IE47571B1 - Facing elements - Google Patents

Abstract

An exterior facing for roofs or walls of buildings can be formed of overlapping or butt jointed elements that may be over a non-watertight underlayer, the elements consisting of mineral wool containing a bonding agent and having the fibres oriented substantially parallel with the exterior surface.

Description

The present invention relates to an external facing for surfaces or roofs of walls and which may be mounted ih the form of overlapping or butt jointed slabs or other elements that may be over a non-watertight underlayer and at an inclination in order to drain off the precipitation.

Facings of this type for buildings are generally formed of a hard and impermeable material, which is waterproof and substantially airtight. Preferred materials are metal, tile or asbestocement.

These materials have some disadvantages unless they are used with an internal insulation which prevents a large transmission of heat and prevents condensation of water on the inside of the facing. In non-heated store-houses, garages and similar buildings comprising a simple construc15 tion with walls consisting of only the layer forming the shield against the rain, condensation of water causes considerable problems. For instance it can cause serious damage to goods or machines stored in the building.

A roof or wall according to the invention has an ex20 ternal face that is provided by the outer surface of bonded mineral wool elements and that is inclined to the horizontal so that precipitation drains off the external face and the fibres of the elements at least in the layer adjacent the outer surface are oriented substantially parallel to the surface.

The invention is based on the observation that a body comprising bonded mineral wool and with the fibres oriented substantially parallel with the surface of the body is impermeable to rain and other forms of precipitation. The outside surface, for instance to a depth of a couple of millimeters, will weather and the bonding agent partly decompose, but under this surface layer the mineral wool will stay intact and keep its water-repellant properties because of the protection provided by the weathered surface. The mineral wool is permeable to air and vapour and thus will prevent or reduce condensation and so the disadvantages discussed above will be avoided or minimised.

As a result, for instance, a roof may be constructed that is completely solid and that is not provided with the normal ventilation on its inside face. Thus as a result of the invention, the roof can be constructed without the normal laths and rafters and the facing on the roof can be part of the heat insulation of the building. Since there can be no ventilated hollows into which snow may find its way this also has the advantage of improving impermeability to snow. Impermeability to rain or snow may be achieved by mounting the elements with tight seams, for example by gluing. Because of the elasticity of the mineral wool a plastic sealant is not necessary in the seams.

Due to the low heat transmission a good insulation is obtained. Insulation may be provided solely by the facing or the facing may be fitted over other insulation.

For instance the facing may be fitted over old insulation.

Since the fibres are oriented substantially parallel to the surface, the weathering of the mineral wool is a slow process, and capillary action into the thickness of the mineral wool is substantially prevented.

The elements may be in the form of panels of any convenient dimensions, for example as planks. One longitudinal corner edge of each plank or other panel is preferably recessed when the panels are to be overlapped, e.g. on an inclined roof. The elements may be provided with an indentation in order to drain precipitation. They may be butt jointed or overlapped.

If it is necessary to provide a membrane impermeable to air or vapour, this membrane should be placed closely adjacent to the inside of the interior surface of the insula tion. When the only insulation is the described facing then the membrane will be on the inner face of the facing. The air- or vapour-impermeable membrane may then be a layer sprayed or glued directly on the facing.

Preferably according to the invention the tensile 2 strength of the surface layer is more than 1 kp/cm , so as to prevent the surface layer being disentegrated by weather conditions.

The mineral wool preferably has a specific weight 2 above 50 kg/m and an air permeability below 0.62 m/h mm W.C. The air permeability states the amount of air passing 2 through aim slab of mineral wool per hour with a fall in pressure through the slab of 1 ram water column per m.

The mineral wool may be produced from fibres being collected on a perforated conveyor passing at the end of a spinning chamber into which a thermosetting bonding agent is atomized. The bonding agent may be a phenolic resin for example a phenolformaldehyde resin, or possibly a flexible type of phenolic resin such as a latex or acryl - 5 modified phenolic resin which latter are more resistant to impacts from hail and other hard objects hitting the facing. The layer of mineral wool is compressed simultaneously with setting or curing of the bonding agent. The compression must be sufficient for obtaining a specific weight of the mineral wool in excess of 50 kg/m and in most applications preferably more than 100 kg/m2.

It is possible to increase the compression further and optionally, to corrugate the slabs, in order to increase the strength sufficiently to be able to increase the distance between the supports.

The mineral wool may be dyed in the manufacturing process with a suitable dye, or the facing may be painted after its mounting. Further it is possible to use a raw material in the manufacture producing dark or black fibres. The water-repellant properties of the mineral wool may be improved by a silicone treatment in order to reduce the weathering rate, which, dependent on the climatic conditions, is a few tenths of a millimetre per year.

The invention is described in detail in the following with reference to the drawings, showing examples of building constructions with the external facing according to the invention.

Figure 1 shows a section through part of a roof in a building faced with slabs of mineral wool, and Figure 2 shows a section through a house, which is provided with an additional insulation.

The building shown in Fig. 1 has no insulation apart from the insulation provided by the rainproof external - 6 facing. The building comprises vertical studs 1 and rafters 2, supporting and carrying wall facing slabs 3 and roof facing slabs 4 respectively. The roofing 4 is fixed, for example by means of nails 5 with washers under the heads of the nails, to beams or laths 6, running perpendicular to the rafters. The roofing is made from overlapping slabs 7 of mineral wool containing a bonding agent, the fibres of the mineral wool being oriented in directions substantially parallel with the surface. The orientation of the fibres may be the same throughout the thickness of the slab, or the slab may be formed of a surface covering, of sufficient thickness, of bonded fibres parallel to the surface, and a core formed of strips each with the fibres oriented in a plane perpendicular to the surface. Where they overlap the slabs may have grooves 8 in order to reduce the thickness of the overlap. The upper slab may be glued to the lower slab, but may also be fixed by other means, for example pins fixed to the nails, which pins protrude into the end face of the slab.

The wall facing nay be constructed as the roofing or may be constructed as shown with drip caps 9 of metal or plastic sections.

The slabs 3 normally will continue to the underside of the roof, at which point ventilation is unnecessary due to the vapour permeability of the mineral wool facing.

Fig. 2 shows a section through a part of a house with a further internal insulation. On laths 10 a roofing 11 comprising slabs with a tapering profile is fastened for example by gluing. This makes an overlapping at 12 possible in addition to the obtaining of a plane internal - 7 surface 13. An additional insulation 14 therefore may be placed closely adjacent to the roofing slabs without empty spaces, which owing to the air permeability of the mineral wool would tend to reduce the total insulation capacity of roofing and insulation.

Claims (11)

1. CLAIMS :1. A roof or wall that has an external face that is provided by the outer surface of bonded mineral wool elements and that is inclined to the horizontal so that precipitation drains off the external face and in which the fibres of the elements at least in the layer adjacent the outer surface are oriented substantially parallel to that surface.

2. A roof or wall according to claim 1 in which the layer adjacent to the outer surface has a tensile 2 strength of at least 1 kp/cm .

3. A roof or wall according to claim 1 or claim 2 in which the bonded mineral wool elements have an air permea2 bility less than 0.62 m /h mm W.C.

4. A roof or wall according to any of claims 1 to 3 in which the mineral wool elements have a specific weight 3 in excess of 50 kg/m .

5. A roof or wall according to any of claims 1 to 4 in which the bonded agent in the bonded mineral wool elements is hardened phenolic resin.

6. A roof or wall according to any of claims 1 to 4 in which the bonding agent in the mineral wool elements is a latex or acryl modified phenolic resin.

7. A roof or wall according to any of claims 1 to 6 in which the mineral wool elements contain a dye.

8. A roof or wall according to any of claims 1 to 7 in which there is a silicone in at least the surface layer of the mineral wool elements.

9. A roof or wall according to any of claims 1 to 3 in which the external face is provided by the outer face of overlapping or butt joined bonded mineral wool elements , 3 having a specific weight at least 50 kg/m and which are 5 bonded by phenolic resin.

10. A roof or wall according to any preceding claim in which there are indentations for drainage of the precipitation.

11. A roof or wall according to claim 1 substantially 10 as herein described.