GB2178770A - Wall cavity closure - Google Patents

Abstract

A wall cavity closure formed from an extruded plastics or formed metal strip, comprising front and rear surfaces 32, 34 to engage the edges of the outer (12 Figure 1) and inner (14 Figure 1) leaves of a cavity wall at an aperture therethrough, inner front and inner rear surfaces 36, 38 joined to the front and rear surfaces respectively, and extending into the cavity adjacent the leaves of the wall, and a joint surface 40, 42 connecting the inner front and inner rear surfaces by spanning the cavity at a point spaced from the aperture. Between the inner front and inner rear surfaces may be positioned timber blocks (45 Figure 3) and insulating material (48 Figure 3). Wall tie attachment means 50 may be provided on the inner front and rear surfaces, and openings 61 for timber fixings may be formed in the inner and outer surfaces 32, 34. <IMAGE>

Description

SPECIFICATION Wall cavity closure The present invention relates to wall cavity closures in buildings and other structures.

In such buildings having cavity walls, where a win- dow or door aperture occurs it is necessary to span the gap between the two skins of the cavity wall to prevent draug hts and of cou rse to give the appear- anceofasolidwall. In windows, for instance, it is usual to have the window frame situated in the outer skin of the cavity wall, which skin is often a brick layer.

Thus the gap between thetwo layers opens to the inside ofthe structure. ltisverydesirablethereforeto close this gap. In some situationsthewindowframe may itself, at least partially, close the gap, but in any event, it is desirable to provide a special cavity clo sure. A requirement of cavity closures is thatthey should not form a cold bridge between the outside and inside leading to condensation on the closure and masonry. They should also provide a key for plasterwork on the inside ofthe building. They should also form a seal between the window frame and the outer brick layer, preventing the intrusion of moisture therebetween.

Hitherto, such cavity closures have been con structed from pvc extrusions and as such, their per formance is generally satisfactory. One drawback they do have, however, isthattheytendtodegener- ate after some time in use and provide an ineffective plaster key. Moreover, it is always the aim in the building industry to standardise as much as possible on materials so as to achieve cost savings.

It is an object ofthe present invention therefore to provide a wall cavity closure of simple design and construction.

In accordance with this invention there is provided a wall cavity closure to close the sides of an aperture in a cavity wall, said closure comprising a frontsurface and a rear surface adapted to lie adjacent to the sides of the aperture abutting the edges of an outside skin and an inside skin respectively of the cavity wall, an innerfrontsurface disposed perpendicularly and joined to said front surface and an inner rear surface disposed perpendicularly andjoinedto said rearsur- face, said innerfront and inner rear surfaces being adapted to lie adjacent to the inner cavity surfaces of said outside and inside skins respectively of a cavity wall adjacent to the aperture therein, and ajointsur- face joining said inner surfaces together at a distance from their respective connections to the front and rear surfaces and spanning the cavity, said surfaces being formed from a single metal or plastics sheet.

Where the sheet is metal it is preferably galvanised or is stainless steel, either being formed by bending or rolling a sheet along lines lying parallel to its length.

Preferably said jointsurface comprisestwo surfaces, a frontjoint surface joined at an obtuse angleto said innerfrontsurface and a rear joint surface joined at an obtuse angle to said inner rear surface, said front and rear joint surfaces being joined at an angle to one anotherorforming a rounded joint surface.

Preferably said rear surface has a galvanised metal or stainless steel lathing which extends towards but does not connect with said front surface, which lathing is useful as a key for subsequent plasterworkto be applied to the inside skin of the cavity wall.

The space defined by said inner front, inner rear and joint surfaces may be bridged by timber inserts so asto maintain a constantwidth betweentheinner front and inner rear surfaces. These may be held in place as described in UK Patent no. 1,566,160.

It is desirable if, between the timber inserts, polystyrene blocks are disposed to increase the insulation between said innerfrontand rearsurfaces.

A sheet of plastics may be inserted between said front and said innerfront surfaces and the outisde skin of the cavity wall to provide a damp proof course therebetween.

Preferably the inner front and inner rear surfaces are provided with means forth attachment of wal I ties thereto. Said means may comprise a plurality of punched slots through which wall ties having notches formed adjacent one end may be inserted and twisted to lockthem in position. Preferablysaid slots are bridged by the material ofthe closure being still connected to the slot at its two opposite ends. The slot so formed is therefore rectangular, being open only at its sides through segmental apertures.

The invention is further described hereinafter with reference to the accompanying drawings in which: Figure 1 is a cutaway perspective view of a cavity wall window aperture including a cavity closure in accordance with the invention; Figure 2 is a perspective view of a cavity closure in accordance with the invention; Figure 3 is a perspective view of a cavity closure in accordance with the invention disposed between two skins of a cavity wall; and Figure 4is a section through a cavity wall, window frame and cavity closure in accordance with the invention.

In Figure 1 a cavity wall 10 comprises an outside masonry block or brick layer 12 and an inside concrete block layer 14 separated by a gap 16. Awindow aperture 20 is filled by a window frame 22 including a pane of glass 24. Although only a single pane is illustrated in the drawings, it is frequently the case that such a window aperture 20 will be filled with double ortriple glazing. The nature of the glazing forms no partofthe present invention.

The base of the frame 22 is supported on a sill 26 and the top oftheframewill be disposed under a lintel supportingthebrickworkabovethewindowaperture 20.

The wall cavity 16 is bridged by a cavity closure 30 shown in greater detail in Figures 2 to 4.

The cavity closure 30 is constructed from a single sheet of galvanised metal, stainless steel or plastics, fabricated as such or by bending and/or rolling to form front and rear surfaces 32,34, front inner surface 36 and rear inner surface 38 and front joint surface 40 and rearjoint surface 42. Attached to the rear surface 34 is a galvanised metal or stainless steel lathing 44 which partially extends towards front surface 32. So asto prevent the metal lathing forming a cold bridge between the front and rear surfaces, the lathing 44 does not contact the front surface 32.Thus it can be seen thatthe heat path from the inside to the outside which is entirely metal is in fact around all ofthe surfaces 32,36,40,42,38,34 ofthe cavity closure 30.

This is of course very long and therefore provides an effective barrierto heat loss.

The metal lathing 44 is provided as a keyforsubsequent plaster or lining 45to be applied to the inner wall l4uptothewindowframe22.

A gap 47 exists between surfaces 36 and 38 ofthe cavity closure 30 and this is maintained at a specific width by timber blocks 46 disposed therein. Preferably between the timber blocks 46 are disposed polystyrene or insulating blocks 48 which serveto further improve the insulation between the surfaces 36and38.

The cavity closure is sealed with respect to the outer skin 12 by a sheet 49 of plastics forming a vertical damp proofcourse.

With reference to Figures 1 and 2, the innerfront and rearsurfaces36,38andjointsurfaces40,42of the closure 30 are provided with slots 50 disposed along their length. The slots 50 are formed by punching but leaving material of the closure 30 attached thereto at the ends 52 ofthe slots 50. Thus the only opening to the gap 47 ofthe closure is via a pairof segmental apertures 54. Awall tie 56 is punched from sheet metal (galvanised or stainless steel) or plastics and has two arms 58 forming a key in the mortar between the outerskin brickwork or masonry 12 or blockwork 14. The tie 56 has a head 60 which can be inserted into an appropriate slot 50. On rotation of the tie 56the head 60entersthesegmental apertures 54 and locks the tie to the closure 30.In this way, the closure can be rigidly connected to both skins of the cavity wall.

Apertures in the form ofdrillings 61 are formed in the front and rearsurfaces 32, to receive nails or other fixings 62 forthe windowframe 22.

The great advantage with the present invention is that it does away with the necessity of a special cavity closure, and instead uses a design commonly employed as a lintelforsuch a wall. Although it may be made from thinner gauge material, have narrower leaves, have a shorter constant upstand and have no load-bearing capability, nevertheless the design, and hence method of manufacture, of a closure in accordancewith the invention and a lintel in accordance with British Patent no. 1,388,391 is identical. Acavity closure in accordance with the invention can thus very cost-effectively he constructed. In any event, the design of such a cavity closure is very simple, it not requiring any special manufacturing equipment other than standard fabricating, bending, rolling and punching machines.

Claims (11)

1. A wall cavity closure to close the sides of an aperture in a cavity wall, said closure comprising a front surface and a rearsurface adapted to lie adja cent to the sides ofthe aperture, abutting the edges of an outside skin and an inside skin respectively ofthe cavity wall, an inner front surface disposed perpendi cularlyandjoinedto said front surface and an inner rear surface disposed perpendicularly and joined to said rear surface, said innerfront and inner rearsur- faces being adapted to lie adjacentto the innercavity surfaces of said outside and inside skins respectively of a cavity wall adjacent to the aperture therein, and a jointsurfacejoining said innersurfacestogetherata distance from their respective connections to the front and rear surfaces and spanning the cavity, said surfaces being formed from a single metal or plastics sheet.

2. Awall cavity closure according to Claim 1, whereinthejointsurfacecomprisesafrontjointsur- face and a rear joint surface arranged in inclined planes.

3. A wall cavity closure according to Claim 1, wherein the joint surface is rounded.

4. A wall cavity closure according to Claim 1, wherein timber inserts are positioned at intervals between the innerfrontand rearsurfaces.

5. Awall cavity closure according to Claim 4, wherein insulating material is positioned between the timber inserts.

6. Awall cavity closure according to any of the preceding Claims, wherein the joint surface, the inner front surface, or inner rear surface has means forthe attachment of wall ties thereto.

7. Awall cavity closure according to Claim 6, wherein the meansforattachmentofwalltiescom- prises elongate openings or slots.

8. Awall cavityclosure according to Claim 7, wherein the slots are punched from the closure material,theslots being bridged bythe material of the closure in the longitudinal directions ofthe slots.

9. Awall cavity closure according to any of the preceding Claims, wherein the rear surface has fixed thereto a mesh extending towards, but not as far as, the front surface to form a plaster key.

10. Awall cavity closure according to anyofthe preceding Claims, wherein openings are formed at intervals inthefrontand rea r surfaces.

11. Awall cavity closure substantially as herein described and illustrated in Figures 1,2,3 or 4 ofthe Drawings.