GB2450798A

GB2450798A - Damp course

Info

Publication number: GB2450798A
Application number: GB0811975A
Authority: GB
Inventors: John Louis Shillabeer
Original assignee: Cavity Trays Ltd
Current assignee: Cavity Trays Ltd
Priority date: 2007-07-05
Filing date: 2008-06-30
Publication date: 2009-01-07
Anticipated expiration: 2028-06-30
Also published as: GB0811975D0; GB0713081D0; GB2450798B

Abstract

The invention relates to a building component e.g. a damp proof course for a cavity wall 10, particularly one whose inner skin 14 is of timber. The building component comprises a first horizontally extending portion 22 through or beneath an outer skin of a wall 12. A second horizontally extending portion 26 extends through or beneath an inner skin 14 of the cavity wall, and an intermediate portion 24 connects the first and second portions. The intermediate portion further comprises an upright portion 28 adjacent to the inner wall 14. A membrane 30 on the cavity face of the inner skin 14 is dressed over the upright portion 28. Preferably the inner portion 26 may project beyond the inner skin 14 and be joined to an oversite membrane 32. Later embodiments relate to a wall construction and a method of construction comprising said building component.

Description

DAMP COURSE

The present invention relates to the provision of damp courses (or damp proof courses, DPCs) in cavity walls, particularly cavity walls involving timber frame construction. In various aspects the invention provides a component for use in providing a damp course, a wall construction incorporating such a damp course, and a method of construction.

For a cavity wall of timber frame construction, where the inner skin of the cavity wall is constructed at least partially of timber, it is generally important to protect the timber frame skin from dampness. Inner skins of other types may also require protection against damp. The British Standards and Codes of Practice stipulate the use of a damp course at the base of both skins.

Where the wall forms part of a building on contaminated land from which a gas such as radon or methane may permeate, the construction desirably resists the entry of the gas into the building, where it might cause a health hazard.

In a first aspect the present invention provides a building component having a horizontally-extending web with a first portion for extending at least partly through or beneath an outer skin of a cavity wall; a second portion for extending through or beneath an inner skin of the cavity wall; and an intermediate portion which is intended to be located within the cavity of the cavity wall and which connects said first and second portions and includes an upstanding portion adjacent to the second portion.

Preferably the intermediate portion includes a portion sloping downwardly from the bottom of the upstanding portion towards the first portion.

The building component is desirably formed of material that is rigid enough for it to be self-supporting. It may be a plastics extrusion.

In a second aspect the present invention provides a wall construction comprising a cavity wall having a outer skin and an inner skin, the inner skin comprising timber and being spaced from the outer skin by a cavity; and the building component according to the first aspect incorporated under or in a lower region of the cavity wall, with the first portion extending at least partly through or beneath the outer skin, the second portion extending through or beneath the inner skin, and the upstanding portion preferably lying against the face of the inner skin within the cavity.

Preferably the second portion extends frilly through the inner skin and projects from it. The projecting portion may be connected to an oversite membrane (typically for providing gas barrier properties).

Preferably the face of the inner skin is at least partly covered by a membrane which is coupled to or dressed over the upstanding portion of the building component.

In a third aspect the invention provides a method of construction including locating a building component according to the first aspect at or adjacent the base of an intended wall, and building up the wall to produce a wall construction according to the second aspect.

Some embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig 1 is a vertical section through a wall construction embodying the second aspect of the invention and incorporating a building component embodying the first aspect; and Fig 2 is a vertical section through a second embodiment.

Fig I shows a cavity wall 10 having an outer skin 12 of masonry, and an inner skin 14 of timber, spaced from the outer skin 12 by a cavity 16. A floor surface 18 extends inwardly from adjacent the base of the inner, timber skin 14.

A building component 20 is built into the wall, adjacent the base. This component is a relatively rigid (self-supporting) element, suitably a plastics extrusion.

An outer horizontal portion 22 extends filly through the outer skin 12, terminating at the outer face thereof. At the inner (cavity) side, the outer portion 22 is integral with a sloping portion 24, which rises upwardly while bridging the cavity, and is integral at its inner end with a second horizontally extending portion 26. This second portion 26 extends through the timber inner skin 14, and projects beyond it. At the junction of the inner portion 26 and the sloping portion 24, there is a vertical wall portion 28 which lies against the face of the inner skin 14 within the cavity 16. Above this upright portion 28, the inner surface of the timber skin 14 is covered by a membrane 30, whose lower portion is dressed over the upright wall portion 28.

The inner horizontal portion 26 is connected to an oversite membrane 32.

Thus by incorporating the building component 20 in the wall construction, protection is provided against water permeating inwardly via the cavity, against rising damp in the inner or in the outer skin, and against gas rising upwardly from the ground. Furthermore, the component 20 provides a link with the oversite membrane 32, and a link with the membrane 30 on the cavity side of the inner skin. All these are achieved by means of the single component, installed in a single operation.

The component 20 shown in Fig I has portions 22,26 which extend through the different skins 12,14 at different levels. There is the difference in level between the portions 22,26 because they are connected to opposite ends of the sloping intermediate portion 24. Fig 2 shows an alternative arrangement in which there is a continuous horizontal web 40, successive parts of which provide the first portion 22' for extending through the outer skin 12; an intermediate portion 24' which bridges the cavity 16, and a second portion 26' which passes through the inner skin and may be connected to an oversite membrane. The intermediate portion also includes a sloping portion 24", rising from the inner edge of the first portion 22', and leading to the upright wall portion 28.

As shown in dotted lines in Figs 1 and 2, a block of insulating foam 44 of triangular section may be provided, filling the space beneath the sloping portion (24 or 24").

Claims

I. A building component having a first horizontally-extending web portion for extending at least partly through or beneath an outer skin of a cavity wall; a second horizontally-extending web portion for extending through or beneath an inner skin of the cavity wall; and an intermediate portion which is intended to be located within the cavity of the cavity wall and which connects said first and second portions and includes an upstanding portion adjacent to the second portion.
2. A building component according to claim 1 in which the intermediate portion includes a portion sloping downwardly from the bottom of the upstanding portion towards the first portion.
3. A building component according to claim 2 in which said second portion extends rearwardly from adjacent the bottom of the upstanding portion.
4. A building component according to claim 2 in which the first and second portions are coplanar and are coupled by a coplanar portion of the intermediate portion; and wherein said sloping portion extends upwardly and rearwardly from said coplanar portion adjacent the first portion.
5. A building component according to claim 2, 3 or 4 including a foam block attached to the underside of said sloping portion.
6. A building component according to any preceding claim which is formed of material that is rigid enough for it to be self-supporting.
7. A building component substantially as herein described with reference to and as illustrated in the accompanying drawings.
8. A wall construction comprising a cavity wall having a outer skin and an inner skin, the inner skin comprising timber and being spaced from the outer skin by a cavity; and a building component according to any preceding claim incorporated under or in a lower region of the cavity wall, with the first portion extending at least partly through or beneath the outer skin, the second portion extending through or beneath the inner skin, and the upstanding portion lying against the face of the inner S skin within the cavity.
9. A wall construction according to claim 8 wherein the second portion extends frilly through the inner skin and projects from it.
10. A wall construction according to claim 9 wherein the projecting second portion is connected to an oversite membrane.
11. A wall construction according to claim 8, 9 or 10 wherein the face of the inner skin in the cavity is at least partly covered by a membrane which is coupled to or dressed over the upstanding portion of the building component.
12. A wall construction substantially as herein described with reference to and as illustrated in the accompanying drawings.
13. A method of construction including locating a building component according to any of claims I to 7 at or adjacent the base of an intended wall, and building up the wall to produce a wall construction according to any of claims 8 to 12.