Single ply roofing base sheet adherence method

Claim 3

The method of claim 1 wherein said perforations are about 40 mm to about 100 mm in diameter.

Claim 4

The method of claim 2 wherein said bitumen/polymer mixture has a standard ASTM ring and ball softening point of about 105° C. to about 155° C.

Claim 5

The method of claim 2 wherein said reinforcing fibrous material of said underlayment is non-woven polyester.

Claim 6

The method of claim 2 wherein said overlayment membrane is about 4 mm to about 7 mm thick, weighs about 4.3 kg to about 5.4 kg per square meter, and has a layer of bitumen/polymer mixture on its underside at least 2 mm thick.

Claim 7

The method of claim 2 wherein said underlayment is no thicker than about 2.5 mm.

Claim 8

In the method of installing a waterproofing membrane over a relatively flat substrate wherein a single ply overlayment waterproofing membrane having an underside consisting essentially of a bitumen/polymer mixture at least 2 mm in thickness and having a ring and ball softening point between about 105° to about 150° C. is placed over a relatively thin single ply underlayment membrane which has been suitably adhered to the surface to be waterproofed, said underlayment membrane being further characterized in that it is no thicker than about 2.5 mm and consists of a non-woven fibrous mat substantially saturated with essentially the same bitumen/polymer mixture as said overlayment membrane, and heating the underside of said overlayment membrane as it is being placed over the underlayment membrane such that the bitumen/polymer mixture in the waterproofing membrane reaches a point sufficiently above its flow temperature that the overlayment and underlayment membranes fuse together to form essentially a single layer membrane, the improvement wherein said underlayment membrane is further characterized by perforations relatively uniformly dispersed across its surface area, ranging in size from about 10 mm to about 150 mm, and constituting no more than about 15 to about 25% of the total surface area of the underlayment, whereby during the placing of the overlayment membrane onto the perforated underlayment, the heated bitumen/polymer mixture flows through said perforations to the substrate to a sufficient degree so as to adequately maintain the final waterproofing membrane on the substrate under existing environmental conditions without the need for additional adhesive or treating steps.

Claim 9

In the method of installing a waterproofing membrane over a relatively flat substrate wherein a single ply overlayment waterproofing membrane having an underside consisting essentially of a bitumen/polymer mixture at least 2 mm in thickness and having a ring and ball softening point between about 105° to about 150° C. is placed over a relatively thin single ply underlayment membrane which has been suitably adhered to the surface to be waterproofed, said underlayment membrane being further characterized in that it is no thicker than about 2.5 mm and consists of a non-woven fibrous mat substantially saturated with essentially the same bitumen/polymer mixture as said overlayment membrane, and heating the underside of said overlayment membrane as it is being placed over the underlayment membrane such that the bitumen/polymer mixture in the waterproofing membrane reaches a point sufficiently above its flow temperature that the overlayment and underlayment membranes fuse together to form essentially a single layer membrane, the improvement wherein said underlayment membrane is further characterized by perforations relatively uniformly dispersed across its surface area, ranging in size from about 10 mm to about 150 mm, and constituting no more than about 15 to about 25% of the total surface area of the underlayment, whereby during the placing of the overlayment membrane onto the perforated underlayment, the heated bitumen/polymer mixture flows through said perforations to the substrate to a sufficient degree so as to adequately maintain the final waterproofing membrane on the substrate under existing environmental conditions without the need for additional adhesive or treating steps.