JP2902323B

PURPOSE: To form a waterproof layer having dew condensation preventing effect with an earth retaining wall on the outside of the outer wall of an underground building. CONSTITUTION: A plurality of water impermeable foamed sheets 2 are partially fixed to the whole surface of an earth retaining wall 1 formed on a vertical wall surface recessed in the ground G to form a foamed sheet laid surface, and a plurality of porous base sheets 4 are partially fixed to the whole surface of the foamed sheet laid surface to form a porous base sheet laid surface. A gently coagulating rubber asphalt emulsion is sprayed to the whole surface of this laid surface to form a rubber asphalt waterproof layer 6 having the emulsion impregnated and coagulated in the porous base sheet. An underground outer wall 7 for building is constructed on the whole surface of the waterproof layer 6 through or without a resin mortar 8.