Abstract: Composite panels, each having a rigid board facing, made from gypsum, concrete, wood, or fibrous material, backed by a layer of foamed plastic insulating material whose reverse face is protected by a highly reflective, flame-retardant, moisture-vapor-proof material applied thereto, are held together edge-face to edge-face in building construction by special retaining clips which secure the panels to supporting structure, such as exterior, load-bearing walls, roof, or ceiling, and also serve to guide installation of the panels so that flush registry is assured without time consuming care in installing an additional panel relative to one already in place. The clip has flanges extending perpendicularly from lateral edges of a web strip whose width depends upon the use intended and the panel thickness. A flange along one edge of the web strip is adapted to be secured directly to the supporting structure.

Abstract: A composite panel-board is made up of a rigid, gypsum board, base panel having a rigid, organic plastic, foam layer formed in-situ on, self-adherent to, and essentially covering one of the broad, flat surfaces of the gypsum board base panel. A water-vapor-resistant, flame-retardant layer is adherent to and covers the otherwise exposed, broad surface of the rigid foam layer. The composite panel-board is fabricated by attaching upwardly extending edge sheets on or adjacent to the mutually opposite, side edges of the gypsum board panel so that the mutually opposite edge sheets, together with the gypsum board panel, form a trough. The upper surface of the gypsum board panel is heated to a temperature of at least about 95.degree. F in the presence of a water unsaturated atmosphere, and then a uniform layer of a foamable, liquid, organic plastic material is applied to the upper surface of the gypsum board panel.