long thin strips of wood used to make backing surfaces to support the finished surfaces in a room. They typically measure 1" x 2" or 1" x 3". They can be laid out perpendicular to studs or joists and nailed to them, or set vertically against an existing wall surface. The spacing between the strips depends on the type of finishing material. Wider spacing is typically used behind the heavy boards that support ceramic tiles. Closely spaced strips are needed for thin paneling or plaster.