Most siding consists of pieces of weather-resistant material that are smaller than the wall they cover, to allow for expansion and contraction of the materials due to moisture and temperature changes. There are various styles of joining the pieces, from board and batton, where the butt joints between panels is covered with a thin strip (usually 1 to 2 inches wide) of wood, to a variety of clapboard, also called lap siding, in which planks are laid horizontally across the wall starting from the bottom, and building up, the board below overlapped by the board above it. These techniques of joinery are designed to prevent water from entering the walls. Siding that does not consist of pieces joined together would include stucco, which is widely used in the Southwest. It is a plaster-like siding and is applied over a lattice, just like plaster. However, because of the lack of joints, it eventually cracks and is susceptible to water damage. "Rainscreen" construction is used to improve siding's ability to keep walls dry.