GB2281389A

GB2281389A - Ventilator

Info

Publication number: GB2281389A
Application number: GB9317417A
Authority: GB
Inventors: Paul Bottomore
Original assignee: THREAPLETON SIMON NICHOLAS
Current assignee: THREAPLETON SIMON NICHOLAS
Priority date: 1993-08-21
Filing date: 1993-08-21
Publication date: 1995-03-01
Also published as: GB9317417D0

Abstract

A rafter ventilator (1) comprises a base member (2) with side walls (3, 4). In use, a ventilation path is defined between the base member (2), the side walls (3, 4) and the underside of a roof structure against which the ventilator (1) is placed. Both ends of the ventilation path are provided with grilles (6, 7) to prevent ingress of insects or other material. The ventilator (1) is vacuum-formed from plastics material, eg PVC. <IMAGE>

Description

Title - Ventilator This invention relates to a ventilator for use in building structures, more particularly to a rafter ventilator for the ventilation of a roof space.

In roof construction, if loft insulation is laid, it is commonly a requirement of building regulations that the roof be ventilated. One form of ventilators which is commonly used for this purpose is a rafter ventilator. Rafter ventilators typically comprise vacuum-formed plastics components which are fitted into the roof at the point where the insulation and roof meet. Such a ventilator typically comprises a base plate with upstanding side walls which space the base plate from the underside of the roof, thereby defining a ventilation path.

Particularly when the ventilator is for use on eaves with open soffits, the external end of the ventilation path may be provided with a flyscreen to prevent ingress of insects into the roof space.

A problem common to all forms of roof ventilator is that, over protracted periods of time, the ventilation path may become partially or totally blocked, reducing the effectiveness of the ventilator and leading to problems of condensation in the roof space.

There has now been devised an improved form of rafter ventilator which overcomes or substantially mitigates the disadvantages associated with known forms of such ventilators.

According to the invention, there is provided a rafter ventilator comprising a base member with side walls upstanding therefrom, such that a ventilation path is defined between the base member, the side walls and the underside of a roof structure against which the ventilator is placed, in use, wherein both ends of the ventilation path are provided with grilles.

The ventilator according to the invention is advantageous primarily in that it has a reduced tendency to block than previously known forms of rafter ventilator, and hence maintains more efficient ventilation of the roof space and reduces the likelihood of problems associated with poor ventilation.

The ventilator of the invention is conveniently formed, eg by vacuum-forming, from plastics material, eg PVC.

The dimensions of the ventilator of the present invention may be generally similar to those of known forms of rafter ventilator.

The width of the base member may be such as to fit within a standard rafter spacing, eg 400mm, 450mm or 600mm. The depth of the side walls may be such as to provide the minimum gap between insulation and roof required by building regulations, eg 25mm.

The grilles at both ends of the ventilation path will have mesh sizes sufficient to provide the ventilation gap required by the relevant building regulations. Typical figures are 1O,000mm2 and 25,000mm2. The mesh size may typically be 4mm.

The base member is preferably provided with one or more ribs arranged parallel to the side walls. These provide added strength to the ventilator and also serve to mainten the spacing between the base member and the underside of the roof.

The invention will now be described in more detail, by way of illustration only, with reference to the accompanying drawings, in which Figure 1 is a perspective view of a section of a rafter ventilator according to the invention; Figure 2 is a sectional side view showing the ventilator of Figure 1 installed in a roof; and Figure 3 is a view similar to Figure 2, showing a slightly modified form of ventilator according to the invention installed in a second roof, of lesser pitch than that of Figure 2.

Referring first to Figure 1, a rafter ventilator (generally designated 1) is vacuum-formed from PVC. The ventilator (1) comprises a base plate (2) with two upstanding side walls (3,4) and five parallel ribs (5) which extend along the base plate (2), parallel to the side walls (3,4).

Inclined mesh panels (6,7) are arranged at each end of the base plate (2). The lower edge of each mesh panel (6,7) is actually lower than the base plate (2), thereby defining a step formation (8), as is more clearly visible in Figure 2.

As shown in Figure 2, the ventilator (1) is positioned between the rafters (21) of a roof structure, at the point where the roof meets a cavity wall (22). The roof includes a layer of underlay (23) laid over the rafters (21), tiles (24) being laid on top of the underlay (23). The roof space is insulated by a layer of insulating material (25).

The ventilator (1) is positioned with its open face against the underside of the underlay (23). The external top corner of the topmost brick in the wall (22) is located against the step formation (8), which is formed at such an angle that the ventilator (1) is inclined at substantially the same angle as the pitch of the roof.

The ventilator (1) maintains an air-gap between the insulating material (25) and the roof, thereby effecting ventilation of the roof space, the air path being shown by the arrows in Figure 2.

The ventilator (30) shown in Figure 3 is identical to that of Figures 1 and 2 in all respects, save that the step formation (31) is inclined at a different angle. This means that when the step formation is pressed into abutment with the topmost brick in the wall, the ventilator (30) is inclined at a shallower angle suitable for use in a roof with a lesser pitch.

Claims

1. A rafter ventilator comprising a base member with side walls upstanding therefrom, such that a ventilation path is defined between the base member, the side walls and the underside of a roof structure against which the ventilator is placed, in use, wherein both ends of the ventilation path are provided with grilles.

2. A ventilator as claimed in Claim 1, which comprises plastics material.

3. A ventilator as claimed in Claim 2, which is formed by vacuum forming.

4. A ventilator as claimed in Claim 2 or Claim 3, formed from polyvinylchloride.

5. A ventilator as claimed in any preceding claim, wherein the base member is provided with one or more ribs arranged parallel to the side walls.

6. A ventilator substantially as hereinbefore described and as illustrated in the accompanying drawings.