Filed surface and method of application

Abstract

Abstract The invention relates to a cladding panel for a building and a method of attaching such a cladding panel to a building. The cladding panel, made of vitreous silica or a glass having a SiO2 content of greater than 95 percent, is provided with at least one integrally formed projection made of the same material as the rest of the panel, the projection, or each projection having a dove-tailed cross-section in a plane normal to the rear surface of the panel. The method and apparatus further a backing sheet attached to the building and which locks the projection into a keyhole recess formed in the backing sheet to sandwich an adhesive composition between the panel and the sheet. This invention relates to an improved method of attaching facing panels of vitreous silica or high silica content glasses (hereinafter referred to as ''''vitreous facing panel'''') to walls, floors or ceilings and to a composite unit for use on walls, floors or ceilings or as a partition for building purposes. It has already been proposed to attach vitreous facing panels by a method which involves moulding inserts of metal into the vitreous facing panels, the inserts projecting from the rear surface of the panel, and this invention relates to an improved method and to a modified form of panel in which the projecting members are of vitreous silica or high silica content glass. ''''High'''' in connection with the silica content of a glass means, in this specification, greater than 95 percent by weight of SiO2. Vitreous silica is a unique material for the cladding of buildings in view of its unequalled fire and corrosion resistance, the permanent and high quality finish which can be obtained on facing panels and the wide range of textural and colored effects which can be produced. One of the problems which has impeded the large scale acceptance of vitreous silica (and to some extent also the use of high silica content glasses) as a cladding material has been difficulties relating to the securement of the vitreous facing panels on the structure of the building in a secure and foolproof manner using unskilled or, at best, semi-skilled labor. This invention relates to a method of attaching vitreous facing panels to a building structure which is simple to perform and which does result in a fully weatherproofed cladding for the building that meets the most stringent regulations regarding safe securement of facing panels. According to one aspect of the present invention a method of attaching vitreous facing panels to a building structure, each vitreous facing panel comprising at least one portion projecting from the rear surface of the panel, the projecting portion having a dove-tailed cross-section in a plane normal to said rear surface and being integrally formed with the panel, comprises the steps of securing to the structure a backing sheet for each vitreous facing panel, each backing sheet being of a rigid fireproof material and having at least one locking recess or aperture formed therein so that the locking recess or aperture faces away from the structure to which the backing sheet is attached, applying a deformable water-insoluble adhesive material to the sheet at least over the regions against which the panel will lie and pressing the panel onto the backing sheet so that each projectioN thereon passes into a locking recess or aperture and can be locked therein by relative movement of the facing panel to the backing sheet in the plane of the facing panel. In rear elevation, the projecting portion of each facing panel may be circular, oval or polygonal. The number and disposition of the projecting portions on each facing panel depends on the surface area and thickness of the facing panel. Preferably the aggregate surface area of the projecting portions (as viewed normal to the plane of the rear surface) exceeds one per cent of the area of the rear surface and the separation between projecting portions (measured in the plane of said rear surface between centers) is less than two feet. The backing sheet (conveniently a sheet of asbestos board) is conveniently provided with one ''''keyhole recess or aperture'''' (as hereinafter defined) for each projecting portion, at least the retaining slot of the keyhole recess or aperture being chamfered on the side away from the panel to mate with the chamfered edge of the dovetail projection. The backing sheet (with the correct number and relative disposition of keyhole recesses or apertures to accommodate a particular vitreous facing panel) is fixed in place by any conventional fixing member (e.g. non-corrosive bolts or screws) and is then coated with the resilient adhesive (which may or may not be of the hardening variety) at least over the regions against which the peripheral edges of the panel will lie. The vitreous facing panel is then secured in place by engaging the projecting portions of the panel in the keyhole recesses or apertures of the backing sheet and sliding the panel on the backing sheet to accommodate the projections in the retaining slots of the keyhole recesses or apertures. During the panelsecuring operation, the adhesive is compressed between the panel and the backing sheet and remains sandwiched therebetween to form a watertight seal. A hydrophobic oil-based mastic composition is the preferred adhesive but a hydraulic cement can also be used. Throughout this specification by a ''''keyhole recess or aperture'''' we mean a recess or aperture having an enlarged opening at one end of a retaining slot, the opening being dimensioned for the insertion of the projecting portion therein in the direction normal to the plane of said one surface of the panel while the retaining slot allows the projecting portion to slide therealong, if the outer wider end of the projecting portion is located in the slot, but will not allow the projecting portion to be withdrawn from the retaining slot in the direction normal to said one surface of the panel. The projecting portion or portions is or are conveniently formed from blocks of vitreous material in a first fusing operation and the shaped blocks are then integrally fused into a sheet of vitreous silica or high silica content glass when the panel is formed, temperature conditions during the formation of the panel being controlled to ensure that the dove-tailed projecting portion or portions do not distort. Thus, for example, the panels can be formed in shallow graphite trays having recesses therein to receive the projecting portions of the pre-formed blockS, the tray being filled with silica sand (normally containing traces of one or more suitable coloring additives) to cover the blocks. The sand, and just those regions of the blocks embedded in the sand, are then fused in a second operation to form a vitreous facing panel integral with the projecting portions. A facing panel of pure vitreous silica having at least one portion projecting from the rear surface of the panel, the projecting portion having a dove-tailed cross-section in a plane normal to said one surface, and being integrally formed with the panel, constitutes a further aspect of the invention. A composite unit which comprises a vitreous facing panel attached to a backing sheet with a layer of adhesive sealing the gap between the paNel and the sheet, at least around the periphery of the former, constitutes a further aspect of the invention. Normally a plurality of backing sheets will be placed side by side to form a substantially planar surface on which the vitreous facing panels will be secured (typically we make the backing sheets of the same shape and area as the facing panels). The joins between the adjacent backing sheets can then be covered with an adhesive sealing strip of waterproof character (e.g. a metal foil coated with a hydrophobic pressure-sensitive adhesive).

Inventors

• 👤 Frederick James Edwards

Bibliographic Details