GB2119918A - Roof space ventilator - Google Patents

Abstract

A roof space ventilation system comprises: a roof space defined by a floor and a roof ceiling; an insulating material which lines the floor; eaves located at opposite sides of the roof to permit atmospheric air to enter and leave the roof space; a ventilator 1 located adjacent to the eaves between the insulation material and the roof ceiling which provides at least one air channel to facilitate an unimpeded flow of air into and out of the roof space; and a mesh 1a fixed across the or each air channel of the ventilator so that air entering the roof space through the eaves must first pass through the mesh, hence preventing insects gaining access to the roof space through the ventilator. <IMAGE>

Description

SPECIFICATION Roof space ventilator This invention relates to ventilators for use in roof space ventilation systems.

With the increasing use of high levels of insulation in roof spaces it has become increasingly common to use ventilation devices to ensure adequate ventilation to the roof spaces. One of the main purposes of such ventilation is to inhibit the condensation which occurs when moisture laden air finds its way into the roof space through the building fabric.

An example of such a ventilator is described in our copending application No. 8138083.

One problem associated with the use of these ventilators is that they provide easy access for insects and vermin from the outside to the roof space.

It is an object of the present invention to provide a ventilator for use in a roof space ventilation system which prevents insects or vermin from entering the roof space.

According to one aspect of the invention there is provided a roof space ventilator having at least one air channel, and a mesh fixed across the or each air channel so that air may not pass through each air channel without passing through the mesh.

According to another aspect of the invention there is provided a roof space ventilation system comprising: a roof space defined by a floor and a roof ceiling; an insulating material which lines the floor; eaves located at opposite sides of the roof to permit atmospheric air to enter and leave the roof space; a ventilator located adjacent to the eaves between the insulation material and the roof ceiling which provides at least one air channel to facilitate an unimpeded flow of air into and out of the roof space; and a mesh fixed across the or each air channel of the ventilator so that air entering the roof space through the eaves must first pass through the mesh, hence preventing insects gaining access to the roof space through the ventilator.

In a preferred embodiment the ventilator comprises a base having ribs which define a plurality of channels through which air can flow, and at least one cross-member which bridges the ribs to form a rigid structure.

Preferably the ventilator is made from materials which are sufficiently rigid to withstand applied loadings from the insulating material and/or the sarking felt, or the inside of the roof structure in a Dormer construction roof. Most desirably the ventilator is made from plastics such as PVC and in that connection are advantageously vacuum formed.

Optionally the ventilator may be provided with building paper or a similar lining on its lower surface. It is also preferable that the mesh is made from a plastics material.

Reference is now made to the accompanying drawings in which: Figure 1 is a cross-sectional view of a roof space in a building in the region of one of the eaves, showing the main components of a roof space ventilation system; Figure 2 is a perspective partially broken away view of one corner of an embodimentofthe ventilator; Figure 3 is a schematic plan view on a reduced scale of an embodiment of the ventilator for installation into a dwelling during the construction thereof; and Figure 4 is a schematic plan view on the same scale as Figure 3 of the ventilator for installation into an existing dwelling.

Referring to Figure 1, the ventilator 1 is shown in chain lines and positioned in a roof space ventilation system. A mesh 1a is shown connected to that end of the ventilator which is nearest to the eaves. The floor 2 is shown lined with an insulating material 3 which extends over a wall plate 4 which is affixed on top of a traditional wall structure 5. The insulating material is shown extending into a wall cavity, which is filled with a cavity insulation material, 6.

The ventilator is located above the wall plate under the roof tiling 7. This roof tiling is usually on battens on sarking felt. A soffite board 8 restricts the cross-sectional area for airflow through the eaves, ieaving an air gap 9.

The air flow path is shown by the arrows. Air flows through air gap 9 and into the eaves. The interposition of the ventilator between the roof and the insulating material allows a free passage of air, through the ventilator into the roof space. The air may not enter the roof space without first passing through the mesh la. The air circulates through the roof space then leaves through a ventilator at the oppiste side of the house.

Referring now to Figure 2 the ventilator generally designated 1 has a base 10 of which the upper surface is shown here, from which project integral ribs 11. At substantially 90 to these ribs are smaller proportions 12, which increase the rigidity of the ventilator. A mesh la is fitted at one end of the ventilator, over the ribs. The mesh la may be glued or taped to the ribs, preferably where the ribs intersect the cross-members. The mesh is also glued or taped to the underneath of the base of the ventilator.

Each rib has depressions 13 along its length.

Bridging these depressions is a cross-member 14 which is solvent bonded into the depressions. The longitudinal axis of the cross-member is substantially at right angles to the longitudinal axes of the ribs.

The cross-member has a strengthening rib 15 running along its length. In the arrangement shown in Figure 2 the cross-member is integrally formed with a flange 16 which projects over the edge of the and which includes two strengthening ribs 17 and 18.

The slot 19 in the flange is used to fasten the ventilator to joists by passing nails through the slot and into the joists. This flange is employed in embodiments of the invention where the ventilating means is installed during construction of the dwelling. In embodiments of the invention where the ventilating means is installed in an existing dwelling it is convenient for the cross-member to end at the edge of the plate-like member as indicated by the chain lines. In use the underside of the base 10 abuts the insulating material.

Referring now to Figure 3 the arrangement of ribs and cross-members for an embodiment of the invention for installation in a dwelling while under construction is shown. In this arrangement the rectangular ventilator generally designated 1 has a series of transversely oriented ribs 11. Seated upon these ribs are cross-members 14. A mesh la is fixed to one end of the ventilator. Flanges 16 are provided with slots 19 for fixing the ventilator to the roof joists. The air flows through the spaces between the ribs. Typically the ventilator will have an unobstructed air passageway of 0.01 m2 per meter run of eaves.

Referring now to Figure 4, the arrangement of ribs and cross-members for an embodiment of the invention for installation in an existing dwelling is shown. The rectangular ventilator generally designated 1 has a series of transversely extending ribs 11 with longitudinal cross-members 14 seated upon these ribs. A mesh la is fixed to one end of the ventilator. In this embodiment there are no flanges present. The air flows through the spaces between the ribs. The ventilator may be attached to the roof joists using preformed brackets.

Clearly the roof space ventilator of the present invention is advantageous over the prior art. Prior roof space ventilators increase both the air circulation through the roof space and the quantity of insects and vermin entering the roof space, whereas the present roof space ventilator increases the air circulation through the roof space but makes no substantial increase to the quantity of insects entering.

Claims (18)

1. A roof space ventilator having at least one air channel, and a mesh fixed across the or each air channel so that air may not pass through the or each air channel without passing through the mesh.

2. A ventilator according to Claim 1 comprising a base having ribs which define the or each air channel.

3. A ventilator according to Claim 2 in which at least one cross-member bridges the ribs.

4. A ventilator according to Claim 3 in which there are strengthening ribs integrally formed with the or each cross-member.

5. A ventilator according to Claims 3 or 4 in which each cross-member projects beyond the edges of the ventilator.

6. A ventilator according to Claim 5 in which slots are provided in those parts of the or each cross-member which project over the edge of the ventilator to facilitate attachment to supporting elements, such as joists in a roof.

7. A ventilator according to any of Claims 2 to 6 which comprises a plastics material.

8. A ventilator according to Claim 7 which is vacuum formed.

9. A roof space ventilation system comprising: a roof space defined by a floor and a roof ceiling; an insulating material which lines the floor; eaves located at opposite sides of the roof to permit atmospheric air to enter and leave the roof space; a ventilator located adjacent to the eaves between the insulation material and the roof ceiling which provides at least one air channel to facilitate an unimpeded flow of air into and out of the roof space; and a mesh fixed across the or each air channel of the ventilator so that air entering the roof space through the eaves must first pass through the mesh, hence preventing insects gaining access to the roof space through the ventilator.

10. A roof space ventilation system according to Claim 9 comprising a base having ribs which define the or each air channel.

11. A roof space ventilation system according to Claim 10 in which at least one cross-member bridges the ribs.

12. A roof space ventilation system according to Claim 10 in which there are strengthening ribs integrally formed with the or each cross-member.

13. A roof space ventilation system according to Claims 11 or 12 in which each cross-member projects beyond the edges of the ventilator.

14. A roof space ventilation system according to Claim 13 in which slots are provided in those parts of the or each cross-member which project over the edge of the ventilator to facilitate attachment to supporting elements, such as joists in a roof.

15. A roof space ventilation system according to any of Claims 10 to 14 which comprises a plastics material.

16. A roof space ventilation system according to Claim 15 which is vacuum formed.

17. A ventilator substantially as herein described with reference to and as shown in the accompanying drawings.

18. A roof space ventilation system substantially as herein described with reference to and as shown in the accompanying drawings.