Process for making a built-up thermal insulating and bituminous waterproofing assembly

A process for making a built-up bituminous waterproofing and thermal insulation assembly, comprising the steps of:

• (a) placing onto the surface of a substrate a plurality of prefabricated, thermal insulating and bituminous waterproofing boards, each consisting essentially of (i) a thermal insulating layer having an upper surface and a lower surface, said thermal insulating layer being made of thermal insulating material;
• (ii) a first, flat, fibrous sheet having an upper surface and a lower surface, the lower surface of said first sheet being bonded to the upper surface of said thermal insulating layer in direct, face-to-face, mutually adhering contact;
• (iii) a modified bitumen layer having a thickness within the range of from 2 to 25 mm and having an upper surface and a lower surface, said modified bitumen layer consisting essentially of a uniform mixture of waterproofing bitumen and 50% to 90% by weight, based on the total weight of the mixture, of pieces of at least one inorganic filler, the lower surface of said modified bitumen layer being bonded to the upper surface of said first sheet in direct, face-to-face, mutually adhering contact;
• and (iv) a second, flat, fibrous sheet having an upper surface and a lower surface, the lower surface of said second sheet being bonded to the upper surface of said modified bitumen layer in direct, face-to-face, mutually adhering contact, said boards being placed onto the substrate surface adjacent to one another with the edges of said boards being slightly spaced to provide clearances therebetween, said boards forming a layer on said substrate surface with the thermal insulating layer of each of said boards being in close adhering contact with said substrate surface;
• (b) then sealing the clearances between said boards with sealing material;
• and
• (c) then forming a continuous, waterproofing layer over the entire upper surface of said boards and said sealing material, said waterproofing layer being integral therewith.