Flashing for corrugated roofing

Abstract

 A flashing for covering the transition between corrugated roofing (1) and an adjacent building structure (2) is composed of two layers (8; 4) of sheet material. The lower layer (8) is composed of a rather rigid and relatively non-deformable roofing material whereas the upper layer (4) is made up of a plastic deformable material which is already used as flashing. The lower layer is provided as a strip (8) with a continuous region (12) and an adaptable region (11) with slits (9) that makes the otherwise non-deformable strip (8) conform to the crests (1') and troughs (1") of the roofing (1). The continuous region (12) will provide a flat support means for providing an approximately plane region (7) of the upper layer (4) close to the structure (2), thus avoiding hollows or depressions that otherwise are formed at the transition between roofing (1) and building structure (2).

Description

Field of the Invention

[0001] The present invention concerns a flashing for corrugated roofing provided at the transition between the roofing and a protruding building structure, e.g. a chimney, a frame of a skylight, a wall or the like. The invention also concerns a method for establishing such a flashing.

Background of the Invention

[0002] Flashings have been used for centuries in order to render watertight the transition between building structures and the adjacent roofing. Previously, lead in sheet form was widely used, but has been banned for health considerations, and other pliable and deformable materials are now used.

[0003] When applying flashings to corrugated roofing there is the problem of depressions in the flashing close to the building structure. The flashing is adapted to the contour of the wavy roofing, producing crests and troughs similar to those of the roofing. When the flashing is adapted to the straight or non-wavy building structure, there will be a border area where the wavy contour is transformed to another shape, often a flat or straight surface. At the transition, a concave contour like a hollow or depression will be produced where rainwater can be collected. This is undesirable as any crack in the flashing material, possibly produced by mechanical working or even walking on the roof, will cause the water to leak into the building at the transition. Furthermore the presence of water (liquid) will even for so-called non-corroding materials cause deteriation of the material, due to the waters influence, often mixed with corrosive pollutants stemming from the air, such as for example exhaust fumes etc.

Object of the Invention

[0004] The object of the invention is to relieve the problems of the prior art and to provide a flashing without hollows or depressions at the transition between a corrugated roof and a non-wavy building structure. It is also the object of the invention to provide a flashing ing which can withstand mechanical action on its upper and outer surface without yielding or cracking.

Description of the Invention

[0005] The flashing according to the invention is peculiar in that the flashing includes a second layer of sheet material which is substantially non-deformable and disposed under the first, plastically deformable material and in use over the roofing or structure, and that the second layer of sheet material in use is attached to the top of the crests of the corrugated roof in a region adjacent to the structure, at least part of the second layer extending across the top of the crests so as to form a substantially plane area on the crests in the region adjacent to the building structure.

[0006] The method for establishing a flashing according to the invention uses an outer layer of plastically deformable watertight sheet material and an inner layer of a substantially non-deformable sheet material, the method including the steps:

a) placing and attaching a strip or section of non-deformable sheet material on crests of the corrugated roofing so as to establish a substantially plane area of the inner layer of non-deformable sheet material adjacent to the building structure;

b) applying the outer layer plastically deformable watertight sheet material at the transition between the roofing and the building structure so as to cover the strip or section of non-deformable sheet material entirely.

[0007] By providing a piece of a rigid and substantially non-deformable sheet material under the pliable and plastic deformable material conventionally used, it is possible to provide an approximately flat area in a region close to and adjacent to the building structure. Thereby, a hollow or depression is avoided, and water coming from above down a corrugated roof cannot be collected in the region close to the building structure. The second layer of non-deformable material is preferably laid directly on the roofing on the one hand with the deformable first layer directly in contact with the first layer, but embodiments with additional layers are possible within the scope of the invention. Similarly, an additional layer between the second deformable layer and the roofing is possible within the scope of the invention.

[0008] The piece of non-deformable material may simply be a rectangular strip or section, and the transition between the flat region produced by the non-deformable material and the corrugated roof may be covered by the layer of deformable material.

[0009] However, a more smooth transition can be achieved in a preferred embodiment of the flashing according to the invention wherein the second layer of sheet material is provided as a section or strip including an adaptable region at a side edge facing away from the building structure, the side edge provided with a plurality of slits extending a length from the side edge into the adaptable region, the dimension and spacing of the slits being such that the adaptable region can fit closely to the crests and troughs of the corrugated roofing. The slits are provided with appropriate spacing so that a series of relatively narrow strips are formed which will have a certain flexibility. The strips thus formed will make the slit region adaptable to the crests and troughs of the adjacent roofing, thereby forming a smooth transition from the corrugated roofing to the flat part of the non-deformable area. The smooth transition formed by the adaptable region of the non-deformable sheet material will form more mechanically rigid base for the deformable top layer of sheet material, increasing the strength and durability of the latter.

[0010] Consequently, in a preferred embodiment of the method according to the invention, the strip or section of the inner layer of non-deformable sheet material prior to application on the roof is provided with a plurality of slits in a region extending a length from a side edge on the section or strip, the dimension and spacing of the slits being such as to provide an adaptable region for closely fitting to the crests and troughs of the corrugated roofing, where the strip or section of non-deformable sheet material is positioned on the roofing such that free side edge bordering the adaptable region faces away from the building structure.

[0011] It is preferred that the attachment of the second layer of sheet material to the crests is provided by bonding, e.g. by glue. Furthermore, it is preferred the second layer of material is made of a synthetic material based on PVC.

Description of the Drawing

[0012] Embodiments of the invention are described in more detail with reference to the drawing, in which:

Fig. 1

shows a sectional view of an example of a prior art flashing;

Fig. 2

shows a sectional view of a first embodiment of a flashing according to the invention;

Fig. 3

shows a sectional view of a second embodiment of a flashing according to the invention;

Fig. 4

shows a plan view of a strip of a non-deformable sheet material used in the second embodiment of the invention; and

Fig. 5

shows the same as Fig. 4, but in perspective view and laid upon a corrugated roofing.

Detailed Description of Example Embodiments

[0013] In Fig. 1 showing a prior art flashing on a corrugated roofing 1, a building structure like wall or chimney is designated by the number 2 and a roof batten by the number 3. The layer of flashing material 4 is known per se and has to be watertight, weather-resistant and deformable in a plastic manner so that a sheet of the material can adapt itself to the contour of the roofing 1 when pressed down into the troughs of the roofing 1 and stay permanently deformed. The flashing 4 may be of Perform™, a synthetic sheet material of composite nature, e.g. with a metal wire mesh embedded in the material, but other materials may be applicable.

[0014] It appears from Fig. 1 that the flashing 4 covers the gap between the corrugated roofing 1 and the structure 2 and that the adaptability of the flashing 4 produces a hollow 5 close to the structure 2. Rain water will be collected here without possibly of draining since the crests 1' of the roofing form barriers at the sides. Any cracks in the material 4 will cause water to leak down into the underlying building construction.

[0015] In a first embodiment of the invention, a relatively rigid strip of non-deformable sheet material 6 is glued to the crests 1' of the roofing 1, thus forming a flat and almost plane basis close to the building structure 2 on the top of the crests 1'. After that, the deform-formable top layer of deformable sheet material 4 is applied on top of the sheet material 6 while following the contour of the structure 2, the strip of sheet material 6 and the crests 1' and troughs 1" of the roofing 1, respectively. It appears from Fig. 2 that the layer designated 6 now produces a flat region 7 close to the structure 2. Although an internal comer is present at the transition between the roofing 1 and the structure 2, any water is now allowed to flow to the sides and be drained off in the usual way in such roof constructions. Furthermore, the top layer 4 of deformable material can now form an approximately horizontal section between the flat region 7 and the area at the bottom of a trough 1" so that water will not tend to be collected here, but flow away to the region 7 and be drained off to the sides in the way known in the industry.

[0016] In a second embodiment of the invention appearing on Fig. 3, the non-deformable layer of sheet material is provided as a strip 8 which is wider and provided with a plurality of slits 9 transversely to one side edge 10, cf. Fig. 4, thus forming an adaptable region 11 of flexible lamellae even though the material of the strip is a rather rigid sheet material. A plan view of the strip 8 before being applied is seen on Fig. 4 with adaptable region 11 and unbroken region 12. Fig. 5 shows the strip 8 when placed on a corrugated roof made of artificial tiles 1, where it appears that the adaptable region 11 with slits 9 accommodates to the contour of the tiles whereas the continuous region 12 stays flat and almost along a plane between the three crests 1' upon which the strip 8 lies.

[0017] After laying the layer or strip 8 of non-deformable material at the position shown on Fig. 3 and gluing the strip 8 to the crests 1' of the roofing, the upper layer 4 of deformable material is applied in the way known per se as the top layer of the flashing. For the sake of clarity, the edge 13 of the layer 4 is shown ending on the open face of the roofing 1 while in practice this edge 13 will often be sealed or inserted between overlying tiles or roof plates for the sake of tightness. The upper layer 4 is now mechanically supported by the underlying sheet or strip 8 of slit region 11 of non-deformable sheet material, evening the transition between the flat region 7 and the contours of the roofing 1 and additionally providing strength to the finished flashing.

[0018] The material used for the non-deformable sheet material 6, 8 is preferably a PVC-based roofing material, e.g. of the trademark Sika, or other materials with the same properties.

[0019] The claims cover embodiments other that those described above. Attachment of the strip of non-deformable material can be effected by other means than gluing, e.g. by fasteners of various kinds. Also, other kinds of sheet material for the flashing can be used if only they fulfil the requirements to plastic deformability and rigidity as described above.

Claims

1. A flashing for corrugated or wavy roofing materials provided at the transition between the roofing material and a protruding building structure, e.g. a chimney, a frame of a skylight, or a wall, where said flashing comprises an outer layer of a watertight sheet material which is plastically deformable, characterised in that the flashing includes a second layer of sheet material which is substantially non-deformable and disposed under the first, plastically deformable material and suitable to be positioned over the roofing material or structure, and that the second layer of sheet material in use is attached to the top of the crests of the corrugated roof in a region adjacent to the structure, at least part of the second layer extending across the top of the crests so as to form a substantially plane area on the crests in the region adjacent to the building structure.

2. Flashing according to claim 1, wherein the second layer of sheet material is provided as a section or strip including an adaptable region at a side edge in use facing away from the building structure, the adaptable region being provided with a plurality of slits extending a length from the side edge into the adaptable region, the dimension and spacing of the slits being such that the adaptable region can fit closely to the crests and troughs of the corrugated roofing.

3. Flashing according to claim 1 or 2, wherein the attachment of the second layer of sheet material to the crests is provided by bonding, e.g. by glue.

4. Flashing according to any preceding claim, wherein the second layer of material is made of a synthetic material based on PVC.

5. Flashing according to any of claims 2 to 4, wherein the outer layer and the second layer are at least partly connected outside the adaptable region.

6. A method for establishing a flashing according to claim 1 for corrugated or wavy roof structures provided at the transition between the roofing and a building structure, e.g. a chimney, a skylight, or a wall, using an outer layer of plastically deformable watertight sheet material and an inner layer of a substantially non-deformable sheet material including the steps:

a) placing and attaching a strip or section of non-deformable sheet material on crests of the corrugated roofing so as to establish a substantially plane area of the inner layer of non-deformable sheet material adjacent to the building structure;

b) applying the outer layer of plastically deformable watertight sheet material at the transition between the roofing and the building structure so as to cover the strip or section of non-deformable sheet material entirely.

7. A method according to claim 6, wherein the strip or section of the inner layer of non-deformable sheet material prior to application on the roof is provided with a plurality of slits in a region extending a length from a side edge on the section or strip, the dimension and spacing of the slits being such as to provide an adaptable region for closely fitting to the crests and troughs of the corrugated roofing, where the strip or section of non-deformable sheet material is positioned on the roofing such that the side edge bordering the adaptable region faces away from the building structure.

8. A method according to claim 6 or 7, wherein the inner layer of sheet material is attached to the crests by bonding, e.g. by glue.

Drawing