GB2376039A - Cavity closure - Google Patents

Abstract

A cavity closure for use with a cavity wall comprises a cavity closure region <B>20</B> arranged to be received within part of a cavity of the wall adjacent a door or window opening and a flange region <B>18</B> arranged to overlie a part of one of the leaves of the wall. Part of the cavity closure region <B>20</B> is composed of a material comprising a mixture of a plastics material and a cellulose material. Other parts of the cavity closure may be composed of the material. The cellulose material may comprise crushed leaves, wood chips or sawdust and may make up between 30% and 80% by weight of the material. The material may include additives which may enhance the fire retarding capability of the cavity closure.

Description

<Desc/Clms Page number 1>

"Cavity Closure" This invention relates to a cavity closure, and in particular to a cavity closure having improved thermal properties.

Cavity closures are well known for use in closing the cavity of a cavity wall around an opening into which a window or door frame is to be fitted, the cavity closure further serving to anchor the window or door frame in position, when fitted. The cavity closure typically comprises lengths of extruded plastics material of an appropriate section and of appropriate dimensions to permit the cavity closure to be received, at least in part, within the cavity of the wall with which the cavity closure is to be used. The cavity closure further typically includes at least one flanged region arranged to overlie a part of the wall at the opening to provide a surface to which the window or door frame can be secured.

There is a requirement to improve the thermal insulating properties of new buildings. Although the provision of cavity walls results in buildings having reasonably good thermal insulating properties, where the cavity is breached, then heat can be conducted between the leaves of the cavity wall, thereby giving rise to unnecessary heat loss from the building.

It is an object of the invention to provide a cavity closure of improved thermal properties.

According to the present invention there is provided a cavity closure for

<Desc/Clms Page number 2>

use with a cavity wall, the cavity closure comprising a cavity closure region arranged to be received, in use, within a part of a cavity of the wall adjacent a door or window opening, and a flange region arranged to overlie a part of at least one of the leaves of the wall, wherein at least part of the cavity closure region is composed of a material comprising a mixture of a plastics material and a cellulose material.

The use of a cellulose material in the material used in the formation of the cavity closure region results in the cavity closure region being of good thermal insulating properties. As a result, there is a reduced risk of heat being conducted at a high rate between the leaves of the cavity wall, thus the thermal insulating properties of a building in which the cavity closure is used are improved.

In addition to improving the thermal properties of the cavity closure, the use of a cellulose material in the material of the cavity closure region further allows a wide range of fixing devices to be used with the cavity closure region, for example nails, screws and adhesives.

The flange region and cavity closure region may be separate components, but in an alternative arrangement, the flange region and the cavity closure region are integral with one another.

If desired, the flange region may also be of a material comprising a mixture of a plastics material and a cellulose material. As mentioned above, the

<Desc/Clms Page number 3>

use of this material has the advantages that the flange region is of good thermal properties, a wide range of fixing techniques can be used with the material, and in addition, a number of finishing techniques can be used on the product, for example the finished product may be painted.

One or more additives may be included in the material, for example to enhance the fire retarding properties of the cavity closure.

In common with a number of existing cavity closures, the cavity closure of the present invention is conveniently of extruded form. In accordance with the invention, prior to extrusion, a cellulose material is mixed with the plastics material. Although the cellulose material could take the form of any natural wood/plant material, for example crushed leaves or wood chips, in a particularly advantageous arrangement, the material used is saw dust.

Rather than taking the form of simple extrusions, if desired, the material of the cavity closure may be of cellular form. Such a material has the advantage that the product can be of low weight whilst remaining sufficiently strong and of sufficient rigidity to meet the structural requirements of a cavity closure.

The invention will further be described by way of example, with reference to the accompanying drawings in which: Figure 1 is a sectional view of a cavity closure in accordance with an embodiment of the invention, in use, supporting the lower part of a window

<Desc/Clms Page number 4>

frame ; Figure 2 is a view of the cavity closure of Figure 1 in use supporting a side part of the window frame ; and Figure 3 is a view of an alternative cavity closure.

The accompanying drawings illustrate part of a cavity wall 10 made up of a pair of leaves 12,14 of brick or block construction. The cavity wall 10 includes an opening, extending through both leaves thereof and within which a window frame 16 is to be installed. A cavity closure 18 is mounted partially within the cavity adjacent the opening.

The cavity closure 18 illustrated in the accompanying drawing comprises a cavity closure region 20 and a flange region 22. Both of these components 20, 22 are of extruded form, the flange region 22 being extruded from a suitable plastics material, and the cavity closure region 20 being extruded from a material comprising a suitable plastics material mixed with a quantity of saw dust.

The cavity closure region 20 is of box-like section, including an upper wall 24, a lower wall 26 and a pair of side walls 28. The side walls 28 are each shaped to define a recess 30 which, if desired (as shown in Figure 2), can receive an end of a tie 32 secured between two adjacent rows of bricks or blocks of one of the leaves 14 of the wall 10 with which the cavity closure is used to secure the cavity closure in position. The upper wall 24 is shaped to define a pair of

<Desc/Clms Page number 5>

recesses 34 arranged to receive, by slide fitting from an end thereof, respective projections 36 forming part of the flange region 22. In addition, the flange region 22 carries projections 42 arranged to locate within an opening 44 provided in the cavity closure region 20 serving to locate the flange region 22. Once the flange region 22 and cavity closure region 20 are correctly positioned relative to one another, an expanding adhesive is used to lock those components to one another.

The flange region 22 is designed to overlie part of the exposed surfaces of the bricks or blocks of the leaves 12,14 at the opening, the flange region 22 including a region 38 provided with saw tooth-like projections 40 which cooperate, in use, with a tongue 46 carried by the window frame to secure the window frame in position.

As mentioned hereinbefore, the cavity closure region 20 is constructed from a material comprising a mixture of a suitable plastics and a wood material in the form of saw dust. As a result, the cavity closure region 20 is of good thermal properties, resulting in the conduction of heat between the leaves 12,14 of the wall 10 being reduced, and hence allowing the thermal properties of a building to be improved. In addition, the material allows nails or screws to be driven securely into the material.

Although in the arrangement described hereinbefore the cavity closure

<Desc/Clms Page number 6>

region 20 is of box-like section, it will be appreciated that this need not be the case and the cavity closure region 20 and flange region 22 may be designed in such a manner that the assembled cavity closure is of, for example, open channel shaped form or shaped to include a central support leg from each side of which extensions project.

In the arrangement described hereinbefore, the cavity closure is of twopart form with one of the components thereof being manufactured from a material including a cellulose material and a plastics material. It will be appreciated, however, that this need not be the case and the invention also relates to cavity closures of one-piece design. Further, although in the arrangement described hereinbefore the components of the cavity closure are simple extrusions, if desired the components could be of cellular form resulting in the weight of the components being reduced whilst maintaining the strength and rigidity thereof The cellulose material used in the cavity closure region is conveniently of saw dust form. It will be appreciated, however, that this need not be the case and that the material could take the form of wood chips, crushed leaves or any other suitable material. The plastics material could, for example, be PVC, polyethylene or polypropylene.

The proportion of the material of the cavity closure region made up of the

<Desc/Clms Page number 7>

cellulose material is conveniently within the range 30% to 80% by weight. A material suitable for use in the invention is sold by Lesco Technology Pte. Ltd in the form ofPVC/wood composite granules. Although this material is suitable for use in the invention, it will be appreciated that other materials could be used in the invention and that the invention is not restricted to the use of this material.

If desired, one or more additives may be included in the material of the cavity closure. By way of example, a suitable additive may be used to enhance the fire retarding capability of the cavity closure. Additives achieving other effects, for example to enhance the visual appearance of the cavity closure could alternatively or additionally be used.

Figure 3 illustrates an alternative use for a cavity closure. In the arrangement of Figure 3, the cavity closure 18 is mounted upon the frame 50 of a timber framed building, and a window frame 16 is secured to the cavity closure. An outer brick work skin 52 can subsequently be constructed around the frame 50. Obviously, the use of a cellulose/polymer blend material, for example a plastics material containing saw dust, in the cavity closure will have the advantages described hereinbefore.

Claims (9)

1. CLAIMS 1. A cavity closure for use with a cavity wall, the cavity closure comprising a cavity closure region arranged to be received, in use, within part of a cavity of the wall adjacent a door or window opening, and a flange region arranged to overlie a part of at least one of the leaves of the wall, wherein at least part of the cavity closure region is composed of a material comprising a mixture of a plastics material and a cellulose material.
2. 2. A cavity closure according to Claim 1, wherein the cavity closure region and the flange region are integral with one another.
3. 3. A cavity closure according to Claim 1, wherein the cavity closure region and the flange region are separate components connectable to one another.
4. 4. A cavity closure according to any one of the preceding claims, wherein at least part of the flange region is composed of a material comprising a mixture of a plastics material and a cellulose material.
5. 5. A cavity closure according to any one of the preceding claims, wherein the material further includes at least one additive.
6. 6. A cavity closure according to Claim 5, wherein the additive or at least one of the additives serve to enhance the fire retarding capability of the cavity closure.
7. 7. A cavity closure according to any one of the preceding claims, wherein

   <Desc/Clms Page number 9>

   the cellulose material comprises at least one of crushed leaves, wood chips and saw dust.
8. 8. A cavity closure according to any one of the preceding claims, wherein the cellulose material makes up 30 to 80% by weight of the material.
9. 9. A cavity closure substantially as hereinbefore described with reference to any of the accompanying drawings.