Abstract: A method of cladding a building wall surface with individual prefabricated panels and trim mouldings with any fasteners and joints between the panels and trim being covered on site with a coating of stucco to produce a flush finished stucco surface. Each panel has a uniform transverse cross-sectional profile, and a core of foam material coated with a weatherproof stucco coating on its exterior surface. Tongue and groove joints are disposed along the longitudinal surfaces and a longitudinal recess in the exterior surface adjacent each tongue and groove joint is adapted to receive a layer of joint coating to fill the recess and cover the longitudinal joints flush with the external surface. The wall surface is installed by cutting the elongate cladding panels to the approximate length of the wall and mounting the cladding panels temporarily to the wall substrate, such as plywood for example.