Abstract: A thin, relatively flexible sheet formed in strips for application upon a roof surface and the like, with successive strips in overlapping relationship, is formed of a lamination of a lower layer made of a low temperature heat softenable material such as asphalt, a thinner middle layer formed of a non-woven fabric of relatively stable fibers, and an upper layer formed of a high temperature melting point monolithic material such as an ethylene vinyl acetate copolymer. Heat is applied, as for example, by a hand operated flame torch, to the lower layer of a strip to soften it. Then the strip is laid upon the surface, with an edge portion overlapping the next adjacent strip previously laid upon the surface so that each strip adheres to the upper layer of the preceding strip upon cooling and solidification of the heat softened asphalt layer.