The waterproof covering will consist of a self-thermoadhesive distilled bitumen polymer waterproofing membrane in bands, 4 mm thick, with CE marking in accordance with UNI EN 14695 for laying under poured asphalt, type AUTOTENE ASFALTICO STRIP EP POLIESTERE, which adheres for 40% of the surface and distributes the damp of the support to avoid the formation of steam bubbles. By previously using the AUTOTENE ASFALTICO EP POLIESTERE membrane with the lower face completely thermoadhesive, the area around the discharge holes will be coated with a piece of membrane at least 20 cm broader than the joining bed of the drainpipe; after having removed the silicone-coated film, this will be heat-bonded on the laying surface. With the same technique a 20 cm wide band of the same membrane will be bonded across the corner between the flat part and the vertical parts. Then the AUTOTENE ASFALTICO STRIP EP POLIESTERE coating of the flat part will be torch-bonded on this. The coating of the flat surface with AUTOTENE ASFALTICO STRIP EP POLIESTERE will take place by unwinding the first roll starting from the lowest part of the pitch and removing the silicone-coated film from below the fabric. The next roll, without removing the silicone-coated film, is unwound and aligned to the side of the membrane laid previously, overlapping on it laterally for about 6 cm. The silicone-coated film is subsequently removed from below the roll, making sure you press it down with your feet. The end joint is subsequently torch-bonded after removing the silicone-coated strip of the lateral overlap. Pre-welding of the lateral overlap can then be carried out, which will be obtained by pressing the overlap after having removed the silicone-coated strip which covers it. The definitive bond, together with sticking to the laying surface, will be done with the heat from laying the melted asphalt floor. The coating of the vertical parts will consist of a strip of AUTOTENE ASFALTICO EP POLIESTERE membrane which will be heat-bonded and will drop by at least 20 cm onto the membrane that covers the horizontal surface, and vertically by about 20 cm over the height of the floor. The vertical turn-up will be protected by reinforced plaster with a metal mesh laid prior to laying the next waterproofing layer and melted asphalt floor 25 mm thick.