GB2155076A

GB2155076A - Damp proof courses for timber framed buildings

Info

Publication number: GB2155076A
Application number: GB08505344A
Authority: GB
Inventors: Peter Robin Cooper; George Carruthers
Original assignee: Reed International Ltd
Current assignee: Reed International Ltd
Priority date: 1984-03-02
Filing date: 1985-03-01
Publication date: 1985-09-18
Also published as: GB8505344D0; GB8405560D0; GB2155076B

Abstract

A damp proof course between a timber wall frame and an underlying structure uses a pre-formed member (7) basically of 'Z' section, the two outer limbs (14, 12) of the 'Z' extending downwardly and upwardly and lying respectively against a surface of the underlying structure (15) on the outer side of the wall and against the lowest timber member (8) on the inner side of the wall and the interconnecting limb (13) of the 'Z' lying on top of the underlying structure (15) between the latter and the lowest timber member (8). <IMAGE>

Description

SPECIFICATION Improvements relating to damp proof courses for timber framed buildings This invention relates to damp proof courses for timber framed buildings to protect the timber wall frames during erection and afterwards against rising damp and casual water.

Theoretically any water that gets into timber frames should dry out through the exterior breathing waterproof membrane. In association with other faults, e.g. a damaged vapour barrier andlorfaulty weathering, the frames may only dry out in an exceptionally hot summer. The intervening period of time could be sufficient to set off a rot pattern.

The object of the invention is to provide a damp proof course which can be fitted correctly requiring minimum skill and which operates efficiently to protect against rising damp and casual water.

According to the present invention a damp proof course between a timber wall frame and an underlying structure such as a brick course or blockwork or a concrete raft, uses a preformed member having basically a 'Z' section, the two outer limbs of the 'Z' extending downwardly and upwardly and lying respectively against a surface of the underlying structure on the outer side of the wall and against the lowest timber member on the inner side of the wall and the interconnecting limb of the 'Z' lying on top of the underlying structure between the latter and the lowest timber member.

Thus the preformed damp course member is self locating and the upwardly extending limb protects the timber from water which may be lying on the floor of the building during erection or may be brought into the building by "wet" trades.

The lowest edge of the downwardly extending limb may be formed as a drip lip which will cause water dripping off this limb to be directed away from the inner wall, and towards an outer wall in the case of cavity wall structure.

The preferred damp course member may have an additional limb which extends down the underlying structure on the inner side of the wall, and so modify the basic 'Z' shape of the member to an 'h' shape.

The additional limb provides a vertical damp proof course connecting with a waterproof member beneath a soiid concrete floor or an underfloor void in the case of a suspended concrete beam floor.

The invention will now be further described by way of example with reference to the accompanying drawings in which: Figure 1 shows a damp proof course according to the invention applied to a cavity wall, and Figure 2 shows a perspective view of the preformed damp proofing member.

The cavity wall has an inner wall 1 and outer wall 2. A concrete floor screed is shown at 3 with a waterproof membrane 4 separating it from the underlying floor structure 5. The membrane 4 extends between the floor screed 3 and the wall 1 and over the course of bricks 15 immediately below the damp proof course 7.

The inner wall 9 is a timber frame wall and in con ventional manner the lowermost timber member is a timber sole plate 8 upon which the rest of the timber framing 9 is supported. The outer wall 2 is a conventional brick wall separated from the wall 1 by cavity 10.

The damp proof course 7 comprises a preformed member, for example, of impact modified PVC or polyethylene so that it will self-seal around the fixing nails 11 to the sole plate 8. Alternatively, the sole plate 8 could be attached to the underlying structure by a bracket, thus obviating the need for the use of a self sealing material. The preformed member has a 'Z' shape with the limbs 12, 13 and 14 of the 'Z' locating as shown in Figure 1 against the inner face of the sole plate 8 on the inner side of the wall 1, between the sole plate 8 and the underlying course of bricks 15 and down the outside face of the course of bricks 15. The lower edge of the limb 14 is bent outwardly to form a drip bead 16 which will deflect water dripping off the limb 14 away from the inner wall 1.

The preformed damp proofing member may have an additional downwardly extending limb 18 as shown in chain-dotted line in Figure 2, to provide a vertical damp proof course between the floor 3 and the wall 1 and so eliminate the need for the waterproof member to extend upwardly from the underside of the screed 3 between the screed 3 and the wall 1. The preformed member is thus modified to an 'h' shape.

Although the damp proof course has been described as applied to a cavity wall it could also be applied to a wall of single skin construction protected by, say, external render or a cladding.

1. A damp proof course between a timber wall frame and an underlying structure using a preformed member basically of 'Z' section, the two outer limbs of the 'Z' extending downwardly and upwardly and lying respectively against a surface of the underlying structure on the outer side of the wall and against the lowest timber member on the inner side of the wall and the interconnecting limb of the 'Z' lying on top of the underlying structure between the latter and the lowest timber member.

2. A damp proof course according to claim 1, wherein the lower edge of the downwardly extending limb of the preformed member is formed as a drip lip which causes water dripping off this limb to be directed away from the inner wall.

3. A damp proof course according to claim 1 or claim 2, wherein the pre-formed member has an additional limb which extends down the underlying

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements relating to damp proof courses for timber framed buildings This invention relates to damp proof courses for timber framed buildings to protect the timber wall frames during erection and afterwards against rising damp and casual water. Theoretically any water that gets into timber frames should dry out through the exterior breathing waterproof membrane. In association with other faults, e.g. a damaged vapour barrier andlorfaulty weathering, the frames may only dry out in an exceptionally hot summer. The intervening period of time could be sufficient to set off a rot pattern. The object of the invention is to provide a damp proof course which can be fitted correctly requiring minimum skill and which operates efficiently to protect against rising damp and casual water. According to the present invention a damp proof course between a timber wall frame and an underlying structure such as a brick course or blockwork or a concrete raft, uses a preformed member having basically a 'Z' section, the two outer limbs of the 'Z' extending downwardly and upwardly and lying respectively against a surface of the underlying structure on the outer side of the wall and against the lowest timber member on the inner side of the wall and the interconnecting limb of the 'Z' lying on top of the underlying structure between the latter and the lowest timber member. Thus the preformed damp course member is self locating and the upwardly extending limb protects the timber from water which may be lying on the floor of the building during erection or may be brought into the building by "wet" trades. The lowest edge of the downwardly extending limb may be formed as a drip lip which will cause water dripping off this limb to be directed away from the inner wall, and towards an outer wall in the case of cavity wall structure. The preferred damp course member may have an additional limb which extends down the underlying structure on the inner side of the wall, and so modify the basic 'Z' shape of the member to an 'h' shape. The additional limb provides a vertical damp proof course connecting with a waterproof member beneath a soiid concrete floor or an underfloor void in the case of a suspended concrete beam floor. The invention will now be further described by way of example with reference to the accompanying drawings in which: Figure 1 shows a damp proof course according to the invention applied to a cavity wall, and Figure 2 shows a perspective view of the preformed damp proofing member. The cavity wall has an inner wall 1 and outer wall 2. A concrete floor screed is shown at 3 with a waterproof membrane 4 separating it from the underlying floor structure 5. The membrane 4 extends between the floor screed 3 and the wall 1 and over the course of bricks 15 immediately below the damp proof course 7. The inner wall 9 is a timber frame wall and in con ventional manner the lowermost timber member is a timber sole plate 8 upon which the rest of the timber framing 9 is supported. The outer wall 2 is a conventional brick wall separated from the wall 1 by cavity 10. The damp proof course 7 comprises a preformed member, for example, of impact modified PVC or polyethylene so that it will self-seal around the fixing nails 11 to the sole plate 8. Alternatively, the sole plate 8 could be attached to the underlying structure by a bracket, thus obviating the need for the use of a self sealing material. The preformed member has a 'Z' shape with the limbs 12, 13 and 14 of the 'Z' locating as shown in Figure 1 against the inner face of the sole plate 8 on the inner side of the wall 1, between the sole plate 8 and the underlying course of bricks 15 and down the outside face of the course of bricks 15. The lower edge of the limb 14 is bent outwardly to form a drip bead 16 which will deflect water dripping off the limb 14 away from the inner wall 1. The preformed damp proofing member may have an additional downwardly extending limb 18 as shown in chain-dotted line in Figure 2, to provide a vertical damp proof course between the floor 3 and the wall 1 and so eliminate the need for the waterproof member to extend upwardly from the underside of the screed 3 between the screed 3 and the wall 1. The preformed member is thus modified to an 'h' shape. Although the damp proof course has been described as applied to a cavity wall it could also be applied to a wall of single skin construction protected by, say, external render or a cladding. CLAIMS

3. A damp proof course according to claim 1 or claim 2, wherein the pre-formed member has an additional limb which extends down the underlying structure on the inner side of the wall.

4. A damp proof course according to claim 3, wherein said additional limb connects at its lower edge with a waterproof membrane.

5. A damp proof course according to any preceding claim, wherein the preformed member is of impact moulded PVC or polyethylene.

6. A damp proof course substantially as hereinbefore described with reference to the accompanying drawings.