A photovoltaic building material comprises a substrate having one or more photovoltaic generating devices encapsulated thereupon. The substrate includes a body of contact adhesive material, preferably protected by a release layer. The material is readily installed onto a roof, wall or other portion of a building structure by use of the adhesive. The material can also be used for the custom fabrication of power generating modules, and such modules and methods for their manufacture are disclosed herein.