GB2215359A - Damp proof courses for corners of cavity walls - Google Patents

Abstract

A corner element for a damp-proof course is formed from a blank comprising two inversely congruent halves 1, 2, each having a base portion 3, 4, a cavity bridging portion 5, 6 joined to the base by a fold line 7, 8 and a triangular gusset 15, 16 extending along one side 17, 18 of the bridging portion and having an apex situated at the intersection of that side 17, 18 and the fold line 7, 8. The blank is assembled by superimposing one half 1 on the other 2 with the fold lines 7, 8 at right angles and the apices coinciding, and sealing together the overlapping areas of the bases 3, 4. <IMAGE>

Description

IMPROVEMENTS IN DAMP PROOF COURSES The present invention relates to damp proofing of buildings, and specifically concerns a cavity spanning damp proofing element for use at internal and external corners of an abutment.

Where an exterior wall has a roof extending outwardly from a point below its top, such as may occur at a garage extension for example, the external wall passes below the roofline of the extension to become an internal wall. To prevent moisture incident on the outside wall percolating down into the interior, a damp proof course must be installed above the roofline to direct water out on to the roof. The damp proof course must also span the cavity if the wall is a cavity wall, so that water cannot run down the faces of the cavity and thus penetrate into the internal walls of the building.

Prior attempts to provide a rapid and durable damp proof element have led to the fabrication of rigid pre-formed corner units of plastics material, but a drawback with these is their inability to cope with more than one cavity width, thus necessitating the stocking of a large number of different size units. Another problem with these rigid units is their bulk, which makes storage and transportation expensive.

In our copending application No. 87.26609, a cavity tray for use at sloping or horizontal abutments is described, and the present invention provides internal and external corner units complementary to the cavity tray, in use.

According to the present invention, a blank for a cavity spanning corner element for a damp proof course comprises two inversely congruent halves formed of an impervious foldable sheet material, each half comprising an elongate rectangular base portion, a bridging portion extending laterally from the base portion, and joined thereto at a fold line, each half further comprising a triangular gusset, the gusset having one of its apices at the intersection of a side of the bridging portion and the fold line, and the gusset extending along the side of the bridging portion, the halves being assembled together with the said fold lines directed at 900 to each other, the said one apex of each gusset coinciding with the one apex of the other gusset, and their bases at least partially overlapping and sealingly attached to one another.Preferably, each half has a fixing strip extending along the edge of the gusset opposite the bridging portion, and a sealing lip extending along the edge of the bridging portion opposite the base.

Two embodiments of the present invention will now be described in detail, with reference to the accompanying drawings, in which: Figure 1 shows two halves of an internal corner element, prior to assembly into a blank; Figure 2 shows the internal corner element blank assembled from the halves shown in Figure 1; Figure 3 is a perspective view of the internal corner element in its final configuration ready for use; Figure 4, shows two halves of an external corner element, prior to assembly into a blank; Figure 5 shows the two halves of Figure 4 assembled to form an external corner element blank; and Figure 6 is a perpective view of the external corner element blank folded into its final configuration ready for use.

Referring to Figure 1, the corner element blank comprises two mirror-image halves 1, 2 each of which comprises a generally rectangular base portion 3, 4, which will lie in use horizontally between two courses of bricks or building blocks of the outer skin of a cavity wall, and a trapezoidal cavity bridging portion 5, 6 extending from one longer side of the rectangular base 3, 4, a fold line 7, 8 marking the boundary.

The trapezoidal bridging portions 5, 6 have one side 9, 10 collinear with a side of the base 3, 4, and a third side 11, 12 parallel to but longer than the fold 7, 8. Extending along the edge of the bridging portion 5, 6, opposite its base portion 3, 4 is a sealing lip 13, 14 which in use either lies against or is built into the inner leaf of the cavity wall.

Each half 1, 2 is further provided with a triangular gusset 15, 16 extending from the inclined edge 17, 18 of the bridging portion 5, 6. The gusset is divided into two zones, 19, 20, 21, 22 separated by a fold line 23, 24 which intersects the apex of the gusset 15, 16 adjacent the base 3, 4. A fixing flange 25, 26 is attached to the side of the gusset 15, 16 and will be explained in detail later.

To assemble the halves 1, 2 into a blank, one half 2 is rotated buy 900 relative to the other half 1, and is placed so that the apices of the gussets 15, 16 adjacent the base 3, 4 of each respective half are superimposed, and the base 4 of half 2 partially overlies the base 3 of half 1, as may be seen from Figure 2.

The overlapping area of the bases 3, 4 is secured by mastic or other sealant or adhesive interposed between the bases 3, 4. The underside of fixing flange 26 and the upper face of fixing flange 25 as seen in Figure 2 are then given a coating of a pressure-activated sealant or adhesive and this coating is covered by a release liner such as a peel-off backing. The blank is then ready for use.

In order to form the blank into a corner sealing element, the cavity width must first be ascertained. The configuration of the gussets 15, 16 in two zones 19, 20, 21, 22 provides three fold lines between the bridging portion 5, 6 and the fixing flange 25, 26, and each fold line corresponds to a predetermined cavity width.

In the illustrated case, fold lines 17 and 18 are used when the cavity width is least, say 50 mm, fold lines 23 and 24 are used when the cavity width is intermediate, say 75 mm, and fold lines 27 and 28 are used when the largest cavity width must be spanned, say 100 mm.

Figure 3 shows the blank folded to form a corner sealing element for a small cavity. To fold the blank to this configuration, the gusset 16 is folded up about fold line 18, and bridging portion 6 is folded up about fold line 8. Gusset 15 of bridging portion 5 is then folded up about fold line 17, and bridging portion 5 folded up about fold line 7, until the gusset 16 of half 2 contacts the bridging portion 5 of half 1 on its upper face (as seen in Figure 2) and the gusset 15 of half 1 lies behind (as seen in Figure 3) and in contact with the bridging portion 6 of half 1.

Having ascertained that this is the correct configuration by testing in situ, the release lining on the mastic or adhesive on the fixing flanges 25, 26 may be removed and the blank secured in the final configuration by bonding the fixing flanges 25, 26 in position respectively on the rear face of bridging portion 6 and the front face of bridging portion 5 (as seen in Figure 3).

The blank may be advantageously provided with a separate small patch (not shown) intended to be applied into the apex formed by the bases 3, 4 and bridging portions 5, 6 to prevent any leakage that may otherwise occur at this apex.

Referring now to Figure 4, there is shown a pair of halves 101, 102 for assembly into a blank for an external corner sealing element, in a manner analogous to that described above.

Each half 101, 102 comprises a base portion 103, 104 which, in use, is situated between two horizontal courses of blocks in the outer skin of a cavity wall. A bridging portion 105, 106 extends from each base portion 103, 104, with a fold line 107, 108 forming the boundary. The bridging portions 105, 106 are trapezoidal but taper away from the base portions 103, 104, and each bridging portion has a sealing lip 113, 114 extending from its edge parallel to the fold line 107, 108.

As may be readily seen, the base portions 103, 104 extend lengthwise beyond the bridging portions 105, 106. Adjoining on inclined edge 117, 118 of the bridging portions 105, 106 are respective gussets 115, 116 each divided into two zones 119, 120, 121, 122 by a central fold line 123, 124 meeting the respective inclined edge 117, 118 at its point of intersection with fold line 107, 108.

On the side of the gusset remote from the bridging portion, a fixing flange 125, 126 extends as will be described below.

To form the halves into a blank, the half 102 is rotated clockwise through 900, and is then offered up to half 101 so that the overhung end of base portion 104 underlies the end of base portion 103, but the bridging portion 106 overlies the bridging portion 105. While this is different from the superposition of the halves of the internal corner blank, it is forseen that the internal blank may be made by arranging the base 3 of half 1 to underlie the base 4 of half 2 and the fixing flange 25 of half 1 to overlie the bridging portion 6 of half 2. Equally, the halves 103, 104 of the external corner blank may be arranged so that the half 101 overlies half 102 at all points, i.e. base 103 overlies base 104, and bridging portion 105 overlies bridging portion 106.

The bases 103, 104 are fastened and sealed with adhesive or mastic, as before, and the fixing flanges 125, 126 have a coating of mastic or adhesive sealant on their upper and lower faces as seen in Figure 5.

The blank is assembled to form a corner element by a folding process analogous to that described in relation to the internal corner element, in that the appropriate fold line is selected from the three available gussets to suit the cavity width, folds 117, 118 for the widest cavity and folds 127, 128 for the narrowest, and the bridging portions 106, 105 are raised by folding about lines 108 and 107 respectively. Gusset 116 is then folded and secured to bridging portion 105 by the fixing flange 126, and gusset 115 is fixed to the bridging portion 106 by fixing flange 125, to achieve the external corner element seen in Figure 6 folded for a wide cavity. As previously described, a sealing patch (not shown) may be applied to the apex at the intersection of fold lines 107 and 108 to avoid any leakage.

Claims (10)

1. A blank for a cavity-spanning corner element for a damp proof course, comprising two inversely congruent halves formed of an impervious foldable sheet material, each half comprising an elongate rectangular base portion, a bridging portion extending laterally from the base portion, and joined thereto at a fold line, each half further comprising a triangular gusset, the gusset having one of its apices at the intersection of a side of the bridging portion and the fold line, and the gusset extending along the side of the bridging portion, the halves being assembled together with the said fold lines directed at 900 to each other, the said one apex of each gusset coinciding with the one apex of the other gusset, and their bases at least partially overlapping and sealingly attached to one another.

2. A blank according to Claim 1, wherein each half of the blank has a fixing strip extending along the edge of the gusset opposite the bridging portion.

3. A blank according to Claim 1 or Claim 2, wherein each half of the blank has a sealing lip extending along the edge of the bridging portion opposite to the said fold line.

4. A blank according to any preceding claim, wherein the gusset of each blank half includes a plurality of fold lines extending from the said apex across the gusset, dividing the gusset into a plurality of triangular zones.

5. A blank according to any preceding claim, wherein the bridging portion is trapezoidal and adjoins the base along the longer of its parallel sides, and the said apex is situated intermediate the length of the base.

6. A blank according to Claim 5, wherein first and second inversely congruent blank halves are assembled by having a part of the base of a first blank half overlying, and sealingly attached to, a part of the base of the second blank half, while the bridging portion of the second blank half substantially overlies the bridging portion of the first blank half.

7. A blank according to any of Claims 1 to 4, wherein the bridging portion is trapezoidal, and adjoins the base along the shorter of its parallel sides, and the said apex is situated at a corner of the base.

8. A cavity spanning corner element formed from a blank according to any preceding claim.

9. A cavity spanning corner element substantially as herein described with reference to Figures 1, 2, 4, or 5 of the accompanying drawings.

10. A cavity spanning corner element substantially as herein described and illustrated in Figure 3 or Figure 6 of the accompanying drawings.