NOVELTY - A photo-voltaic building material comprises a planar flexible substrate, photo-voltaic device fixed to substrate, an encapsulant material on light incident side of photo-voltaic device, and contact adhesive covering reverse side of substrate. The device generates an electric current on absorption of light. The encapsulant material which covers the photo-voltaic device is light-transmissive.    USE - As electrical power-generating building material, especially as roofing material (claimed), and for sheathing walls, canopies and other portions of building structures, and as photo-voltaic power generating module (claimed), for automobiles, watercraft and aircraft.    ADVANTAGE - A building material capable of generating electrical power, and which is flexible, low cost, light-weight and self-adhesive is offered. The material can be readily rolled up for transport and storage, and can be readily and fixedly installed on to a variety of building structures. The building material can be fabricated in a variety of configurations, and owing to its high adhesion to different substrates, can be used in various applications. The material has low flammability, and can also be configured to include fire-break structures, which limit flame-spread. Through the use of the building material, combined with embossing and patterning techniques it has been found that advantages of large area photo-voltaic structures can be combined with the aesthetic appeal of conventional small geometry roof shingles. Fabrication of customized photo-voltaic modules and devices that eliminate problems associated with material handling and control, and thereby permits low cost manufacture of different device configurations and types is enabled.    DETAILED DESCRIPTION - A photo-voltaic building material (10) comprises a planar flexible substrate (12), a photo-voltaic device (14b) fixed to substrate, an encapsulant material (32) disposed so as to cover light incident side of photo-voltaic device, and a contact adhesive layer (40) covering reverse side of substrate. The photo-voltaic device generates an electrical current in response to absorption of light incident on it. The device is fixed on substrate, so that a top, light incident side, faces away from substrate. At least a portion of encapsulant material which covers the photo-voltaic device is light-transmissive.    INDEPENDENT CLAIMS are also included for;    (1) Photo-voltaic power generating module, comprising the photo-voltaic building material and a support;    (2) Photo-voltaic roofing material, comprising photo-voltaic devices electrically interconnected and supported on substrate, spaced apart from each other. A pair of electrical terminals supported on substrate are provided to connect to the photo-voltaic devices; and    (3) A method of fabricating a photo-voltaic power generating module, by adhesively affixing the photo-voltaic building material comprising substrate, photo-voltaic device and adhesive on a support.    DESCRIPTION OF DRAWING(S) - The figure shows cross-sectional view of photo-voltaic building material.    Photo-voltaic building material (10)    Substrate (12)    Photo-voltaic device (14b)    Bus bars (16b,18b)    Encapsulant material (32)    First encapsulant material layer (34)    Top layer of encapsulant material (36)    Contact adhesive (40)    Release layer (42)