Abstract: The invention relates to a method for leak detection in roofs and interior and exterior floors covered or clad with sealing layer products and an apparatus for carrying out the method. Smoke gas is fed into and made to spread in a space between the sealing layer and the support on which the sealing layer rests. Any of the smoke gas penetrating in an outward direction through holes in the sealing layer is detected when it escapes from the holes on the outer side of the roof cover, whereby their locations can be determined. The apparatus for carrying out the method according to the invention comprises a device for generation of smoke gas, transport elements to move the smoke gas to the space where the smoke gas is made to spread, and a generator that creates an air flow for transport of the smoke gas.

Abstract: A non-woven fabric for use as a bitumen coated and possibly bitumen impregnated carcass in a water-proofing membrane, particularly for roofs, is distinguished in that a proportion of at least 75% by weight of the fabric fibers comprise organic synthetic fibers, preferably polyester fibers, and cellulose fibers, preferably wood pulp fibers, the organic synthetic fibers constituting at least 10 and at most 90% by weight of this fiber proportion. The non-woven fabric is coated with a binder compatible with bitumen in an amount of at least 10%, preferably at least 20% of the fabric weight, the binder being selected so as to be thermally stable up to a temperature of at least 160.degree. C. and for limiting the water transport ability of at least the cellulose fibers. The invention also includes water-proofing membranes including a carcass formed by such fabric, which is coated and possibly impregnated with bitumen.