IE46831B1

IE46831B1 - Improvements in or relating to facings

Info

Publication number: IE46831B1
Application number: IE1025/78A
Authority: IE
Original assignee: Perm U Board Ltd
Priority date: 1977-05-28
Filing date: 1978-05-23
Publication date: 1983-10-05
Also published as: GB1594353A; IE781025L; DE2822744A1; FR2392194A1

Abstract

Facing to be fixed later on on a wall or a ceiling, comprising a panel of an expanded plastic and its manufactoring process. A composite plasters/plastic recovers the two faces and the edges. [FR2392194A1]

Description

The present invention concerns facings for attachment to walls and ceilings.

The traditional way of finishing walls and ceilings was wet plastering which had considerable advantages in that plaster is a reasonable thermal insulant and tended to absorb any condensation without showing signs of dampness whilst at the same time it is fireproof. However wet plastering required great skill on site and was time consuming. The modern technique known as dry-lining seeks to reduce site work and involves attaching facings to the walls and ceilings either by an adhesive or by nailing to battens. To avoid problems in condensation and waste of heat, the facings should not abstract heat from a room but should be a thermal insulator. Ά good thermal insulant is foamed plastics material such as foamed polystyrene but there are serious problems. An exposed face of such a facing is easily damaged and would support the spread of flame across it with the risk of falling burning molten plastics material'and noxious fumes. It has been suggested to covers foamed plastics material with. plaster,to protect and render fire-proof the material. However this had to be done on site since a foamed plastics material in the thicknesses used for facings distorts under the strains set up when the covering sets unless the foamed plastics material is supported firmly over its entire area as by being bonded to a wall.

'.Moreover even if it were possible to precover a facing, the foamed plastics material would not add stiffness to the covering and transport and handling of a facing would be virtually like handling a sheet of plaster which due to its brittleness - 2 4 6 8 31 would, tend to crack and flake away from the underlying foamed plastics material. However even site-covered plastics material facings do not eliminate the fire hazard. In a fire the plaster gets hot and the foamed plastics material collapses shrinking away from the hot plaster and leaving the covering unsupported with an air passage behind it. Even if the unsupported plaster does not flake away, air can get to the collapsed plastics material. For this reason sufficient plaster is needed to prevent heat reaching the foamed plastics material.

Materials known as plastic compounds are sold as finishing and texturing coatings usually under a trademark ending in TEX (such as ABTEX supplied by Gypsum Industries ltd.). They are water-based compositions formulated so as to be relatively slow setting to allow the coating to be moulded, textured or otherwise worked and generally comprise chalk, gypsum, glue and additives. Like plasters, they set at room temperature, and when set do not soften with heat, are fire-resistant, and are immune from attack by water- and oil-based paints. They are slightly more flexible and easier to cut without excessive chipping than plasters and shrink less when setting. When using these plastic compounds, the wall or ceiling is given dabs or a bed of the plastic compound, and expanded plastics material facings are bedded down on the plastic compound. The edges of the facings are normally closely abutted. Any excess plastic compound extruded through the fine gaps is wiped off. After the plastic compound sets, a coat of plastic compound is used to finish the installation. The facings thus form a sheet of foamed plastics material covering the wall or ceiling with at most a very thin layer of plastic compound bonding the edges of the facings together which thin layer can be ignored for all practical purposes. - 3 4 (5 8 3 1 The present invention provides a facing for subsequent attachment to a wall or ceiling comprising a panel of expanded plastics material having on both faces a plastic compound coat containing a reinforcing layer and having plastic compound on the 5 edges.

The plastic compound on the edges serves to space the facings' foamed plastics material apart forming a type of honey comb. If heat causes the collapse of the foamed plastics material, the residues are trapped in the cells of the honey comb with the walls of the cells forming fire dams preventing an air flow through the space previously occupied by the foamed plastics material. l-Zhilst it would be possible to have the edges of the facings with only beads of the plastic compound on them to act as spacers and to grout the gaps between facings, it is preferred to have the edges completely coated as in this way the facings can be nailed to battens if desired. However bedding the facings on plastic compound and grouting the gaps is preferred in any event since not only is it cheaper but the grouting reinforces the plastic compound on the edges.

The facings can be coated on.both faces simultaneously by passing the panels of expanded plastics material on edge (i.e. with the panels vertical and supported on an edge) through suitable stations.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which :Figure 1 is a schematic section through a tile size facing according to 3ritish Patent No. 1 5?0 218, Figure 2 is a schematic section through a larger facing according to the present invention, and - 4 46831 Figure 3 is a schematic plan view of apparatus for coating both sides of an expanded plastics material panel.

The facing of Figure 1 is of tile size, say 9inch square (250 millimetre square) of an expanded plastics material 11 preferably of closed cell structure such as foamed polystyrene coated on both major faces and on the edges by a plastic compound 12 which can he applied hy dipping in a wet thick-cream consistency of the plastic compound or spraying. The coating on the face intended to he the visible face is built up by a subsequent application 14 of further plastic compound which can be extended by the use of fillers if desired. Such facing will tend to be relatively thin, say i inch (7 mm.) and may have chamfered edges. The facing of Figure 2 is a development for larger size panels. A panel 16 of an expanded plastics material such as foamed polystyrene, say 8 hy 3 foot (2500 hy 900 mm) and between £ and 1 inch thick (14 to 26 mm.) is coated on both faces and all the edges with a plastic compound coat 17, then a reinforcement layer 18 is bedded onto or into the coat 17 on each face, and finally a further coat 19 of plastic compound is applied to at least the faces hut preferably to the edges as well.

The plastic compound coats can all be allowed to set simultaneously but it is possible to allow the coat 17 to set before the coat 19 is applied. The reinforcement layer 18 can he of paper and can include a vapour barrier. However it is preferred to use as a reinforcement a material which hy itself is flame resistant, does not degrade with heat especially if such degradation results in the emission of gas which might hurst the plastic compound, and which if the protecting plastic compound cracks does not oxidise but preserves its integrity. Such a material is fibre glass; a single layer of 0.030 inch (.7 mm.) with large diameter filaments is used in this embodiment. Such a fibre glass reinforcement - 5 4 68 31 not only provides mechanical strength hut resists accidental abrasions cutting through the layer 19 and the reinforcement. The facing can. still he cut and so is not vandal-proof· hut in a normal household with the wall under the eye of the tenant and normally covered, with the usual wall-paper, the risk is of a piece of furniture being bumped against the wall and this will not severely damage the facing.

Generally facings of foamed polystyrene corresponding to the panels of the present invention are clean cut and. tradesmen io take pride in the closeness of their joints. The present invention deliberately spaces the panels apart so creating the all important small walls of plastic compound separating the panels. If the panels are merely spaced by beads of the plastic compound on the edges, there might be a tendency for tradesmen to chip off these beads to get the desired close joints; thus it is better to have a complete smooth coating on the edges even apart from the cases where the facings are not to be bedded in plastic compound but nailed in place. The Warrington Hesearch Centre has carried out tests for compliance with 2o British Standard 476 as a result of which a panel as described in relation to Figure 2 meets the requirements of the Class 0 of the British National Building Regulations and achieved a Class d Surface Spread of Flame rating.

As stated facings according to the present invention can be cut, by a knife or a fine saw, to restore the fire proofing the cut edges should be coated twice with plastic compound. Thus facings according to the present invention can be cut and pieced into comers without impairing their - 6 40831 flame proof ratings.

Figure 3 shows schematically apparatus for making wall facings comprising a first set of feed rollers 20 for feeding panels of foamed polystyrene supported on a long edge 5 through a first plastic compound spraying station 21 comprising spray heads 22 disposed to as to spray the plastic compound on both faces in even coats, through a laminating station 23 wherein glass fibre reinforcement is taken from a spool 2A on each side of the panel and is laid into the previously sprayed compound by a roller 25 engaging each face, through a finishing spray station 26 where a further plastic compound coat is applied to both faces, through rollers 27 to spread the compound along top and bottom edges, and into a stepping storage rack 28 wherein the compound is allowed to set. The leading and trailing edges of each panel will be coated as they pass through the spraying stations. A known parting knife would be used - to part the fibre glass between the facings before the facings are received in the rack. The use of sprays enables a coating to be applied in a thick stiff consistency so that the compound will not tend to run and will not mark excessively by contact with the rack; polystyrene is only light as are the facings so that there will not be much force on the coating. The thickness of the edge coating should be sufficient for the set compound to form a self-supporting box even when the support given by the polystyrene is ignored. It will however be appreciated that even with aR edge coating of say 0.040 inches (1 mm), when two facings abut and are grouted together there will be a fire dam of 0.080 inches (2 mm)· 6 3 31 The honey comb cells with 8' x 5' panels may be thought rather large for mechanical strength by some customers and intermediate support can be provided by plastic compound extending between both faces through perforations in the panels. - 8 46631

Claims

1. CLAIMS:- . .»

1. A facing for subsequent attachment to a wail or ceiling comprising a panel of expanded plastics material having on both faces a plastic compound coat containing a reinforcing layer and having plastic compound on the edges.

2. A facing according to claim 1 wherein the reinforcement is glass fibre.

3. A facing according to claim 1 or claim 2 wherein the plastic compound on the edges forms a complete coating on the edges.

4. A facing for subsequent attachment to a wall or ceiling substantially as herein described with reference to Figure 2 of the accompanying drawings.

5. Apparatus for producing a facing for subsequent attachment to a wall or ceiling comprising a device for feeding foamed plastics material panels on edge through a spraying station wherein a first coating of plastic compound is to he applied, a laminating station wherein a layer of reinforcement is applied to both faces, and a second spray station wherein a further coating of the plastic compound is applied and into a storage rack wherein the plastic compound can set.

6. Apparatus substantially as herein described with reference to Figure 3 of the accompanying drawings.

7. A method of producing a facing for subsequent attachment to a wall or ceiling substantially as herein described with reference to Figure 3 of the accompanying drawings. F. R. KELLY & CO., AGENTS FOR THE APPLICANTS. - 9 LESLIE RAYMOND BACK