Abstract: A photovoltaic building assembly (2) includes a building support surface, typically a roof (4) or a wall (6), on which a PV module support assembly (12) is mounted. The support assembly includes a base (18) secured to the support surface, and an upper portion (14, 16; 14a, 31, 33). A PV module (10) is mounted to and is supported by the body (14, 14a) of the upper portion. A foam insulation layer (22) is sprayed onto the support surface to embed the base and lower ends of the legs therein. A weather-resistant layer (24) is applied to the outer surface of the insulation layer to prevent moisture from reaching the building surface. The base can be secured to the building support surface by an adhesive (32) or by mechanical fasteners (34) as well as by simply embedding the base within the insulation layer. The assembly provides for electricity generation, building thermal insulation and building waterproofing in a lightweight construction assembly.