and 26 be overlapped by a suitable amount which is approximately 11 4 inches as will be understood if the angle face 32 is raised to an elevation approximately equal to the thickness of the plank this is a height of something around 1 4 to 1 2 inch the angle face 32 is constructed with a slight angle in the manner illustrated the shaped sectional profile is formed by extrusion the extruder mold is relatively simpler to construct with an open space behind the angle face 32 and between the faces 30 and 34 in actuality this construction is relatively stiff notwithstanding the open side as illustrated being relatively stiff it can be subjected to the typical construction site bending and abuse which inevitably occurs nevertheless it is a quality device which can be built in the manner described and installed in a routine fashion if bent or dimpled it will still maintain dimensional stability and is restored from the plastic memory to the shape illulstrated consider now the installation of the strip 20 before placing any of the planks on the framing the normal construction procedure involves attachment of a vapor barrier such as felt or tar paper on the exterior of the framed structure insulation material may by placed between the wall studs to support an outside vapor barrier all of that is placed in the framed building before fastening the strip 20 on the structure the strip 20 is nailed with just a few nails it can be conveniently nailed to.