimensions of the panel may be adapted as desired in accordance with any requirement. The panel 10 is not limited hereto, and the first and second layers 12, 14, may be smooth, roughened, provided with a pattern, formed as imitation brick or stone and/or coloured as desired.

It is envisaged that the panel 10 will preferably be used in the construction of a building for animal housing, in particular for housing pigs of all ages, or poultry or the like. In this case, the building for animal housing would preferably comprise four walls, each wall comprising a number of adjacent composite panels 10 joined at the side edges, and a roof supported on said walls. The panels 10 may be used to construct walls for each of the following types of buildings, which are given by way of example only, and are not intended to limit the use of the panels 10.

(A) Portable Buildings

Standalone units (4.2 metres wide) of portable pig housing aimed at all the stages of pig rearing: farrowing/maternity, the accommodation of the pig sow and her piglets from birth to 28 days/8kgs, weaning/nursery buildings for the piglets from weeks 4-9.

Specifications of examples of portable buildings are given below:

1. Farrowing Building Specification

• Farrowing Crates with tumble out stainless steel troughs • Plastic sow slats supported on 120mm fϊbreglass beams carried on stainless steel supports

• All plumbing stainless steel and plastic pipe with water nipples

• Flush fitting heat pads 1.2m x 0.4m

• PVC board profile penning 500mm x 40mm fitted on stainless steel slides • All internal electrics waterproof with a socket for heat lamp. • Four 800mm x 500mm double glazed windows 2 of which are fail-safes

• Exterior green fibreglass sheeting - part of the panel 10.

• Pitched fibreglass roof, white with stainless steel edging

• One Fibreglass slurry tank per room with a 1° fall towards a 150mm outlet • 70mm insulation in walls (part of the panel 10) and 150mm in the ceiling

• Controller giving positive ventilation c/w 1 no. 14" fans, alarm and siren

• Internal walls clad with white fibreglass sheeting - part of the panel 10

• One external PVC door (standard per building), 2 doors per 2 room building plus 1 internal door

2. Nursery Building

• Available in 1 or up to 4 rooms per building • Choice of no. of pens, size and layout

• Exterior green fibreglass sheeting - part of panel 10

• Internal walls clad with smooth white fibreglass sheeting - part of panel 10

• One 0.5m deep fibreglass slurry tank per room with 1° fall towards a 150mm outlet • External PVC doors

• Pitched fibreglass roof and stainless steel edging with PVC ventilation outlet and fan boxes

• Computerised ventilation c/w fans, alarm and heaters

• 70 mm insulated wall (high density, part of panel 10) and 150mm roof insulation • S/steel heaters c/w safety guards

• Double Glazed Fail-safe windows 80cm x 70cm

• Feeders

• Weaner slats supported on 120mm fibreglass beams

• Penning 75cm high PVC 40mm board profile • All plumbing stainless steel and plastic with drinkers • All internal electrics waterproof with all controls in an exterior box

3. Grower Building

• The building is delivered in 2 sections and joined together by a Im wide walkway onsite

• Available in 1 or up to 4 rooms per building (10m - 19m in length x 9m wide)

• Choice of no. of pens, sizes and layout

• Exterior walls green fibreglass sheeting - part of panel 10 • Interior walls white fibreglass sheeting - part of panel 10

• 70 mm insulated wall (high density extruded polystyrene, part of panel 10)

• 150 mm fibreglass insulation in the ceiling

• 2no. Fibreglass slurry tank per room with a 1 degree fall towards 150mm outlet

• 30cm X 80cm Trapper slats on 120mm fibreglass beams supported by stainless steel

• 5 degree pitched fibreglass roof c/w PVC fan boxes and ventilation outlets

• Computer controller c/w 2 No. Fans, EGM-100A Servomotor

• Air intake flaps

• 1 no. 40 cm external PVC Stainless Steel edged door • S/steel and Im high PVC penning system

• 80cm x 70cm PVC Fail-safe windows

• 3 in 1 feeders

• Water Nipples / Bowls

• All plumbing pipes made of plastic and stainless steel c/w water header tank per room

• All internal electrics waterproof with all controls in an exterior box

The standard portable building comprises the following:

i. Mild Steel Slurry Tank - the mild steel tank is cut and folded to size. Once the profile of the tank has been welded together the floor area of the tank is decked using 18mm plywood. A 600g/m² chopped fibreglass mat covers the plywood and then a fibreglass resin is applied to the mat. When the resin has set and hardened a gel coat is applied to complete the tank.

ii. Internal Floor - Inside the mild steel slurry tank 100mmx50mm &

50mmx50mm stainless steel box section runs horizontally across the width, this is to support the internal floor of the building. On top of the Stainless box section reinforced fibreglass beams (GRP) 120rnmx6000mm run vertically across the length of the building and the polypropylene floor is then fixed into place on top of the beams.

iii. Wall Panels - The wall panels 10 for the buildings are as described above. These panels 10 are manufactured specifically for each building due to building size, windows, door ways and ventilation inlets. These panels 10 will be erected on the buildings at the factory site. Once the walls are erected the windows, doors etc are then fitted.

iv. Roof - Timber trusses assembled in the workshop are fastened to the top of the erected wall panels. These trusses are positioned 400mm apart and are sheeted with an insulated bonded panel inside the building. The external face of the panels is white PVC and is fastened to the timbers with H and U rail and insulation screws. On the exterior side of the roof the complete area is decked using 18mm plywood then covered with 600g/m² cross strand mat followed by the resin and the gel coat. Once the gel coat has hardened the roof is trimmed and is finished with stainless steel fabricated facia around the perimeter.

v. Internal Fittings: Depending on the type of building purchased the building's can be kitted out using various materials. For example the farrowing building is divided into a number of equally sized pens. Inside each pen will be a galvanised mild steel crate 6 no cast iron slats, 1 no heating plate on the floor and a drinking bowl for the small piglets. The penning divisions in a farrowing building are normally 50cm high and are joined using various stainless steel posts that are fabricated in the engineering workshop.

vi. Electrical Control & Ventilation System. Includes ventilation equipment, standard lighting and wiring.

Advantages of the Portable Buildings

The Portable unit has a number of competitive advantages over competitors: - the productivity of the pigs housed in the units is better due to the higher level of disease control.

- it can be easily washed down and does not create the moisture common in traditional pig housing.

- the house is computer climate controlled - i.e. both the temperature and air flow are regulated - there are fewer deaths during the rearing process, faster growth, good quality carcases and less feed is required.

- the unit is treated as Portable agricultural capital equipment for taxation purposes and can be bought on HP.

- this type of housing is attractive to farmers considering retiring or leaving the agricultural sector relatively soon as it has a good resale value.

- as the units are under the 600 sq metres, for the expansion of agricultural buildings - they do not require Planning permission.

- in terms of price, the unit costs around 5% more than conventional housing however this is attractive to farmers interested by the preceding competitive aspects.

(B) Kit Buildings

The kit version of the portable building is delivered on-site and assembled on-site. Whilst it is similar to the above product, it does not have an integral slurry tank.

The product is usually sold to farmers that have a requirement for larger units than the built units - Kits are sold in widths of 6 and 8.5 metres wide. Kit units can be to larger sizes as they are erected on site. Kit Buildings are a new way of erecting on site, agricultural type buildings. These buildings are easily and quickly assembled and are an excellent environment in which to accommodate various types of animals.

Each kit building will have a specific layout and will include concrete slurry tank layout and dimensions, internal floor layout, positioning of air inlets, windows, doors and panels to be used in the roof layout.

The kit building comprises the following:

i. Concrete Slurry Tank - The slurry tank on-site is concrete and is built on-site. The tank walls are used to support the reinforced fibreglass beam that support the internal floor and the wall panels 10 that are used in the perimeter of the building.

ii. Internal Floor Layout - Reinforced fibreglass beams 120mm x6m span across the width of the concrete tank. The beams are supported every 2m with reinforced fibreglass legs. The polypropylene slats are then fitted onto the beams covering the area of the floor. This is why a detailed layout is so important at early stages as the floor has to fit the building exactly.

iii. Wall Panels- The wall panels 10 supplied are as described above and are made specifically for each building. Panels 10 fitted around the perimeter of the building come with all air inlets, window and door position already cut out of the panels.

Once the panels are erected the inlets and door frames etc can be fitted.

iv. Roof Section - The roof panels are fitted into place on top of the wall panels 10. The panels span the width of the building and are supported by 40x40mm stainless steel box section every 2m inside the building. Above the bonded roof panels three timber- framed ladders run the length of the building. These ladders support the external curved aluminium profiled roof sheeting that also spans the width of the building. The curved aluminium sheet is then fastened to the timber-framed ladders and a spouting is fitted at each side.

v. Internal Fittings: Internal fittings are determined by the size of the pigs to be accommodated in the building. At the early stages of the building design a layout of the internal fittings is produced;

Advantages of Kit Buildings:

The Kit form building has the same features and competitive advantages as the Portable building along with the following:

- Ability to be assembled on site at the farm.

- Reduced transport costs as a number of Kit Buildings can be transported at once

(C) Portal frame buildings

The portal frame buildings will have the same internal equipment and specifications as the above products. The product is based on a Portal frame on which the composite panels 10 described above can be fitted. It allows the builder to provide a fast building of high quality that can be to whatever size and internal specification that the farmer requires. Internal fittings and layout can be adapted for the different stages in the pig growth cycle.

These buildings are constructed on site and comprise:

i. Mild Steel Portal Frame (Painted or Galvanised)

ii. Bonded Insulated Panels - The panels 10 can be fitted to the outside or the inside of the Portal frame and are fastened using stainless steel coach screws, bolts and lock nuts. The bottom of the panel 10 is cemented and the top is enclosed to the ceiling sheet. A stainless steel sheet may be bonded onto the panel 10 as hereinbefore described. This gives the panel 10 more durability for larger type animals and is easily maintained and cleaned. All panels 10 arrive on-site with all openings for window and doors etc cut and trimmed, as this reduces labour on-site. The windows and inlets are then fitted on-site.

iii. Roof Section- There are various ways in which air can be ventilated through these buildings. Either high or low level ceilings can be accommodated in these buildings. In a low level ceiling the air is drawn into the building through small holes in an insulated ceiling panel and extracted through a ceiling fan. These panels are made from extruded polyurethane and come in sheet sizes of 2.4m x 0.6m x 0.03m. Each panel has a tongue side and grove side and is fastened to the timber bridging in the roof using insulation screws. In a high level ceiling the air can be drawn into the building through Scan Air inlets placed in the ridge of the roof. These inlets are connected to a winch motor and the inlets are automatically adjusted depending on the temperature inside the room. The insulated ceiling panel used in the roof again is a polyurethane board but has a 1 mm sheet of white PVC bonded on both sides. These bonded boards will come in various sizes and thicknesses depending on the specification.

iv. Internal Fittings - Again these can be specified according to customer requirements. For example for Farrowing Buildings there is an individual pen for each sow. Each pen will consist of the farrowing crate, one heat pad 120cmx40cm, six black cast iron slats and the remainder of the floor slatted with green polypropylene farrowing slats. There is also a small drinking bowl for the piglets and pens are divided using a white profile board 500mm high.

For layouts accommodating weaner and grower pigs, the internal fittings can be changed. Advantages of Portal Buildings

These products have traditionally been built using timber and utilising Rockwall insulation in the wall and ceiling panels. The construction of these units requires floor posts to support the ceiling. The advantages of the Portal frame building over both these types of buildings and conventionally built pig and poultry housing are as follows:

- There is no requirement to build a foundation and base of around 60-80 centimetres above the ground as the panels 10 will be able to sit directly on the ground due to the plastic strip 30 provided on the base of the panel 10.

- As there is no central support beam, i.e. the building is described as a "clear span building", there is greater space utilisation and it is easier for farmers to work in.

- The finished buildings is easier to wash properly due to the clear span as there will be no internal support posts.

- It is estimated that it would have almost twice the insulation value of competitors' panels which use polystyrene.

- Low/no maintenance required

- The poultry sector normally uses a mechanical vehicle such as a Bobcat to remove the old animal waste from poultry houses - the new building facilitates its greater manoeuvrability.

It will be apparent from the above description that the panels 10 have many uses. The panels 10 may also be used for example to provide refrigeration units in trucks or fixed temperature control stores (now shown). The panels 10 have many advantages over conventional construction panels. For examples, the panels 10 can be applied directly to build a house for which there is no existing frame, or they can be applied to a portal frame structure.

The panel 10 is advantageously light enough that it can be easily applied to a small building by only one or two people without requiring the use of handling machinery or equipment, with no further on-site work, other than handling, fitting and fastening the panels, needed to complete the installation, and which presents a pleasing appearance due to the finish of the layers 12, 14. The panel 10 lends itself to construction off-site and easy assembly on-site. The adhesive used in the panel 10 has been found to provide a better bond than found in conventional panels, and therefore gives reduced labour costs and improvements in production time.

Claims

1. A composite building panel comprising first and second layers; an insulating core disposed between the first and second layers; and a substantially water impermeable membrane about a base of the panel.

2. A panel according to claim 1 comprising a frame surrounding the insulating core.

3. A panel according to claim 2 wherein the membrane is provided on the frame.

4. A panel according to claim 2 or 3 wherein the membrane extends from the base onto at least a portion of each of a pair of side edges of the panel.

5. A panel according to any preceding claim in which the frame comprises timber.

6. A panel according to any preceding claim in which the first layer comprises a fibre-reinforced material.

7. A panel according to any preceding claim in which the first layer comprises a plurality of sub layers.

8. A panel according to any preceding claim in which the first layer is adhered to the insulating core.

9. A panel according to any preceding claim in which the first layer comprises a substantially smooth outer surface.

10. A panel according to any preceding claim in which the second layer comprises a fibre-reinforced material.

1 1. A panel according to any preceding claim in which the second layer comprises a plurality of sub layers.

12. A panel according to any preceding claim in which the second layer is adhered to the insulating core.

13. A panel according to any preceding claim in which the second layer comprises a substantially textured or embossed outer surface.

14. A panel according to any preceding claim comprising a reinforcing layer provided on the first layer.

15. A panel according to any preceding claim comprising one or more batons disposed internally of the panel.

16. A panel according to claim 15 in which the or each baton is oriented to extend, in use, substantially horizontally.

17. A panel according to claim 15 or 16 in which the or each baton is substantially disposed within the insulating core.

18. A panel according to any preceding claim comprising cooperating connecting means provided on at least a pair of opposed edges of the panel.

19. A panel according to any preceding claim in which the first layer and/or the second layer are adhered to the insulating core by an adhesive.

20. A building for animal housing comprising a portal frame and a plurality of the panels of any of claims 1 to 19 fixed to the frame.