Abstract: Roofs of buildings and the like are waterproofed by applying thereto a plurality of preformed, sheet-like, flexible waterproofing laminates each comprised of (i) a lower sheet support layer (preferably a plastic film or foil) non-removably adhered to (ii) an intermediate layer of waterproofing, self-adhesive, bituminous composition such as rubberized asphalt which in turn is removably adhered to (iii) an upper layer of protective sheet material (e.g. siliconized paper). The surface of the lower sheet support (i) remote from the bituminous layer (ii) is non-adherent and the laminate is applied to the roof with such non-adherent surface adjacent the roof. The uppermost protective sheet layer (iii) is subsequently removed exposing the self-adhesive bituminous layer to which is thereafter applied a weathering layer (e.g. a coating of gravel). The non-adherent surface nature of the lower sheet support layer allows any moisture entrapped below the applied waterproofing laminate to move and be distributed or vented.