truss assembly 22 and studs 18 so it also surrounds the basement 26 as it extends to the opposite wall persons versed in the art will appreciate that vapor barrier 45 is not commercially available in a sufficient size as a practical matter to completely enclose a house or other building in a single sheet the vapor barrier 45 is therefore obtained in the largest roll commercially available and during construction of the building 10 it is unrolled preferrably in a vertical direction and positioned as shown in fig1 with any edges overlapped by other sections of vapor barrier 45 which preferrably are sealed by means of a suitable glue or caulking compound so that when the building 10 is constructed vapor barrier 45 is substantially a continuous vapor barrier which completely surrounds the living areas 13 and 17 and the basement 26 except for the usual doors and windows and these openings are also sealed as tightly as possible in the usual manner as shown in fig1 in the preferred embodiment a thin plywood sheet 47 is secured to the exterior side of the vapor barrier 45 by nailing sheet 47 through the vapor barrier 45 into studs 28 so that the interior surface of the vapor barrier 45 faces insulation 29 in the preferred embodiment an array of truss shoes 48.