A cavity tray

Abstract: The invention relates to a cavity tray (10) for use in a cavity wall, comprising two spaced apart flanges (1, 2) each adapted in use to lie in or adjacent a respective skin of the wall, a connector (3) connecting the two spaced apart flanges, and an arcuate transitional part (4) leading to at least one flange (1 or 2) whereby a super- or sub- posed damp-proof member may be adhered thereto with substantially no discontinuity.

Description: The invention relates to cavity trays, that is pre-formed units that are used in buildings generally to bridge a gap in a cavity wall at say a stop end or change of level. Such cavity trays are usually made from sheet material which is a combination of synthetic rubbers and thermoplastic polymer resins. The trays are intended to facilitate the damp-proofing of awkward junctions and avoid leakage paths, particularly where they are to be combined with a damp-proof course (DPC). The trays and DPC are usually bonded together using adhesive. The problem is that the trays usually have corners or nooks in which it is virtually impossible to lay a damp-proof course, however flexible that course is. The damp-proof course extends from one level to another leaving an unfilled space between it and the cavity tray along which water can pass so that the inner skin of the wall can become damaged. GB-A-2189527 discloses a cavity tray, and EP-A-0243079 also discloses a cavity tray, but neither discloses a curved transition part. It is accordingly an object of the invention to seek to mitigate this disadvantage. According to one aspect of the invention there is provided a cavity tray for use in a double-skin cavity wall, comprising an integral one piece body having two spaced apart flanges lying in planes at different elevations and each arranged in use to lie at least adjacent a respective skin of a wall and a connector intermediate the two flanges and connecting same; characterised by an arcuate transitional part leading from the connector to at least one of the flanges for receiving adhered thereto a damp-proof member whereby there is substantially no discontinuity between the arcuate transitional part and the damp-proof member. The arcuate part is in use adapted to obviate abrupt changes in direction in a direction from one flange to the other. There may be a transitional part of arcuate configuration between each respective flange and the connector. The tray may be made integrally in one piece. One flange may extend in an opposite direction to the other and there may be a member extending at substantially 90° to the plane of the connector and the one flange. One flange may extend in a direction of substantially 90° to the direction of the other flange, and there may be a member extending at substantially 90° to the plane of the connector and the one flange. The member may terminate short of the arcuate part adjacent the other flange. The tray may include a further flange extending a substantially 90° to the plane of the other flange to form therewith an "L"-configuration. The one flange and the connector at least may be in two parts one of which is stepped with respect to the other, and the two parts may be connected by an integral wall member. The other flange may be in two parts one of which may be stepped with respect to the other, the two parts being connected by the integral wall member. The tray may comprise separate components secured together to form an integral unit by a high frequency welding process. The tray may be integrally formed by injection moulding, or by vacuum forming. The cavity tray may be formed from a mouldable composition comprising synthetic rubber and a thermoplastic polymer resin, which may comprise a fibre content. According to a second aspect of the invention, there may be provided a damp-proof system of a structure, comprising a cavity wall, a damp-proof course extending across the cavity from the inner skin to the outer skin over a particular length, and a cavity tray as hereinbefore defined at at least one end of the length of damp-proof course whereby to obviate end leakage of moisture to the skin(s) of the wall. There may be a cavity tray according to any of Claims 1 to 15 at each end of the particular length of damp-proof course. Figs. 1-5 show perspective views from below or behind of various stop end cavity trays according to the invention, Fig. 5 showing a column stop end; Figs. 6 and 7 show from above or in front respectively change of level cavity trays according to the invention; and Figs. 8 and 9 show respectively schematic view of damp-proof course systems incorporating cavity trays of the invention. Referring to Figs. 1-7 of the drawings, in which like parts are referred to by like reference numbers, there are shown cavity trays 10, 20, 30, 40, 50, 60, 70 each of which comprises two spaced apart flanges 1, 2, each flange being adapted in use to be in or adjacent a respective skin of the wall, in the embodiments the flange 1 being for use adjacent the outer skin of the wall and the flange 2 being for use adjacent the inner skin of the wall (not shown). The cavity trays 10-70 each have a connector 3 connecting the two spaced apart flanges 1, 2, and there is an arcuate transitional part 4 leading to at least one flange whereby a super- or sub-posed damp-proof course or member may be adhered thereto with substantially no discontinuity. The transitional part 4 is therefore adapted to obviate abrupt changes in direction in a direction from one flange 1 to the other flange 2, there being an arcuate transitional part 4 between the one flange 1 and the connector 3 and the other flange 2 and the connector 3. Thus in use when cavity tray 10-70 is installed in a cavity wall, a flexible damp-proof course or member in the form of a flexible strip of damp-proof material can be secured to the cavity trays 10-70 by adhesive which is either spread over the cavity trays 10-70 or over the damp-proof course. In either case, the damp-proof course can be laid smoothly in or under the transitional parts 4 so that the cavity trays 10-70 and damp-proof course adhere fully together over their whole overlapping area with no spaces or gaps therebetween, thereby leaving no unfilled space between the cavity trays 10-70 and the damp-proof course. The damp-proof course can be "smoothed" into the curved transitional part 4 to effect this fully adhered union. Moreover, the arcuate transitional parts 4 allow for flexibility or adjustability of the trays 10-70 to allow for variations in skin heights in a wall and over obstructions such as window frames and the like the arcuate parts 4 allowing for a smooth adjustment of the relative dispositions of the first flange 1 and the connector 3 and other flange 2 and the connector 3. Referring now to the embodiment of Figs. 1 to 5, they respectfully show a stop end cavity tray 10, 20, 30, 40 or 50 in which there is a member or end wall of upstand flange 5 which extends at substantially 90° to the plane of the connector 3 and to the plane of the one flange. In Fig. 1 and 2 the end wall 5 is of generally L-shape. In Fig. 1 to 4, the upper (as viewed) edge of the end wall 5 joins the connector 3 just below the start (lower end as viewed) of the radius of upper (as viewed, and as used) arcuate transitional part 4. This is to permit the adjustability already referred to herein, that to allow the flexing or folding of the cavity tray 10-50 about the arcuate transitional partts 4 when it is being installed in a damp-proof system in a cavity wall. In Fig. 5, the end wall 5 extends from the free edge of the one flange 1 to the free edge of the other flange 2, but in this case too the arcuate parts 4 allow flexibility during installation. In Fig. 4 there is an additional flange 2 a upstanding from the other flange 2, on the same side thereof as the end wall 5. In all of the embodiments of Figs. 1 to 5, there is only one end wall 5 welded into the radius 4, so the cavity tray 10-50 is open on side "A" looking into the tray in a direction towards the end wall 5. In the embodiments of Figs. 6 and 7, in which the view is into the tray 60 or 70 from in front and above, the one flange 1 and connector 3 (Fig. 6) or the one flange 1, the connector 3 and the other flange 2 (Fig. 7) are in two parts 1, 1', 2, 2', and 3, 3' which are stepped with respect to one another and are connected by an integral vertical (in use) wall member 6 so as to provide a continuous integral cavity tray 60, 70 which can be used in systems where there is a change of level, for example of brickwork in a par- ticular skin of a wall. Figs. 8 and 9 respectively show use of cavity trays according to the invention in damp-proof systems, the cavity tray being situated at the end of a particular length of damp-proof course 8 in a cavity wall 9, which damp-proof course 8 is received in the cavity tray up to the end wall 5 (Fig. 8) or wall member 6, (Fig. 9). In every embodiment, the cavity tray 10-70 is made as one integral member from components which are secured together as by high frequency welding, or are made by a suitable forming method such as injection moulding or vacuum forming. The material used may be a mouldable synthetic rubber and thermoplastic polymer resin composition. The resin may include a fibre content, for example a mineral fibre.

Claims: A cavity tray for use in a double-skin cavity wall, comprising an integral one piece body having two spaced apart flanges lying in planes at different elevations and each arranged in use to lie at least adjacent a respective skin of a wall and a connector intermediate the two flanges and connecting same; characterised by an arcuate transitional part (4) leading from the connector to at least one of the flanges (1, 2) for receiving adhered thereto a damp-proof member whereby there is substantially no discontinuity between the arcuate transitional part (4) and the damp-proof member. A cavity tray according to Claim 1, characterised in that there is a respective arcuate transitional part (4) between each flange (1, 2) and the connector (3). A cavity tray according to Claim 2, characterised by the two flanges (1, 2) extending in opposite directions and by an end wall member (1) extending at substantially 90° to the plane of the connector and plane of said one flange. A cavity tray according to Claim 3, characterised by the end wall member (5) terminating short of the arcuate transitional part adjacent the other flange. A cavity tray according to any preceding claim, characterised in that an additional flange (2 a ) extends at substantially 90° to the plane of the other flange (2) to form therewith an 'L'-configuration. A cavity tray according to any preceding claim, characterised by the one flange (1) and the connector (3) comprising at least two parts (1, 1', 3, 3'), one of which is stepped with respect to the other, whereby the two parts are connected by an integral wall member (6). A cavity tray according to Claim 6, characterised in that the other flange (2) is in two parts (2, 2') one of which is stepped with respect to the other, and that the two parts (2, 2') are connected by the integral wall member (6). A cavity tray according to any preceding claim, characterised in that there are separate components secured together by a high frequency welding process to form an integral unit. A cavity tray according to any of claims 1 to 8, characterised by being integrally formed by injection moulding, or vacuum forming. A cavity tray according to Claim 8 or Claim 9, characterised by being formed from a mouldable composition comprising synthetic rubber and a thermoplastic polymer resin, preferably by a composition comprising a fibre content. A damp-proof system of a structure, comprising a cavity wall, a damp-proof course extending across the cavity from the inner skin to the outer skin over a particular length, characterised by a cavity tray (10-70) according to any preceding claim at at least one end of the length of damp-proof course whereby to obviate end leakage of moisture to the skin(s) of the wall.

Inventors: BAYES RONALD CURTIS, BAYES, RONALD CURTIS
Applicants: WELDFORM COMPONENTS LTD, WELDFORM COMPONENTS LIMITED
Application year: 1990
Main classification: E04D13
IPC codes: E04B1, E04D13, E04C3