Abstract: A universal air-vapor barrier box for electrical outlet boxes is convertible between a fixed mode and a foldable mode. The barrier box is manufactured in the fixed mode with top, bottom, side, and back walls and top, bottom, and side flanges. The back wall has a groove that extends between the top and bottom walls. Grooves in the top and bottom walls are aligned with and continuous with similar grooves in the top and bottom flanges. In the fixed mode all the walls and flanges are unitary members. The barrier box receives an electrical outlet box, and the two are nailed together to a building stud or rafter. With many electrical outlet boxes, there is sufficient room within the barrier box when it is in the fixed mode to swing a hammer and drive the nails. With large electrical outlet boxes, the grooves in the top and bottom walls and flanges are cut through to place the barrier box in the foldable mode.

Abstract: A five-sided air-vapor barrier box seals an electrical outlet box in a building wall. The barrier box has an open side, around which outwardly extend reinforced flanges perpendicular to the associated barrier box walls. The back surface of a flange is placed against the face of a wall stud, and a barrier box side wall is placed against the side of the stud. The electrical outlet box and barrier box are nailed together to the stud through the barrier box side wall. A thin sheet of moisture impervious material is placed over the wall studs and barrier box. An opening in the film is cut approximately coextensive with the barrier box open side. A bead of caulk is deposited on the flanges, and the film is pressed against the flanges, thereby creating an air and moisture seal. The barrier box and film are then covered with the finish wall covering. The barrier box walls are made of two thicknesses. The wall portions adjacent the flanges are of a relatively great thickness to provide rigidity to the barrier box.