GB2252337A

GB2252337A - Roofing construction

Info

Publication number: GB2252337A
Application number: GB9101409A
Authority: GB
Inventors: Peter Taylor
Original assignee: TALFAB ARCHITECTURAL METALWORK
Current assignee: TALFAB ARCHITECTURAL METALWORK
Priority date: 1991-01-22
Filing date: 1991-01-22
Publication date: 1992-08-05
Anticipated expiration: 2011-01-22
Also published as: GB2252337B; GB9101409D0

Abstract

A standing scam (13) is created by the interengagement of respective differently shaped first edge and second edge portions (11, 12) of two sheets each of which has opposite edge portions of the two different shapes. The interengagements of the differently shaped edge portions (11, 12) not only facilitates the anchoring of the standing seam (13) to a structural support (e.g. a rafter) by way of a fixing clip (10) which is secured to the support but also creates a large chamber (27) into which water can penetrate during a torrential downpour by way of a joint (28) which also provides a means through which water can seep out after the downpour conditions have ceased to exist. <IMAGE>

Description

ROOFING CONSTRUCTION This invention relates to a roofing construction.

When using sheeting or planks made of, for example, roll-formed aluminium, to make or complete a roof whose pitch is small (namely, down to as little as pitch), there are considerable problems to be overcome in trying to provide weatherproof seals between the constituent pieces of sheeting or planks; said pieces or planks are normally cut to a length to suit the roof in question and the edges of said pieces of sheeting or planks are connected to one another at a slight overlap.

Constructions are in widespread use which include so-called anti-capillary grooves which are created by appropriate forming of the one edge or edge portion of each sheet and thereafter bringing together the one edge of a first sheet and the other edge of a second sheet. In one such construction there is an additional so-called seepage channel; any water which penetrates into this seepage channel is able to run down the channel (in a direction parallel to the edges of the first and second sheets) towards the lower end thereof and out into, presumably, guttering.

In another such construction, the interengagement of the overlapping edges or edge portions of any two sheets is such, according to the description and illustration thereof in sales literature, that a channel is formed, internally of the standing seam, which is capable of acting as a seepage channel which can only empty out by the water behaving in the same manner as described at the end of the preceding paragraph. There is no other way out for the water.

The present invention consists in a roof construction which includes at least two metal sheets whose respective first edge portions are identical with one another and whose respective second edge portions are identical with one another, the first edge portion of one of said sheets being so interengaged with the second edge portion of the other or another of said sheets as to form a standing seam which not only embodies an enlarged anti-capillary chamber whose open lower end debouches into the ambient atmosphere but also embodies drainage means capable of assisting the emptying of said chamber when the flood-water level is lower than said drainage means.

In a roof construction as described in the preceding paragraph, the uppermost part of the first edge portion of said one of said sheets is in contact with the inside surface of the uppermost part of the second edge portion of the other or another of said sheets, said drainage means being formed by a tight joint which is created by the physical contact between a part, including the free edge thereof, of said second edge portion of the other or another sheet and another part of said first edge portion remote from said uppermost part of said first edge portion, said tight joint being at a level lower than said enlarged anti-capillary chamber.

The present invention further consists in a roof construction which includes at least two metal sheets which have identical respective first edge portions and identical respective second edge portions, the first edge portion of one of said sheets overlapping and being so interengaged with the second edge of the other or another of said sheets as to form a standing seam, all constructed, arranged and adapted to operate substantially as hereinafter described with reference to and as illustrated in the accompanying diagrammatic drawings, in which : Figure 1 illustrates a section through a standing seam at a fixing clip; Figure 2 illustrates the same section as Figure 1 but with indications of the behaviour of the standing seam under flood conditions; and Figure 3 illustrates the cross-sectional shapes of the opposite edges of each sheet used.

One or more polypropylene or other suitable fixing clips 10 are firmly secured(at spacings which, typically, can be at 1.5 to 2.5 m centres) to a rafter or other structural support (not illustrated) and two metal sheets 11, 12 with appropriately formed edges or edge portions, which are interengaged, are caused to engage said fixing clip 10. The result is a standing seam which is indicated by the reference numeral 13.

One edge or edge portion of the sheet 11 is bent upwardly (as seen in the drawings, particularly in Figure 3, and in relation to the plane which contains the major proportions of said sheets 11,12) to form a web portion 14, thereafter in a double bend to form an S-shaped portion 15, whose end is connected to a substantially straight web 16. The end of the web 16 is connected to a web 17 which is normal to the web 16 and which terminates in a small horizontal part 18.

The sheet 12 also has one edge or edge portion which is formed as described in the preceding paragraph but said edge or edge portion of the sheet 12 is not shown. However, the other edge or edge portion of said sheet 12 is shown and is firstly bent upwardly to form a web 19 and is then so bent as to form a stiffening rib 20. The edge or edge portion continues in a generally upwards direction in a web 21 which is connected to a web 22 which is,in turn, connected to a web 23. At the lower edge of the web 23, the material is formed into a channel-shaped terminal portion 24 which, in shape, complements the stiffening rib 20.

The sheet 11 has another edge or edge portion (not shown) which is identical with that described in the preceding paragraph.

The above-described formation of the respective opposite edges or edge portions of the two sheets 11, 12 enables them to be overlapped and interengaged, and also enables them to engage or to be engaged by the fixing clips 10. Thus, a nose 25 of the clip 10 engages the re-entrant cavity which results from the formation of the stiffening rib 20 and a nose 26 of said clip 10 extends into the Sshaped portion 15.

The small horizontal part 18 is connected to the vertical web 17 which is connected to the horizontal web 16. The web 16 sits on the top of the clip 10 and the part 18 is in contact with the inside surface of the web 22 of the edge or edge portion of the sheet 12. This provides support for said web 22 and therefore increases the rigidity or strength of the standing seam.

The interengaged edges/edge portions of the sheets 11, 12 create a chamber 27 into which water can penetrate by way of the tight joint which is indicated by the reference numeral 28. In conditions of torrential downpour which may lead to the roof becoming severely flooded, the water can build up inside the chamber 27 as shown in Figure 2 but such water will flow down the gradient until it debouches into, for example, guttering at the lower roof edge.

When the flood level subsides and becomes lower than that of the web 16, the water can also start to seep out of the chamber 27 by way of the tight joint 28.

This doubling of the drainage capability by enabling water to get out by way of the same passageway as enabled it to get into the standing seam is an important feature of the roofing construction according to this invention.

Claims

CLAIMS:

1. A roof construction which includes at least two metal sheets whose respective first edge portions are identical with one another and whose respective second edge portions are identical with one ano-ther, the first edge portion of one of said sheets being so in-terengaged with the second edge portion of the other or another of said sheets as to form a sanding seam which not only embodies an enlarged anti-capillary chamber whose open lower end debouches into the ambient atmosphere but also embodies drainage means capable of assisting the emptying of said chamber when the floodwater level is lower than said drainage means.

2. A roof construction as claimed in Claim 1, wherein -the uppermost part of the first edge portion of said one of said sheets is in contact with the inside surface of the uppermost part of -the second edge portion of the other or another of said sheets, said drainage means being formed by a tight joint which is created by the physical contact between a part, including the free edge thereof, of said second edge portion of the other or another sheet and another part of said firs-t edge portion of said one of said sheets remote from said uppermost part thereof, said tight joint being at a level lower than said enlarged anti-capillary chamber.

3. A roof construction which includes at least two metal sheets which have identical respective first edge portions and identical respective second edge portions, the firs edge portion of one of said sheets overlapping and being so interengaged with the second edge of the other or another of said sheets as to form a standing seam, all constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying diagrammatic drawings.

4. Any features of novelty, taken singly or in combination, of the embodiment(s) of the invention hereinbefore described with reference to the accompanying daigrammatic drawings.