GB2221934A

GB2221934A - Coping for a cavity wall

Info

Publication number: GB2221934A
Application number: GB8915249A
Authority: GB
Inventors: Denis Carling
Original assignee: Ibstock Building Products Ltd
Current assignee: Ibstock Building Products Ltd
Priority date: 1988-07-02
Filing date: 1989-07-03
Publication date: 1990-02-21
Also published as: GB8915249D0; GB8815786D0

Abstract

The leaves 11, 12 of a cavity wall 10 each have a respective row of coping blocks 14, 15 along their tops, the leaf 11 being one course higher than the leaf 12 so that the blocks 14, 15 can overlap horizontally. A compressible strip 23 e.g. made of polyethylene is secured between the overlapping portions of the blocks 14, 15 to allow for differential expansion of the two leaves 11, 12. The strip 23 can however be replaced by a simple air gap. <IMAGE>

Description

Title: Coping or Capping System for a Cavity Wall.

This invention relates to a coping or capping system for a cavity wall.

According to the invention, such a coping or capping system comprises a series of first block members mounted on a first leaf of the wall and extending in a row longitudinally of the wall, a series of second block members mounted on a second leaf of the wall and extending in a row longitudinally of the wall, the first members having first surfaces which confront adjacent second surfaces on the second block members, there being no rigid connection between the first and second surfaces.

Preferably, the first block members partially overlap the second block members, and the first and second surfaces are disposed in the area of the overlap. The first and second surfaces are desirably horizontal or substantially so.

Conveniently, each second block member has an upstanding ridge on its upper surface, and the respective second surface is formed by a surface of the ridge. In this case, each first block member may have a depending rib on its lower surface, with the ribs on the first block members being disposed on a side of the ridges on the second block members opposite to the first leaf, and the ribs vertically overlapping the ridges.

Each second block member may have depending ribs on its lower surface which locate on either side of the second leaf.

Advantageously, the first block members are staggered relative to the seond block members along the length of the wall.

The non-rigid connection between the first and second surfaces can be formed by an air gap or by a compressible member. In the latter case, the member is preferably in the form of a strip and is preferably also made of a resilient material, which may be a plastics material such as polyethylene.

The invention wil now be described, by way of example only, with reference to the accompanying drawing which is a setional perspective view of a coping system according to the invention. In the drawing, there is shown a cavity wall 10 comprising two brick-built leaves 11 and 12 surmounted by a coping system 13, the leaf 11 being one course higher than the leaf 12. The coping system 13 includes a series of first extruded block members 14 mortared to the top of the leaf 11, and a further series of second extruded block members 15 mortared to the top of the leaf 12. Each series of block members thus extends in a row longitudinally of the wall. Each block member 14,15 has a length equal to that of a standard brick (although other lengths are possible), and the blocks are staggered along the length of the wall 10 relative to the bricks in the topmost course of the respective leaf.The members 14 and 15 are thus themselves mutually staggered along the length of the wall, and their upper surfaces form water-displacement surfaces for the system.

Each block 15 has at one side thereof a portion 16 which extends to the cavity and which has a depending rib 17 on its underside and an upstanding ridge 18 on its upper surface, the rib 17 and the ridge 18 both extending parallel to the longitudinal direction of the wall 10.

Each block 15 also has at the other side thereof a further depending rib 19, the spacing between the ribs 17 and 19 being slightly greater than the width of the leaf 12 so that the ribs locate on either side of the latter, there being a vertical overlap between each of the ribs 17 and 19 and the top course of bricks in the leaf 12.

Each block 14 has at one side thereof a portion 20 which extends across the cavity and which overlies the portions 16 of the adjacent blocks 15. The portion 20 terminates in a depending rib 21 which extends in the longitudinal direction of the wall 10 and which locates on the opposite side of the ridges 18 to the leaf 11, there being a degree of vertical overlap between the rib 21 and those ridges 18. At its opposite side, each block 14 has a further depending rib 22 which vertically overlaps the top course of bricks in the leaf 11.

The blocks 14 and 15 thus confront one another along first surfaces on the undersides of the portions 20 and along second surfaces on the top of the ridges 18, these surfaces being closesly adjacent to each other. A non-rigid connection is provided between these surfaces: in the illustrated embodiment, this is formed by a flexible strip member 23 made of compressible material which is engaged between the surfaces, however, an air gap would suffice instead.The function of the strip member 23 is to act as a compressible filler to prevent rigid material (such as mortar or brick debris) from becoming trapped between the upper surface of the ridges 18 and the undersurface of the block portions 20. f these two surfaces move closer together due to a differential expansion of the two leaves 11 and 12, such trapped material could otherwise induce stresses in the coping system and cause cracking. The strip member 23 can be made of any suitable material, and is preferably a compressible material suitable for use as a movement joint filler as described in BS5628 Part 3 1985 (clause 20.4, page 35).

Such a material can be a resilient plastics material such as polyethylene.

In order to enable the coping system to shed water efficiently, the upper surfaces of the blocks 14 slope downwardly in a direction towards the blocks 15 and the upper surfaces of the blocks 15 similarly slope downwardly in a direction away from the blocks 14. In addition, drip grooves 24 are provided in the undersides of the depending ribs 17,19,21 and 22.

In the case where the wall 10 forms a parapet on a building, the coping system described above obviates the need for a conventional roof level shelf angle and a soft joint around the building, thereby enabling a significant saving in costs to be made. Although the coping system does have an unconventional stepped appearance, the step can be arranged to face inwardly of the parapet so that it is not visible from the building exterior.

The coping system also avoids the need to position a.

damp-proof course in the bed joints directly below the blocks 14 and 15, so that the actual location of the damp-proof course can suit particular constructional requirements. This also leaves the region immediately below the coping free for the provision of a tie between the top courses of the two leaves 11 and 12, if desired.

Claims

Claims:

1. A coping or capping system for a cavity wall, comprising a series of first block members mounted on a first leaf of the wall and extending in a row longitudinally of the wall, a series of second block members mounted on a second leaf of the wall and extending in a row longitudinally of the wall, the first members having first surfaces which confront adjacent second surfaces on the second block members, there being no rigid connection between the first and second surfaces.

2. A system as claimed in claim 1, wherein the first block members partially overlap the second block members, and the first and second surfaces are disposed in the area of the overlap.

3. A system as claimed in 2, wherein the first and second surfaces are horizontal or substantially so.

4. A system as claimed in claim 1, 2 or 3, wherein each second block member has an upstanding ridge on its upper surface, and the respective second surface is formed by a surface of the ridge.

5. A system as claimed in claim 4, wherein each first block member has a depending rib on its lower surface, the ribs on the first block members are disposed on a side of the ridges on the second block members opposite to the first leaf, and the ribs vertically overlap the ridges.

6. A system as claimed in any preceding claim, wherein each second block member has depending ribs on its lower surface which locate on either side of the second leaf.

7. A system as claimed in any preceding claim, wherein each of the first and second block members has an upwardly-facing water displacement surface.

8. A system as claimed in any preceding claim, wherein the first block members are staggered relative to the second block members along the length of the wall.

9. A system as claimed in any preceding claim, wherein an air gap is provided between the first and second surfaces.

10. A system as claimed in any one of claims 1 to 8, wherein a compressible member is provided between and is engaged by the first and second surfaces.

11. A system as claimed in claim 10, wherein the compressible member is in the form of a strip.

12. A system as claimed in claim 10 or 11, wherein the compressible member is made of resiliant material.

13. A system as claimed in claim 10, 11 or 12, wherein the compressible member is made of plastics material.

14. A system as claimed in claim 13, wherein the compressible member is made of polyethylene.

15. A coping or capping system for a cavity wall, comprising a series of first block members mounted on a first leaf of the wall and extending in a row longitudinally of the wall, a series of second block members mounted on a second leaf of the wall and extending in a row longitudinally of the wall, the first block members contacting the second block members through the intermediary of a compressible material which is disposed between mutually confronting surfaces on the block members.

16. A copying or capping system for a cavity wall, substantially as hereinbefore described with reference to the accompanying drawing.