ROOFING-MATERIAL

Abstract: The invention relates to a roofing-material provided with perforations and comprising a bituminized carrier with a non-sticking lower surface and destined for being applied on a substratum and for being covered by an upper layer, which may contain a carrier which is bituminized with modified bitumen, and which may be applied by means of a torch. According to the invention the carrier of the roofing-­ material is bituminized with modified bitumen, and the perforations are so large that the upper layer cay be directly applied on the roofing-material by means of a torch and can be adhered to the substratum via the perforations.

Description: The invention relates to a process according to the preamble of claim 1 and to a roofing material according to the preamble of claim 2. In this process, which is known from practice an under-layer is laid on a substratum consisting for instance of a covered plastic foam, such as polystyrene foam or polyurethane foam, or of an old existing roofing. This under-layer consists of the roofing-material of the type described hereinabove and is composed of glass fibre mat, which is bituminized with blown bitumen and which has a non-sticking surface on one side and is provided with small perforations with a diameter of about 1,5 cm, which together take up about 4% of the total surface. The under-layer is fixed to the substratum at the location of the roof-edges over a width of about 2 metres with an adhesive layer of blown bitumen, which has first been liquefied in a bitumen-heater and which is applied in a sine-shape generally by means of a can.The roofing-material which forms the under-layer is not fixed to the remaining part of the substratum. Subsequently an extra coat of blown bitumen is applied on the roofing-material forming this under-layer, which bitumen has also been liquefied beforehand in a bitumen-heater, whereby the liquid bitumen locally adheres to the substratum through the perforations in the under-layer. Thereupon an upper layer, for example consisting of bituminized Polyester mat, wherein the bitumen is modified with atactic polypropylene, is applied by means of a propane torch or burner or the like on the whole surface of the under-layer with staggered cross-overlappings, whereafter the overlappings are checked and are after-treated, if necessary. The coating of modified bitumen at the lower side of this mat may be thicker than the coating of modified bitumen on the upper side of the mat. This known process and the roofing obtained therewith have been very satisfactory, but nevertheless still have several disadvantages. Although the upper layer is applied by means of the torching-method, so that for this purpose the use of the bitumen-heater,which is in fact very objectionable, is not necessary, this bitumen-heater is yet required with the known roofing for applying the above-mentioned adhesive layer for fixing the under-layer at the location of the roof-edges, as well as for the application of the extra coat, so that the advantage of the use of the torching-method for applying the upper layer is lost again for the greater part. Further the adherence through the perforations in the under-layer amounts only to about 4%, so that the above-mentioned additional fixation of the under-layer along the roof-edges is necessary. Furthermore the roofer has, especially in summer, a lot of hindrance of the extra coat, which remains sticky during a long time, so that walking on it is rather difficult. An important disadvantage connected with the known roofing-material consists in that the extra coat, which has to be applied in liquid condition cannot consist of modified bitumen, as this would make too high demands upon the bitumen-heater. Therefore this extra coat consists of a blown bitumen, while the roofing-material forming the perforated under-layer is made with the application of blown bitumen as well. Since modified bitumen has much better characteristics than blown bitumen, it is of course unfavourable for the quality of the complete roofing when the same can only be partially made of modified bitumen. It is an object of the present invention to further develop the process as described hereinbefore to such extent that the objections mentioned above will be removed in an efficient manner and that it will be possible to use modified bitumen for the complete roofing. For this purpose the process according to the invention is characterized by the steps as defined in the characterising clause of Claim 1. According to the invention the upper layer can be applied by means of a torch and can yet locally be adhered to the substratum via the perforations without the application of an extra coat. With the roofing-material according to the invention it is no longer necessary to fix this material on the substratum at the location of the roof-edges, as the adherence between the upper layer and the substratum via the larger perforations is sufficiently strong. Because the perforations in the under-layer formed from the roofing-material according to the invention are filled with modified bitumen, it will be remunerative to also use modified bitumen when manufacturing this roofing-material. In this way it is achieved that exclusively modified bitumen is used for the complete roofing. As both the adhesive layer of blown bitumen between the under-layer and the substratum at the location of the roof-edges and the extra coat of blown bitumen have become superfluous, it is no longer necessary to use a bitumen-heater, and the whole roofing can be applied by means of the torching-method. A roofing material to be used in the above described process and having the structure as defined in the preamble of claim 2 is characterised by the measures as defined in the characterising clause of claim 2. A preferred embodiment is described in claim 3 and has the advantage that a large quantity of melted bitumen is obtained during the application of the torch, so that a good adherence with the upper layer, as well as, via the perforations, with the substratum, is accomplished, whilst further a buffer is formed against the heat of the propane torch. In this manner it is prevented that the parts between the perforations of the roofing-material, which form the under-layer, would be heated to such an extent that an unintended adherence to the substratum would take place. With this measure, in combination with the application of the non-sticking surface at the lower side of the under-layer formed from the roofing-material according to the invention, an adherence to the substratum outside of the perforations is avoided, so that no formation of blisters between the under-layer and the substratum can occur. Further preferred embodiments are described in claims 4-6 It is observed that GB-A-1083845 discloses a roofing material comprising a sheet of absorbant material impregnated with bituminous material and provided with small perforations; the lower surface of this sheet is provided with a layer of bituminous material to which a granular material is applied. After the application of such a sheet on the roof it is covered by bitumen, coaltar or asphalt which passes through the apertures. The invention will be elucidated hereafter with reference to the drawing. Fig. 1 is a partial top view of several adjacent strips of the roofing-material according to the invention. Fig. 2 is a section along the plane II-II in fig. 1 on a larger scale. The drawing shows a number of strips 1 formed from the roofing-material according to the invention, which are used as the under-layer of a roofing. These strips 1 may be delivered in the form of rolls and are applied on a substratum 2,which for instance consists of covered plastic foam like polystyrene foam, polyurethane foam or the like, or of an old roofing. The strips 1 each consist of a carrier 3 bituminized with modified bitumen 4, and provided at the lower side with a coat of fine gravel 5 applied during the manufacture of the strips. As an alternative for the gravel 5 another type of non-sticking material, such as a plastic foil may be used. The strips 1 of roofing-material according to the invention,which form the under-layer,are provided with perforations 6, having a diameter of 50-110 mm and preferably of about 70 mm, while the degree of perforation is 8-14% and preferably about 11%. With advantage the strips 1 may comprise a bituminized perforated glass fibre mat,wherein the bitumen is modified with an atactic polypropylene or a styrene-butadiene-styrene co-polymer. With the strips 1 of the roofing-material according to the invention the coating of modified bitumen 4' lying above the carrier 3 is thicker than the coating of modified bitumen 4'' lying underneath the carrier. At one longitudinal side each strip 1 of the roofing-material according to the invention has a thinned selvage 7 without gravel. For constructing the complete roofing first a number of strips 1 are laid on a substratum 2 which strips are formed from the roofing-material according to the invention and are serving as an under-layer. As appears from figs. 1 and 2, the selvage 7 always overlaps the adjacent strip 1. Hereafter the strips of the upper layer (not shown) each consisting of a carrier bituminized with modified bitumen, for instance of bituminized polyester mat, wherein the bitumen is modified with e.g. an atactic polypropylene, are applied by means of the torch on the roofing-material according to the invention which forms the under-layer.The coating of modified bitumen underneath the mat is thicker than the coating of modified bitumen above the mat. The strips of the upper layer locally adhere to the substratum via the perforations 6 in the roofing-material which forms the under-layer. The roofing-material according to the invention has important advantages. In the first place the adherence to the substratum is at least three times as strong as with the known roofing-material, so that no additional adherence along the roof-edges is necessary anymore. Further, due to the larger dimensions of the perforations in the roofing-material according to the invention the upper layer can be adhered to the substratum by means of the torching-method, so that the use of a bitumen-heater is no longer necessary and the application of the complete roofing can be realized very quickly. Since the extra coat between the under-layer and the upper layer has become superfluous, the roofing may be applied without any objection even if the weather is very warm. A further important advantage obtained according to the invention consists in that for the construction of the roofing only modified bitumen and no blown bitumen is used.

Claims: A process for covering a roof comprising the steps of covering a substratum on said roof with roofing material consisting of a bitumized carrier having a non-sticking lower surface and being provided with perforations, followed by the step of applying to this roofing material an upper layer consisting of a carrier which is bituminized with modified bitumen, characterized in that in said first step a roofing material is used comprising a carrier which is bituminized with modified bitumen, the perforations in said carrier being so large that in the second step by using a torch the upper layer is made to adhere to the substratum via the perforations. Roofing-material provided with perforations (6) and comprising a bituminized carrier (3) with a non-sticking lower surface (5) and destined for being applied on a sustratum (2) and for being covered by an upper layer (4), which may contain a carrier which is bituminized with modified bitumen, and which may be applied by means of a torch, characterized in that the carrier (3) of the roofing-material is bituminized with modified bitumen, and the perforations (6)have a smallest inner dimension of 50-110 mm, and preferably of about 70 mm.Such that the upper layer (4) can be directly applied on the roofing-material by means of a torch and can be adhered to the substratum (2) via the perforations. Roofing-material according to claim 2, characterized in that the coating (41) of modified bitumen lying above its carrier (3) is thicker than the coating (4'') of modified bitumen lying underneath its carrier (3). Roofing-material according to claim 3, characterized in that the degree of perforation is 8-14% and preferably about 11%. Roofing-material according to any of the claims 2-4, characterized in that the same comprises bituminized perforated glass fibre mat, wherein the bitumen is modified with atactic polypropylene or styrene-butadiene-styrene co-polymer. Roofing-material according to any of the claims 2-5, characterized in that the same has the form of a strip, which has a thinned selvage at one longitudinal side.

Inventors: SMITS, PHILIPPUS ROBERTUS JACOBUS
Applicants: CBL CONSOLIDATED LTD BASEL
Application year: 1984
Main classification: E04D5
IPC codes: E04D5, D06N5, B32B11