LEADFREE ROOF FLASCHING MATERIAL

Abstract: A leadfree plate-shaped roof flashing material comprises a sandwich structure in which a stress damping and stabilizing layer (1) of ductile material is completely covered on one side and at least partly covered on the other side by preferably metallic foil sheetings (2, 3), e.g. of aluminium foil, designed with densely positioned flattened folded sections (4) having such a form, e.g. as closed inverted pleats, that the extreme material layer (4a) of each folded section gets into contact with the stress damping and stabilizing layer (1) only when the folded sections open in connection with deforming the flashing material to make it fit to the roofing.

Description: eadfree roof flashing material. The invention relates to a leadfree plate-shaped roof flashing material having a sandwich structure including a preferably metallic foil and a stress damping and stabilizing layer of ductile material. Such flashing materials in the form of plate members or skirts are used in the manufacturing of sealed joints between the main frame of a window installed in an inclined roof and the surrounding roofing, in particular as a skirt-shaped flashing at the lower horizontal member of the main frame. Such materials have traditionally been constit¬ uted by lead plates of a thickness of appr. 1 mm, whose deformability to follow the shape of the roofing has frequently required hammering, thereby involving the risk of cracks and breakages. From Danish Patent Specifications Nos 148 064 and 145 509 and Danish Patent Application No. 5059/89 designs of flashing materials are known in which said drawback has been remedied, so that the flashing material is much deformable by manual processing either by wave corrugation of the material or by designing it with parallel flattened, spaced apart folded sections and for instance with wave corrugation of the material between the folded sections. In order to avoid the economical and environ¬ mental problems involved by the traditional use of lead in flashing materials, the above referenced Danish Patent Specifications suggest leadfree sandwich struct¬ ures consisting of thin metal foil, preferably alumi- niu foil and a pressure adhesive coating, e.g. of bitumen. This sandwich structure is manufactured in a flat condition, following which the structure is cor¬ rugated in an omega-like waveform, the cross-sectional dimension of each curve being larger than the width of the slit aperture of the curve. As regards roofings in the form of undulated tiles with very deep troughs it has turned out to be difficult, even with these wave-corrugated designs, to obtain a sufficiently manual deformability to enable snap-fit interlocking between the flashing and roofing, and irrespective of the intended purely manual deform- ability it has frequently been necessary to undertake processing with a press tool or a hammer tool. As a consequence, the suggested leadfree flash- ing materials have had difficulty in gaining a footing in the market as a competitive and equal alternative of lead flashings and this has instead resulted in efforts to improve such flashings through wavepleated or folded designs, in which the lead thickness has been reduced, and attempts have been made to provide a good weather¬ proofness of the flashing by painting or lacquering. The above mentioned disadvantages associated with prior art flashing materials are substantially eliminated by the present invention through a leadfree design that is characterized in that the stress damping and stabilizing layer is completely covered on one side and at least partly covered on the other side by a foil sheeting formed with flattened folded sec¬ tions of such a shape that the extreme layer of each folded section gets into contact with the stress damp¬ ing and stabilizing layer only when the folded sections open in connection with deforming the flashing material to make it fit to a roofing. As distinct from the above referenced prior art sandwich structures, it is only the foil sheetings of the flashing material according to the invention that are provided with said densely positioned folded sec¬ tions. In the undeformed condition of the flashing material the stress damping and stabilizing layer located between the foil sheetings is merely in contact with the inwards facing layers of each folded section. When the flashing material by adaptation to an undul¬ ated roofing is being deformed the folded sections however open and the stress damping and stabilizing layer is being stretched and getting into adhering con¬ tact with the outwards facing layers of the folded sec¬ tions now opened. To obtain this function it is according to the invention preferred that the stress damping and stabil- izing layer is made from a material of a stretchable adhesive consistency in the relevant range of temper¬ ature, e.g. between -5 β C and 60"C. In a preferred embodiment the foil sheetings are folded in densely positioned, substantially closed inverted pleats. The foil sheetings may advantageously according to the invention be made from aluminium foil having a thickness of a magnitude from 0.1 to 0.5 mm. In an embodiment in which the stress damping and stabilizing layer is completely encapsulated between two foil sheetings, one of which has apertures or per¬ forations in the outwards facing parts of the inverted pleats, an improved adhesion to the underlying roof is obtained. An embodiment of the roof flashing material suitable for industrial production is according to the invention characterized in that the foil sheetings are continuous and folded along a folding line perpendicul¬ ar to the folded sections about the stress damping and stabilizing layer while the sheetings of the folded foil web are squeezed together along the remaining lateral edges. The invention will now be explained in detail with reference to the drawings, in which Figs 1 and 2 are two perspective illustrations partially in a sectional view of an embodiment of a plate-shaped flashing material according to the inven ¬ tion. In the illustrated embodiment the flashing ma¬ terial includes a stress damping and stabilizing layer 1, that may be of a ductile and elastic material based on isobutylene-isoprene rubber of a stretchable and adhesive consistency in the relevant range of temper¬ ature, e.g. from -5°C to 60°C, completely encapsulated between two foil sheetings 2 and 3 that are integral and folded around the layer 1 while being squeezed together along the remaining lateral edges of the flashing plate member. The foil sheetings 2 and 3 may be made from aluminium foil with a thickness in the range from 0.1 to 0.5 mm and are according to the invention provided with flattened folded sections 4 of such a shape that the extreme material layer 4a of each folded section is not in contact with layer 1 in the undeformed ini¬ tial condition of the flashing material, but gets into contact with the stress damping and stabilizing materi¬ al when the folded sections 4 are opened in connec¬ tion with the deformation carried out to make the flashing material fit to the underlying roofing con¬ sisting for instance of conventional undulated tiles. In the illustrated embodiment the folded sec¬ tions 4 are designed as densely adjacent, closed inverted pleats, thereby offering the possibility of stretching the flashing material by almost 100$ in a direction perpendicular to the folded sections and thus an easy adaptation to the roofing by a purely manual deformation processing without the use of tools. There is, however, nothing to prevent spacings between the folded sections. In view of this stretching the stress damping and stabilizing layer has a thickness, preferably in the range from 1 to 6 mm. In the illustrated embodiment it has been made possible to obtain an improved securing to the roofing because the foil sheeting 3, which upon mounting the flashing material is being directed towards the roof- ing, has apertures or perforations 5 in the outwards facing layers 4a of the inverted pleats 4 so that the pressure adhesive layer 1 when the inverted pleats 4 are opened by deformation is partially urged through said apertures 5 to get into adhering contact with the roofing. A second possibility of such an adhesion to the roofing consists in that part of the actual side of the flashing plate member may be free of foil coating and for instance when delivered be covered by a removable protective paper. The illustrated embodiment, however, presents the advantage that it entails a better protection of the pressure adhesive layer 1 against deteriorating climatic changes, thereby making less heavy demands on the stability of the adhesive substance against such influences. The flashing material may be manufactured in that the adhesive layer 1 is wound or rolled on one half of a foil blank cut in a rectangular form and which beforehand is provided with densely positioned folded sections 4, following which the foil blank is folded along a folding line 6 perpendicular to the folded sections and the folded foil sheetings are squeezed together or - adhered on the three remaining lateral edges. The use of aluminum foil makes it possible to produce flashing materials with an effectice surface protection against climatic influences and in various desired colours. As an alternative for use in connection with copper roofs covering a thin copper foil may be used. The design of the folded sections 4 as invert¬ ed pleats entails an optimum combination of stretchabi- lity and ductility by purely manual processing but the folded sections may as a second possibility have a flattened Z-shaped form of the same type which was per se known in connection with leaded flashings prior to the above referenced Danish Patent Application No. 5059/89.

Claims: P A T E N T C L A I M S 1. A leadfree plate-shaped roof flashing materi¬ al having a sandwich structure including a preferably metallic foil and a stress damping and stabilizing layer of ductile material, characterized in that the stress damping and stabilizing layer (1) is completely covered on one side and at least partly covered on the other side by a foil sheeting (2, 3) formed with flat¬ tened folded sections (4) of such a shape that the extreme layer (4a) of each folded section gets into contact with the stress damping and stabilizing layer (1) only when the folded sections open in connection with deforming the flashing material to make it fit to a roofing. 2. A roof flashing material according to claim 1, characterized in that the stress damping and stabi¬ lizing layer (1) is made from a material of a stretch¬ able adhesive consistency in the relevant temperature range. 3. A roof flashing material according to claim 2, characterized in that the stress damping and stabil¬ izing layer (1) is made from a ductile and elastic material based on isobutylene-isoprene rubber and has a thickness in the range of 1 to 6 mm. 4. A roof flashing material according to claims 1, 2 or 3, characterized in that the foil sheetings (2, 3) are folded substantially as inverted pleats. 5. A roof flashing material according to claim 4, characterized in that the inverted pleats (4) are densely adjacent to each other. 6. A roof flashing material according to any of the preceding claims, characterized in that the foil sheetings (2, 3) are of aluminium foil with a thickness in the range of 0.1 to 0.5 mm. 7. A roof flashing material according to claim 4, characterized in that the stress damping and stabil- izing layer (1) is entirely encapsulated between two foil sheetings (2, 3) one (3) of which has apertures or perforations (5) in the outwards facing parts (4a) of the inverted pleats. 8. A roof flashing material according to claim 6, characterized in that the foil sheetings (2, 3) are continuous and folded along a folding line (6) per¬ pendicular to the folded sections (4) about the stress damping and stabilizing layer (1) while the sheetings (2, 3) of the folded foil web are squeezed together along the remaining lateral edges.

Inventors: LARSEN NIELS ADELHOLM, LARSEN, NIELS, ADELHOLM
Applicants: RASMUSSEN KANN IND AS, V. KANN RASMUSSEN INDUSTRI A/S
Application year: 1992
Main classification: E04D13
IPC codes: E04B1, E04D3, E04D5, E04D13