GB2136473A

GB2136473A - Roofspace ventilation device

Info

Publication number: GB2136473A
Application number: GB08406792A
Authority: GB
Inventors: Clarence A Hawkins
Original assignee: GRA MAR BUILDING PRODUCTS LIMI
Current assignee: GRA MAR BUILDING PRODUCTS LIMI
Priority date: 1983-03-15
Filing date: 1984-03-15
Publication date: 1984-09-19
Also published as: GB2136473B; GB8406792D0

Abstract

The device (10) for mounting in the upper edge of a fascia board or the like beneath the edge portion of a roof has an elongate outer wall (12) and an elongate inner wall (14) both of L-shaped cross-section. The walls (12, 14) are located parallel to each other and joined together by a plurality of spacers (18) defining the width of a ventilation passage (16) extending between the two walls (12, 14) along the length of the device. An insect grille (24) spans the ventilation passage (16). The L-shaped inner wall (14) constitutes a means for locating the device on the top edge of the fascia board, the tiles and lining of the roof edge portion resting on upper surface of the outer wall (12). Rain and other precipitation is prevented from entering the roofspace by the downwardly directed slot opening provided by the L-shaped cross section of the walls. <IMAGE>

Description

SPECIFICATION Roofspace ventilation method and device This invention relates to a roof ventilation method and device for providing an air passage between a roofspace and the atmosphere outside.

It is a requirement in the United Kingdom that the roofspace in new buildings having insulated ceilings be ventilated to reduce the possibility of condensation. Several devices and construction methods have been proposed to meet the requirements of providing adequate ventilation and a barrier to windborne precipitation, but these devices and methods often suffer from the disadvantage of being comparatively expensive to manufacture or to install. Ventilation means are now also being provided in refurbished properties. The construction of the roof edges in such properties often prevents the use of the prior art devices and methods, particularly when the eaves fascia board is attached directly to the face of the wall.

It is an object of this invention to provide means of ventilating a roofspace involving a device which is relatively simple to manufacture and install and which can be used in refurbished buildings or in new works.

According to this invention, a method of ventilating a building roofspace comprises fitting an elongate duct element to the upper edge of a wall, fascia board, or the like located beneath an edge portion of a roof enclosing the roofspace, the duct element defining a ventilation passage having a downwardly directed exterior slot opening and an inwardly directed interior slot opening with both slot openings extending lengthwise of the duct element and generally parallel to the said upper edge. The duct element preferably comprises an outer wall or shield of L-shaped cross section joined by a plurality of spacers to a parallel inner wall for locating the device on a fascia board edge, the spacers defining the width of the ventilation passage.The downwardly directed exterior opening and the resulting L-shaped cross-section of the air passage between the walls largely prevents the ingress of rain to the roofspace, and consequently avoids the need for elaborate ducting behind or between the rafters in many instances.

A wire mesh insect screen is advantage ousiy mounted along the length of the duct element and extends from the inner wall to the outer wall.

The invention will now be described by way of example with reference to the drawings in which: Figure 1 is a perspective view of a duct element portion; Figure 2 is a cross-section of the duct element of Fig. 1; Figure 3 is a cross-section of part of a building in the region of the eaves showing the duct element of Fig. 1 installed on a fascia board fixed directly to the wall of the building; Figure 4 is a cross-section of part of a building in the region of the eaves showing the duct element of Fig. 1 installed on a fascia board spaced away from the wall; Figure 5 is a perspective view of an insulation barrier for use in the installation shown in Fig. 4; Figure 6 is perspective view of a spring clip for clamping a roof lining edge portion to the duct element; and Figure 7 is a sectioned view of the duct element of Fig. 1, showing the spring clip of Fig. 6 in position.

Referring to Figs. 1 and 2, a duct element 10 in accordance with the invention has an outer wall 1 2 and an inner wall 14, both of Lsection, these walls defining an L-shaped lateral air passage 1 6 which extends the length of the duct element 1 0. Fig. 1 shows only a section of the duct element 10. It may be cut to any required length, and can conveniently be supplied in 1 yard lengths. Spacer pillars 18, located at regular intervals along the element 10, support the outer wall 1 2 relative to the inner wall 14, and are each formed with an internal bore 20 so that, if necessary, a fixing nail (not shown) can be driven through holes 22 in the walls 1 2 and 14. The walls are conveniently formed from plastics material and produced by extrusion.

A plastics or wire mesh insect screen 24 is bonded along each of its edge portions in grooves in the inner and outer walls 1 2 and 14.

Referring to Fig. 3, the duct element 10 may be installed with roofing tiles in situ, on the top edge of a fascia plate 26 mounted directly against the wall 28 of a building, as is common in older properties. The edge portion of roofing felt 30 is laid over the duct element 10 so as not to block the air passage between the exterior and the roof space 32, and allowing water to discharge into the gutter 33. The weight of the roofing tiles 34 is supported by the upper surface of the outer wall 1 2 and is generally sufficient to hold the duct element 10 in position on the fascia plate 26.

It will be seen that the element 10 as installed provides a downwardly directed inlet opening which largely prevents ingress of wind-borne precipitation into the roofspace 32, so that additional screening or the like is not required between the rafters 36. A wall plate 38, conventionally placed above the level of the interior ceiling 40, acts as a barrier for preventing insulation material 42 blocking the inner opening of the duct 10.

In buildings having deeper eaves with the fascia board 26 spaced away from the wall 28, it is preferable to include an insulation barrier 44 spanning the rafters 36, as shown in Figs. 4 and 5. Plastics sheeting, preferably corrugated, may be used for the barrier, this being preformed and then folded into a shallow U-shaped section with flanges 46 for fixing the barrier to the top face of the rafters 36 and to the front edge of the wall plate 38 as shown in Fig. 5.

If the edge of the roof lining 30 requires securing, a spring clip 48 may be used, as shown in Figs. 6 and 7. The clip 48 has two upper jaws 50 and 52 with small projections 54 for clamping respectively the lining 30 and, where applicable, an L-shaped tile infill 56 to the upper surface of the outer wall 1 2.

The clamping force is exerted by a lower jaw 58 of the clip 48 which clips around the lower edge of the outer wall.

Claims

1. A method of ventilating a building roofspace in which an elongate duct element is fitted to an upper edge of a wall, fascia board or the like which is located beneath an edge portion of a roof enclosing the roofspace, the duct element defining a ventilation passage having a downwardly directed exterior slot opening and an inwardly directed interior slot opening with both slot openings extending lengthwise of the duct element and generally parallel to the said upper edge.

2. A method according to claim 1, wherein the duct element includes an outer shield which is generally L-shaped in a crosssection of the element and is spaced from the wall or fascia board by a plurality of spacers to define, behind the shield, a ventilation passage having two parts which, in crosssection, are generally at right angles to each other.

3. A method according to claim 1 or claim 2, wherein the duct element is located on an outer upper edge of the wall or fascia board by an inner support member of L-shaped cross-section and forms part of the duct element.

4. A method according to any preceding claim, wherein the duct element is fitted beneath an edge portion of a flexible roof lining.

5. A method according to claim 4, wherein the roof lining is secured to the duct member by a plurality of spring clips.

6. A method according to any preceding claim, wherein the duct element is secured to the wall or fascia board by nails driven through bores extending through the spacers.

7. A method according to any preceding claim, wherein a separate insulation barrier is secured between rafters of the roof to prevent interruption of ventilation between the roofspace and the said interior opening by loose insulation material.

8. A roofspace ventilation device comprising an elongate duct element having an outer wall which is generally L-shaped in a crosssection of the element, and means including a plurality of spacers joined to the outer wall for locating the element on the edge of a fascia board or the like with the outer wall generally parallel to the said edge and thereby defining a ventilation passage in the region between the outer wall and the edge.

9. A ventilation device according to claim 8, wherein the locating means comprises an inner wall of L-shaped cross section extending parallel to the outer wall.

10. A ventilation device according to claim 9, further comprising a grille in the form of a strip of net material extending the length of the device and spanning the ventilation passage between the outer wall and the inner wall.

11. A ventilation device according to any of claims 8 to 10, wherein the spacers comprise pillars having a central bore for fixing the device to the edge of a fascia board.

1 2. A ventilation device according to any of claims 8 to 11, further comprising a plurality of spring clips for clamping a roof lining edge portion to the outer wall.

1 3. A method of ventilating a building roofspace, the method being substantially as herein described with reference to the drawings.

1 4. A ventilating device constructed and arranged substantially as herein described and shown in the drawings.