GB2185501A

GB2185501A - Channel members which replace roof rafters

Info

Publication number: GB2185501A
Application number: GB08525125A
Authority: GB
Inventors: Frank V Greaves
Original assignee: TAC METAL FORMING Ltd
Current assignee: TAC METAL FORMING Ltd
Priority date: 1985-10-11
Filing date: 1985-10-11
Publication date: 1987-07-22
Also published as: GB2185501B; GB8525125D0

Abstract

At least some of the rafters in a roof construction are replaced by channel members 1 attached together in side-by-side relation, with the major axis of each channel extending down the slope of the roof and with the outer part of the roof 4, 5, 6, 7, attached to the upstanding edge portions of the channels. <IMAGE>

Description

SPECIFICATION Improvements in and relating to roofing systems This invention relates primarily to roofing systems wherein the final, outer surface of the roof is to be tiled or slated, although a final surface based on cladding sheets or panels is also possible.

Normal practice for roofs which are tiled or slated is for a supporting timber structure to be erected, comprising at least one main roofing purlin carrying a number of rafters which extend down the slope of the roof.

Roofing felt is applied over the whole assembly, followed by battens to which the final surface layer of tiles, slates or sheet is then affixed, by nailing. Such roof constructions are very well-known; they need not be further described in detail. However, they have certain disadvantages, particularly where it is desired to enhance the thermal insulation properties by adding a layer of fibrous insulation material.

This can be done by using an inner cladding of plasterboard, or a fire protection board, to support a fibrous mat in the spaces between the rafters and purlins. Unfortunately, any subsequent water penetration of the structure may be difficult to detect and/or locate, at least until signs of damp or even rot appear on the inner surface of the cladding. Also air circulation/natural ventilation) at the underside of the roof is very drastically reduced, which is in itself likely to promote fungal growth.

Accordingly, it is more usual to provide a so-called false ceiling to carry the insulation layer, leaving a completely clear air space immediately adjacent the inside of the roof structure itself. This often results in at least some wasted space inside the building.

According to the present invention,at least some of the rafters of a roof of the kind above described are replaced by channel members attached together in side-by-side relation with the major axis of each channel extending down the slope of the roof and with the outer part of the roof attached to the upstanding edge portions of said channels.

Preferably, the spaces thus defined between the channel members and the outer part of the roof are filled with an insulation material such as glass fibre mat or rigid foam insulation slabs.

Preferably all the conventional rafters are replaced by a series of channel members, the latter being supported entirely by the purlins, or by such purlins and additional purlins as may be needed to confer adequate resistance to bending of the channels. The channels are preferably of metal, for example, of cold formed galvanised steel. It is particularly advantages to use plastics coated metal in order to maximise resistance to corrosion. Where metal channels are used, these may be bolted or rivetted together through their upwardly-di rected edges. The latter may be profiled to overlap with adjacent edges so as to present an outwardly-facing (referring to the outer sur face of the roof) flat portion to which roofing felt and/or roofing battens can be attached by bolts, rivets and/or self-tapping screws.

This arrangement is especially convenient because it results in a series of parallel, nar row flat strips extending down the roof slope and spaced apart by the width of a channel.

These strips are of course each analogous to a conventional rafter.

Because the sloping channel members are inherently adapted to be self-draining, even if water penetration occurs through the outer surface of the roof, it should not cause a sig nificant problem, in that adventitious water will not be able to soak into any timber, or plaster board inner lining.

It will be appreciated that the invention just described has significant advantageous over the traditional timber roof construction.How ever, it is not limited to conventional tile/slate roofs; both flat and corrugated sheet can be used instead of tiles or slates. Also, an all metal construction for the spars and purlins is feasible. There is therefore no reason why a steel framed building should not have a tra ditional tiled or slated roof affixed in accor dance with the invention.

In order that the invention be better under stood, an embodiment of it will now be de scribed by way of example with reference to the acompanying drawing in which the sole figure is a perspective view, partly in section, of part of a roof constructed according to the invention.

In the figure, a plurality of shallow metal channels 1 are attached together edge-to-edge to form in effect a single sheet with a series of upwardly-facing-edges 9. The channels are bolted to supporting metal purlins 3.

A number of timber battens 4 are provided, at intervals, each attached to additional pur lins. These battens carry a roofing felt 5, nor mal (transverse) slating/tiling battens 6, and the final outer surface of slates 7. The indivi dual channels 1 are filled with glass fibre mat 8.

1. A roof of the kind described, wherein at least some of the rafters are replaced by channel members attached together in side-by side relation with the major axis of each chan nel extending down the slope of the roof and with the outer part of the roof attached to the upstanding edge portions of said channels.

2. A roof according to Claim 1 wherein the spaces defined between the channel members and the outer part of the roof are filled with an insulation material such as glass fibre mat, or rigid foam insulation slabs.

3. A roof according to any preceding claim

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in and relating to roofing systems This invention relates primarily to roofing systems wherein the final, outer surface of the roof is to be tiled or slated, although a final surface based on cladding sheets or panels is also possible. Normal practice for roofs which are tiled or slated is for a supporting timber structure to be erected, comprising at least one main roofing purlin carrying a number of rafters which extend down the slope of the roof. Roofing felt is applied over the whole assembly, followed by battens to which the final surface layer of tiles, slates or sheet is then affixed, by nailing. Such roof constructions are very well-known; they need not be further described in detail. However, they have certain disadvantages, particularly where it is desired to enhance the thermal insulation properties by adding a layer of fibrous insulation material. This can be done by using an inner cladding of plasterboard, or a fire protection board, to support a fibrous mat in the spaces between the rafters and purlins. Unfortunately, any subsequent water penetration of the structure may be difficult to detect and/or locate, at least until signs of damp or even rot appear on the inner surface of the cladding. Also air circulation/natural ventilation) at the underside of the roof is very drastically reduced, which is in itself likely to promote fungal growth. Accordingly, it is more usual to provide a so-called false ceiling to carry the insulation layer, leaving a completely clear air space immediately adjacent the inside of the roof structure itself. This often results in at least some wasted space inside the building. According to the present invention,at least some of the rafters of a roof of the kind above described are replaced by channel members attached together in side-by-side relation with the major axis of each channel extending down the slope of the roof and with the outer part of the roof attached to the upstanding edge portions of said channels. Preferably, the spaces thus defined between the channel members and the outer part of the roof are filled with an insulation material such as glass fibre mat or rigid foam insulation slabs. Preferably all the conventional rafters are replaced by a series of channel members, the latter being supported entirely by the purlins, or by such purlins and additional purlins as may be needed to confer adequate resistance to bending of the channels. The channels are preferably of metal, for example, of cold formed galvanised steel. It is particularly advantages to use plastics coated metal in order to maximise resistance to corrosion. Where metal channels are used, these may be bolted or rivetted together through their upwardly-di rected edges. The latter may be profiled to overlap with adjacent edges so as to present an outwardly-facing (referring to the outer sur face of the roof) flat portion to which roofing felt and/or roofing battens can be attached by bolts, rivets and/or self-tapping screws. This arrangement is especially convenient because it results in a series of parallel, nar row flat strips extending down the roof slope and spaced apart by the width of a channel. These strips are of course each analogous to a conventional rafter. Because the sloping channel members are inherently adapted to be self-draining, even if water penetration occurs through the outer surface of the roof, it should not cause a sig nificant problem, in that adventitious water will not be able to soak into any timber, or plaster board inner lining. It will be appreciated that the invention just described has significant advantageous over the traditional timber roof construction.How ever, it is not limited to conventional tile/slate roofs; both flat and corrugated sheet can be used instead of tiles or slates. Also, an all metal construction for the spars and purlins is feasible. There is therefore no reason why a steel framed building should not have a tra ditional tiled or slated roof affixed in accor dance with the invention. In order that the invention be better under stood, an embodiment of it will now be de scribed by way of example with reference to the acompanying drawing in which the sole figure is a perspective view, partly in section, of part of a roof constructed according to the invention. In the figure, a plurality of shallow metal channels 1 are attached together edge-to-edge to form in effect a single sheet with a series of upwardly-facing-edges 9. The channels are bolted to supporting metal purlins 3. A number of timber battens 4 are provided, at intervals, each attached to additional pur lins. These battens carry a roofing felt 5, nor mal (transverse) slating/tiling battens 6, and the final outer surface of slates 7. The indivi dual channels 1 are filled with glass fibre mat 8. CLAIMS

3. A roof according to any preceding claim wherein the channel members are of metal.

4. A roof according to any preceding claim wherein the upstanding edges of the channels are profiled to overlap with adjacent channel edges so as to present an outwardly-facing flat portion to which roofing felt and/or roofing battens can be attached.

5. A roof construction substantially as described with reference to and as illustrated by the accompanying drawing.