SHEET OF ROOFCOVERING MATERIAL

Abstract: Sheet consisting of a porous base layer (1) provided with apertures (2) distributed over its surface, over which base layer is bituminous covering layer has been applied under insertion of a perforated plastic film (4) so that the covering layer (6) is adhered to the base layer through the perforations (5) of the film, such, that by the exceeding of a certain shear stress between the base layer and the covering layer, the bitu­ minous bond of the base layer with the covering layer on the spots of the perforations is torn loose coupled with a shifting of the base layer and the covering layer with respect to each other.

Description: The invention relates to a roofcovering material, formed by a porous base layer, onto which under the insertion of a separating layer a bituminous covering layer has been applied, and in which the separating layer is provided with perforations, through which the covering layer is adhered to the base layer. Such a roofcovering material is disclosed in the DE-A-2 519 226, and in which the base layer is formed by hard foam blocks, onto which the bituminous covering layer has been applied under the insertion of a separating layer of for instance paper. As the hard foam is impermiable for gas and vapour, the upper, covering layer is through the perforations of the separating layer spot bonded to the hard foam blocks so that moisture trapped between the covering layer and the base layer may escape between the spot bonds to the surroundings. Further, the roofcovering according to the DE-A-2 519 226 will not be adhered with its hard foam base layer to the roof plane but only simply is laid down thereon, while the spotbonding between the covering layer and the base layer is intended to be a permanent one. As distinct from the roofcovering material according to the DE-A-2 519 226, the roofcovering according to the present invention is characterized, in that the base layer is formed of glassfiber, which is permeable for gas and vapour and which is provided with apertures, through which molten bituminous material from the covering layer may pass to adhere the covering to a roof plane, while the separating layer is formed by a plastic film in which the size of the perforations is considerably smaller than the size of the apertures, such, that by the exceeding of a certain shear stress between the base layer and the covering layer, the bituminous bond of the base layer with the covering layer present on the spots of the perforations is torn loose during which the base layer and the covering layer shift with respect to each other. To apply the roofcovering material according to the invention onto a roof plane, the bituminous covering layer partly is molten on the spots of the apertures in the base layer, after which this molten material may get strongly and permanently adhered to the roof plane and in this way the roof covering material is applied onto the roof plane. In a suitable manner the roof covering material may be unrolled from a roll onto the roof plane, while, at the same time, the lower side of the material immediately upstream of the line of contact of the roll with the roof plane is heated by means of one or more burners to melt the bituminous material of the covering layer, during which the plastic film on the spots of the apertures is burned away and the molten bituminous material may pass through the apertures to come into contact with the roofplane to adhere strongly and permanently the covering layer thereto. In doing so, the flame of the burner or the burners may come in touch with the bituminous covering layer only immediately through the apertures in the base layer, to melt there the bituminous material, so that by further unrolling of the roofcovering material over the roof plane, this roofcovering material gets adhered to the roof plane only on the spots of the apertures in the base layer. When the roofcovering material is applied onto a roof plane in which fissures or cracks may be formed, or which the roof plane under the influence of moisture and/or heat may expand the glassfiber film between the apertures will be subjected to stress, and as the glassfiber layer hardly has any elasticity, it will rip up causing the weak and not permanent bituminous bonds through the perforations of the plastic film to be torn loose, so that the glassfiber layer may shift underneath the covering layerr without causing any cracks therein. By the size of the perforation in the plastic film and the number of perforations per unit of surface, the limiting value of the shear stress may be chosen in a very exact way, at which the covering layer will be torn free from the glassfiber layer to become lying loose thereon. In a suitable embodiment of the roofcovering material according to the invention, the base layer is provided on its side turned away from the covering layer, with a heat resistant or fireproof protective layer. The heatresistant- or fireproof protective layer effects, that, when applying and at the same time heating the lower side of the roof covering material, only the material of the bituminous covering layer on the spots of the apertures in the base layer is molten, during which the permeability of the porous base layer for vapour and moisture remains unaffected. This permeability for vapour and moisture is of special importance because, when moisture and vapour should be enclosed or trapped underneath the roofcovering material and then could not escape any more, such may cause the forming of blisters in the applied roofcovering materal. The apertures spaced over the surface of the base layer may have a section with a surface of 1 cm2 to 100 cm2. Preferably a section surface of the apertures is applied of about 6 cm2. In a suitable embodiment of the invented roof covering material the rows of apertures enclose an angle with the logitudinal direction of the sheet or the band, that is to say, with a side edge of the sheet or the band, different from 0 ° and 90 ° , and more in particular has a value between 5° - 15 ° and 75 ° - 85 ° . By this measure it is achieved, that a row of apertures may not to entirely come to lie over a crack in the roof plane generally extending according to the transverse of longitudinal direction of the sheet of roofcovering material. For covering up cracks formed in the roof plane, suitably a sheet or band of roofcovering material may be applied, consisting of a porous base layer, particularly of glass fibers, onto which a bituminous covering layer is applied, and in which the covering layer under insertion of a perforated plastic film is applied over the narrower base layer and extends sideways with two side strips over the base layer. By means of the sidestrips the roofcovering material according to this embodiment then may be adhered to the roof plane. In the accompanying drawing an embodiment of the invention is illustrated by way of example. As is shown in the drawing, the sheet of roof covering material according to this embodiment is formed by a base layer 1, of non-woven glassfibers and which, distributed over its surface, is provided with apertures 2. On its lower side, the base layer is provided with a heat resistant or fire proof protective layer 3. Over the base layer 1, a perforated plastic film 4 has been applied separating the base layer from the bituminous covering layer as applied over the film 4, however such with the exception of the perforations 5 of the film through which the material of the covering layer 6 has come in touch with the base layer 1, and has gotten there adhered to the base layer, and by means of which a limited bond of the bituminous covering layer 6 with the base layer 1 has been effected. This bond may be torn loose across the perforations when a certain shear stress arises between the base layer and the covering layer. The high-elastic covering layer, preferably consisting of 80% bitumen and 20% SBS (styrene-butadiene-styrene) further is provided with a top layer 7 of slate-chippings.

Claims: 1. Roofcovering material, formed by a porous base layer, onto which under insertion of a separating layer a bituminous covering layer has been applied, and in which the separating layer is provided with perforations through which the covering layer is adhered to the base layer, characterized in that the base layer is formed of glassfiber permeable for gases and vapour and being provided with apertures (2), through which molten bituminous material from the covering layer (6) may pass to adhere the covering layer (6) to a roof deck, while the separating layer is formed by a plastic film (4) in which the size of teh perforations (5) is considerably smaller than the size of the apertures (2), such, that by the exceeding of a certain shear stress between the base-layer and the covering layer, the bituminous bond of the base layer with the covering layer present on the spots of the perforations is torn loose during which the base layer and the covering layer shift with respect to each other. 2. Roofcovering material as claimed in claim 1 characterized in that the glass fiber layer (1) at its side turned away from the covering layer (6) is provided with a heat resistant- or fire-proof protective layer (3). 3. Roofcovering material as claimed in claim 2, characterized in that the protective layer (3) is permeable for gas and vapour. 4. Roofcovering material as claimed in one of the preceeding claims, characterized in that the apertures (2) distributed over the glassfiber layer (1) are having a size varying from 1 cm2 to 100 cm2, particularly 6 cm2. 5. Roofcovering material as claimed in one of the preceeding claims, characterized in that the rows of apertures (2) enclose with the length direction of the material an angle differing from 0° and 90° degrees, and particularly is lying between 5°- 15° degrees and 75° - 85° degrees.

Inventors: MUELBECK, MARTIN
Applicants: MODIGLASS MODIFIED ASPHALT- AND GLASSMATMACHINES LTD
Application year: 1987
Main classification: E04D5
IPC codes: E04D5