GB2241975A - Support section for roofing system comprising channel for draining water which penetrates the seal - Google Patents

Abstract

A roofing system is disclosed which comprises a plurality of elongate sloping support elements for supporting the edges (38) of one or more sloping roofing panels (36), each panel edge being capped by an elongate capping strip (40) sealed against that edge and secured to the respective support element (30). Each support element is formed with a channel (31) to allow water which penetrates the seal between the cap and the panel edge to flow downwardly along the support element. In a particular arrangement including a roof valley where two pitched roof portions meet at and are supported by an inclined valley beam, the channeled support elements are inclined rafters intersecting the valley beam at their lower ends. The valley beam is formed with a channel, and is joined to the rafters so that the valley beam channel communicates with the rafter channels for receiving the water flowing out of the rafter channels at their lower ends. <IMAGE>

Description

ROOFING SYSTEM AND SUPPORT SECTION THEREFOR This invention relates to a roofing system in which roofing panels span between and are secured along their edges to sloping rafter beams to create a pitched roof covering. The invention is particularly, but not exclusively, concerned with pitched roofing systems having transparent or translucent roof panels, as used in conservatory extensions.

Conservatory extensions are very popular nowadays, and there is currently a preference for "period" designs using traditional building materials.

Accordingly, the structural wall framework for such conservatory extensions is commonly made from Limber, favoured kinds of timber being mahogany, and Swedish redwood, with the roof support structure normally made from cedarwood.

Conservatory roofs normally comprise a number of panels of glass or suitable transparent or translucent plastics material, spanning between and secured at their edges to the sloping rafters of a suitable rafter system. For example, Fig. 1 illustrates a typical traditional conservatory design having a glazed roof which in this instance includes a simple pitched roof portion 1 with glazing panels sloping from a straight ridge 2 to a parallel straight eaves 3, and a roof portion 4 comprising pitched triangular roofing panels each sloping downwardly from a roof peak 5 to a respective eaves portion 6.In each of the roof portions 1 and 4, each glazing panel is supported at its downwardly sloping side edges on respective sloping rafters, and the conventional arrangement for securing the panel edges is illustrated in the sectional view of Fig. 2, taken on line Il-Il of Fig. 1.

With reference to Fig. 2, the adjacent sloping edges of two adjacent glazing panels 7 are supported on respective opposite upper edge surfaces 8 of a sloping rafter 9. A strip-like timber cap 10 is screwed onto a central elongate ridge 11 projecting upwardly relative to the surfaces 8 to cover the edges of the panels 7 from above. Weather-sealing of the panel edges is provided by sealing strips 12 fitted into elongate grooves formed in the surfaces 8, and contacting the underneath surface of the panels along their edges, and similar sealing strips 13 fitted into grooves formed in the underside of the cap 10 along its edges and contacting the upper surfaces of the panels 7 along their edges.

Although under normal weather conditions the arrangement shown in Fig. 2 provides adequate sealing of the panel edges, it has been found that in more severe weather conditions, particularly where rain is driven hard against the seal between the sealing strips 13 and the panel 7 as shown by the heavy arrow A, water penetration past the seals 13 and 12 tends to occur, resulting in seepage onto the inside face of the rafter, as shown at B.

This seepage is clearly undesirable, and the present invention seeks, in one aspect, to alleviate this problem by providing a roofing system comprising a plurality of elongate sloping support elements for supporting the edges of one or more sloping roofing panels, each panel edge being capped by an elongate capping strip sealed against that edge and secured to the respective support element, each said support element being formed with a channel to allow water which penetrates the seal between the cap and the panel edge to flow downwardly along the support element.

With this arrangement, the penetrating water can be conveyed down to a main gutter provided at the eaves of the roofing system. Thus, each support element itself acts as a kind of feeder gutter for the penetrating water.

Complex roofing systems often include one or more roof "valleys", each of these being the line where the respective planes of two adjacent sloping roof portions meet. The supporting structure of the roof system will include, at each of these valleys, a sloping valley beam which will normally intersect at least one of the sloping rafters of each roof portion.

A simple example of such an arrangement is illustrated schematically in Fig. 3, in which a valley beam 20 provided at the intersection of two sloping roof portions 21 and 22 is intersected by a rafter 23 of the roof portion 21, and a rafter 24 of the roof portion 22.

If each of the rafters 23 and 24 is channeled, in accordance with the present invention, the water flowing down the channels in these rafters can be collected and directed down to the main roof gutter by providing suitable channel means in the inclined valley beam, and by constructing the joints between the valley beam and the rafters so that the valley beam channels communicate with the rafter channels and receive the rain water flowing down the latter.

In a described embodiment, in which the supporting structure for the roof panels is made of timber or a timber-like material which has similar physical properties and characteristics and can be worked in the same way as timber, the jointing arrangement between the inclined rafters and the inclined valley beam is such that the upper part of the rafter formed with the drainage channel or channels projects through the thickness of an outer wall of the corresponding drainage channel in the valley beam, so that the rain water draining along the rafter can pour directly into the drainage channel in the valley beam.

Another problem in conventional conservatory roofing systems is that rain water accumulates into small pools at the positions P shown in Fig. 3 between the strip cappings on the valley beam at 20 and on the intersecting rafters 23 and 24. In accordance with a preferred additional feature of the present invention, gaps are provided alongside the capping strip fixed to the valley beam at its intersection with similar capping strips on the inclined rafters to facilitate draining of the water which would form these pools into the drainage channels of the rafters, and thence into the drainage channels of the valley beam.

It will be appreciated from the above, and from the following detailed description, that the underlying concept of the present invention resides in the adaptation of the sloping roof support elements, such as the rafters and/or valley beams, so as to act as gutters down which penetrating rain water can flow.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which are given by way of illustration only, and in which: Fig. 1 is an elevational view of a conservatory extension including a glazed roofing system; Fig. 2 is a transverse sectional view through a sloping rafter of a conventional glazed roofing system showing how glazing panel edges are sealed; Fig. 3 illustrates schematically part of a support structure in a roofing system where two roofing portions intersect at a valley; Fig. 4 is a transverse cross-sectional view through a rafter assembly of a roofing system according to the present invention, showing its seal to adjacent glazed roofing panels; ; Fig. 5 is a transverse cross-sectional view illustrating the jointing arrangement between inclined rafters and an inclined valley beam, in accordance with the present invention, and Fig. 6 is a part-section, part-cutaway perspective view illustrating the jointing arrangement between an inclined rafter and an inclined valley beam, in accordance with the present invention.

With reference to Fig. 4, there is shown in cross-section a rafter assembly which is used in a manner analogous to the assembly shown in Fig. 2 for supporting the parallel adjacent edges of two adjacent roofing panels in a glazed roofing system, for example for a conservatory extension. The cross-sectional configuration of a timber rafter 30 is adapted so as to provide two parallel drainage channels 31 extending along the rafter, and separated by a central elongate wall portion 32. Outer wall portions 33 of lesser height than the central wall portion 32 define the outer walls of the channels 31. Each outer wall portion 33 is grooved so that it can receive a barbridged securing rib 34 formed on the back of a respective lower sealing strip 35.The adjacent edge portions 38 of the two adjacent glazing panels 36 are supported on the respective sealing strips 35, these edge portions 38 of the panels projecting only CL little way inwardly of the side walls 33. An elongate timber capping strip 40 is secured by suitable fixing elements eg screws 41, to the central wall portion 32, and two elongate upper sealing strips 44 are secured to the underside of the capping strip 40 adjacent its lateral edges by the same fixing technique as for the sealing strips 35, namely by means of barb-ridged securing ribs 45 formed on the back of the strips 44 received in fixing grooves 46 of the capping strip.

As illustrated in Fig. 4, in the event of rain water being directed with excessive force, eg. during storm conditions, in the direction A against the outer edges of the sealing strips 44, resulting in rain penetration through the gap between the seal 44 and the upper face of the glazing panel 7, the penetrating rain water can drip into the channel 31 and flow downwardly under the effect of gravity along the channel 31 in the inclined rafter. In this way, the water is conveyed away from the point or points of penetration, and will therefore not seek to penetrate the lower seal 35.

In the case of an inclined rafter such as the rafter 50 of Fig. 1 leading directly to the roof eaves, the arrangement may be such that the water flowing downwardly inside the rafter simply pours out of its lower end into the main eaves gutter 51.

However, in the case of an inclined rafter which intersects a valley beam, a preferred arrangement as illustrated in details in Figs. 5 and 6 is preferred.

In the illustrated arrangement, the rafter 60 extends between a horizontal pole plate 61 fixed against the brickwork 62 of a building. The rafter 60 is joined at its lower end to an inclined valley beam 64 which, like the rafter, is formed with a crosssection providing two drainage channels 65 separated by a central relatively high wall portion 66, with outer, relatively low wall portions 67 defining the outer walls of the channels 65. Each side wall portion 67 of the valley beam is grooved on its top to receive the back securing rib 70 of a sealing strip 71 which seals against the edge portion of a roofing panel where it is supported on the valley beam.A capping strip 73 is secured by fixing elements, such as screws, to the top of the central wall portion 66, and is grooved on its underside along its lateral edges to receive the back securing ribs 74 of sealing strips 75 which seal on top of the edges of the roofing panels 7. These sealing strips 75 also contact the top of the central wall 32 at the end of the rafter 60 where it joins the valley beam, as can clearly be seen in Fig. 5.

As can be seen from Figs. 5 and 6, the end of the inclined rafter 60 is undercut so as to provide a flat face 76 which abuts the side face 77 of the valley beam, and an upper part of the rafter, including the ends of the drainage channels 31, forming an extension 78 which projects through a rectangular opening cut in the side wall 67; this opening has an inclined lower edge 80 on which the underside of the extension 78 is seated. In this way, this extension 78 of the upper part of the rafter projects through the thickness of the outer wall portion 67 of the drainage channel 65 in the valley beam 64, so that the rain water draining along the rafter 60 pours directly into the drainage channel 65 in the valley beam. Since the valley beam is itself inclined, the rain water pours down the channel 65 to the main eaves gutter.

Furthermore, rainwater which may penetrate underneath the sealing strip 75 will simply flow over the lower edge of the roofing panel lying underneath the capping 73 into the drainage channel 65 where it will join or be joined by any water flowing into this channel from the channel 31 of the rafter 30.

As can be seen from Fig. 5, the timber section used for the capping strip 40 and 73 is such as to provide small gaps 85 alongside the capping strip 73 at its intersections with the capping strips 40 on the inclined rafters. These gaps 85 allow rain water, which would otherwise accumulate at the positions P shown in Fig. 3 so as to form pools just above the intersections between the valley beam and the rafters, to drain over the corner (which has been cut away in Fig. 6) of the roofing panel into the lower end of the channel 31, and thence into the main drainage channel 65 in the valley beam.

At its upper end, the rafter 60 is undercut for abutment with the forward face 90 of the pole plate 61, an extension 91 thereby formed at the upper part of the rafter projecting through an opening cut through the thickness of a relatively low forward wall portion 92 of a collection channel 93 formed in the top of this pole plate 61. A relatively high rear wall 94 at the top of the pole plate 61 is surmounted by a purpose-made angle fillet strip 95 across which a lead flashing strip 96 extends, with the upper ends of the cappings 40 extending over the top of this flashing 96 as shown to hold it fixed. This channel 93 serves only to collect condensation which may form on and drip from the underside of the lead flashing.

Channel stoppers 97 inserted in the upper ends of the channels 31 in the rafters 60 prevent any water backflowing up and along such channels 31 under severe wind pressure from entering the collection channel 93.

The small amount of condensation in the channel 93 will evaporate harmlessly without causing any damage to the timber of the poll plate 61.

It will be understood that in the system described above both the rafters and the valley beam act as feeder gutters for conveying the rain water which penetrates underneath the sealing strips downward and eventually to the main eaves gutter.

Claims (10)

CLAIMS:

1. A roofing system comprising a plurality of elongate sloping support elements for supporting the edges of one or more sloping roofing panels, each panel edge being capped by an elongate capping strip sealed against that edge and secured to the respective support element, each said support element being formed with a channel to allow water which penetrates the seal between the cap and the panel edge to flow downwardly along the support element.

2. A roofing system according to claim 1 wherein at least one of said support elements is formed with two parallel elongate wall portions which support the parallel edges of two adjacent said roofing panels, and with two parallel elongate said channels between said two wall portions, said capping strip being positioned over said channels and sealed along its opposite edges against said parallel edges of the adjacent roofing panels.

3. A roofing system according to claim 2 wherein said at least one support element is also formed with an elongate central wall portion between said channels and wherein said capping strip is secured by means of fixing elements fixed into said central wall portion.

4. A roofing system according to any preceding claim wherein the channelled support element is an inclined rafter positioned with its lower end adjacent an eaves gutter for directing the downwardly flowing water into said gutter.

5. A roofing system according to any of claims 1 to 3 which includes a roof valley where two pitched roof portions meet and an inclined valley beam supporting the roof portions at said valley, and wherein the channelled support element is an inclined rafter which intersects said valley beam at its lower end, said valley beam also being formed with a channel and being joined to said rafter so that the valley beam channel cDmmunicates with the dafter channel for receiving the water flowing out of the rafter channel at said lower end.

6. A roofing system according to claim 5 wherein a part of said rafter including said channel projects through the thickness of an outer wall portion of the channel in said valley beam so that water draining along the rafter pours directly into said valley beam channel.

7. A roofing system according to claim 5 or claim 6 wherein there is provided a further capping strip secured to the valley beam and sealed against the lower edge of a said roofing panel, and wherein a gap is provided alongside the further capping strip at its intersection with the capping strip of the inclined rafter to allow water which flows downwardly on the panel surface toward the intersection, to flow into the lower end of the rafter channel and thence into the valley beam channel.

8. A roofing system according to any preceding claim wherein each support element is made of timber or of a timber-like material.

9. A roofing system substantially as hereinbefore described with reference to any of figures 4 to 6 of the accompanying drawings.

10. A timber section support element for a roofing system according to any preceding claim.