EXTERIOR, WATER-REPELLANT FACING OR COVERING FOR BUILDINGS

Abstract: Exterior, water-repellant facing or covering for buildings for example for roofs or walls mounted in the shape of plates or slabs with overlaps or butt joints on a support with a gradient for drain of rainwater. In order to eliminate the risk of condensation on the internal face of the support and at the same time reduce the transmission of heat through the covered wall or roof the roofing or facing consists of mineral wool containing a bonding agent, in which mineral wool the direction of the fibers is substantially perpendicular to the external surface.

Description: Exterior, water-repellant facing or covering for buildings. The present invention relates to an exterior, water-repellant facing or covering for buildings for example for roofs or walls in the shape of plates or slabs mounted with overlaps or butt joints on a support with a gradient for drain of rainwater. Facings or coverings of this type are normally made from af hard and compact materials, which are impervious to rain and substantially airtight. Preferred materials are metal, tile, or asbestos cement. These materials present some drawbacks if an insulating layer, is not provided, which is able to prevent a large heat transmission or to prevent condensation of humidity on the inside surface of the facing or covering. In storehouses, garages and similar unheated buildings of a simple construction with walls comprising only the layer giving protection against the precipitation condensation of humidity may involve considerable problems, and dripping of condensate may cause serious damage to goods or machinery stored in the building. The object of the present invention is to provide an exterior facing or covering of the type according to the preamble, in which facing or covering the above drawbacks are eliminated. According to the invention this object is obtained with a covering or facing which is characterised in that it consists of mineral wool containing a bonding agent, in which mineral wool the direction of the fibers is substantially perpendicular to the external surface. The invention is based on the observation that mineral wool containing a bonding agent and with the fibers substatially perpendicular to the surface of the mineral wool is repellant to rain and other precipitation. If the fibres are orientated substantially perpendicular to the outer surface of the mineral wool the covering or facing may be considered to be made from tranverse- oriented mineral wool, and in this position the mineral wool is very resistant to the influence of weathering. The exterior surface may weather in a thickness of a few millimeters, but inside this surface layer the mineral wool will remain intact and preserve its properties, because it is protected by means of the weathered surface layer. As the mineral wool on the other hand is porous and therefor permeable to air and vapour, a condensation cannot take place r and the abovementioned drawbacks of known facings are eliminated. As a consequence it is for example possible to construct a massive covering without a ventilation of the inside of the covering and of for example rafters and battens, which means that the covering or the facing may be included in the insulation of the building. This property also makes the covering impermeable to snow, because there are no ventilated cavities into which the snow may penetrate. The covering as such is also impermeable to snow, as it is possible to construct sealed joints for example by cementing or glueing the joints. Due to the elasticity of the mineral wool there is no need for a plastic joint filler. As the mineral wool further is a poor conductor of heat good insulation properties of the building is obtained. Transverse-oriented mineral wool, the fibres of which preferably are oriented perpendicular to the surface compared with normal mineral wool, the fibres of which are oriented in planes parallel with the surface layer, provides a stronger and more weatherproof surface. The tranverse-oriented mineral wool may be produced from mineral fibres, which are collected on a perforeated band at the end of a spinning chamber, in which a hardenable bonding agent is atomized. The bonding agent may be a phenolc resin, for example phenol formaldehyde resin, but also flexible forms of phenolic resins, such as latex- or acryl- odified phenolic resins, may be used, as these resins are better suited to withstand the impact from hails or other objects that may hit the facing or covering. The layer of mineral fibres thereafter is compressed and the bonding agent is hardened at the same time and an endless web is formed. The compression should have such an extent that the density of the mineral wool 3 exceeds 50 kg/m , but in most cases a density exceeding 3 100 kg/m is preferable. According to a preferred embodiment the endless web is cut longitudinally or transversally at distances corresponding to the final thickness of the layer of transverse-oriented mineral wool. The cut-off strips or lamellae are rotated or turned 90°, and the fibres are thereafter have an orientation, which is mainly perpendicular to the new surface. It is known that the resistance to compression forces increases;in tranverse-orientated fibres, as the compression forces are transmitted from the ends of the fibres along the fibres into the body of the mineral wool instead of being transferred by deflection of the fibres as it happens in normal mineral wool products, in which the fibres are orientated substantially parallel with the surfaces of the product. Another and more important advantage of using the tranverse-oriented mineral wool products is an improved protection of the bonding of the fibres at their intersections against the ultraviolet rays from the sun. In practice it has been proved, that unprotected mineral wool products with transverse-oriented fibres have an improved durability and reduces the pollution with fibres to the environment compared with normal, unprotected fibre products. The invention is further described in the following specification with reference to the drawing, in which examples of building constructions including the exterior facing or covering according to the invention is used. Fig. 1 shows part of a building, roof or wall, which part on the outside surface is covered by an insulation layer comprising mineral wool slabs with transverse-oriented fibres. Fig. 2 shows an insulation element in which mineral wool with transverse-oriented fibres is mounted on a base consisting of normal mineral wool. In fig. 1 a roof or a wall 2 is shown. The Wall 2 may be a concrete wall, a wooden wall or any other kind of wall, it is however preferable that its outer surface is comparatively smooth. The wall 2 is insulated on the outside by means of a prefabricated element l r which glued or cemented to the wall 2 by means of a cement or adhesive 3. The element 1 is amanufactured by glueing together a number of lamellae 5 in the joints 4. The element may also/or further be reinforced by a more or less thin web 6 for example 1 a glass fibre fleece 6 or annother form of support. The insulation 1 may also be produced by glueing separate lamellae 5 on the wall in situ. In fig. 2 another embodiment in which a prefabricated element 1 is mounted on purlins 7. The element 1 is made from lamellae 5 consisting of mineral wool with tranverse-oriented fibres, which by means of an adhesive or a glue 8 have been mounted on a support comprising for example a normal slab 9 of mineral wool. As the the resistance to compression of a surface of transverse-oriented mineral wool with a densitiy af 100 kg/m is comparable with the reεistande to compression of 3 normal mineral wool with a density of 200 kg/m , it is seen that in order to obtain a specific resistance to compression 50% of the mineral fibres may be saved. On the other hand the insulating properties of tranverse-oriented mineral wool is 15% inferior to normal mineral wool with the same density. The saving by using mineral wool with transverse-oriented fibres for covering of facings therefore is 35% plus the advantage of higher resistance to erosion. When a building construction in consideration of the internal climate also comprise an airtight or vapour impermeable membrane, it should placed directly on the inside surface of the insulation. The airtight or vapour- impermeable layer may be sprayed or glued on the back of the insulation. The water-reppellant properties of transverse- oriented mineral wool is normally sufficient for ensuring a precipitation-proof roofing if the inclination of the facing or roofing is larger than 30 -40 . If the inclination of the roof is smaller it is preferable to include a watertight membrane in order to prevent undesired penetration of water, and this mambrane may in some cases also serve as a vapour-impermeable membrane. The mineral wool for the insulation preferably has 3 a density of at least 50 kg/m and in many cases a density of 100 kg/m is preferable. It is possible to compress the slabs to ar larger extent and possibly laminate the slabs in order to increase the strength to be sufficient to withstand an increased distance between the supports. The mineral wool may be dyed during its manufacture with a suitable pigment, or the facing or roofing may be painted after it has been mounted. It is also possible during the manufacture to use raw materials giving dark or possibly black fibres. The properties of the mineral wool may be improve by means of silicone in order to further reduce the rate of erosion, which depending on the climatic cnditions amounts to a fraction of a millimeter per year. During the manufacture of the lamellae of tranverse-oriented mineral wool the knife, saw-blade or cuttng jet is preferably moved in a direction, which is perpendicular to the surface of the web of produced mineral wool. The lamellae may also be produced from stock goods, i.e. mineral wool products which have been cut into slabs and thereafter stored.

Claims: Claims : 1. Exterior, water-repellant facing or covering for buildings for example for roofs or walls mounted in the shape of plates or slabs with overlaps or butt joints on a support with a gradient for drain of rainwater, c h a r a c t e r i z e d i n that it consists of mineral wool containing a bonding agent, in which mineral wool the direction of the fibers is substatially perpendicular to the external surface. 2. Facing or covering according to claim 1, c h a r a c t e r i z i n g i n that the bonding agent is a phenol formaldehyde resin. 3. Facing or roofing according to claim 1, c h a r a c t e r i z e d i n that the bonding agent is a latex- or acryl-modified phenolic resin, 4. Facing or roofing according to claim 1, 2, or 3, c h a r a c t e r i z e d in that the covering comprises closely juxtaposed lamellae, which have been cut with a distance between the cuts corresponding to the thickness of the covering, and which before being juxtaposed is rotated 90° obout their axis.

Inventors: SKJOLD PETERSEN JOERGEN, SKJOLD PETERSEN, JOERGEN
Applicants: ROCKWOOL INT, ROCKWOOL INTERNATIONAL A/S
Application year: 1988
Main classification: E04D3
IPC codes: E04B1, E04D3, E04D13, E04F13