Furring strips are thin, narrow strips of wood or metal that are applied to a structure to level or raise the surface, to prevent dampness, to make space for insulation, to level and resurface ceilings or walls, or to increase the beam of a wooden ship. They are typically 1 inch x 2 inches or 1 inch x 3 inches in size. Furring strips 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, with wider spacing typically used behind heavy boards that support ceramic tiles and closely spaced strips needed for thin paneling or plaster. Furring strips can be utilized for a variety of interior as well as exterior construction projects, such as creating a level, solid frame or a supportive structure, allowing for easy and effective attachment of wood, paneling, or plaster to a wall or a ceiling. They can also be used to create air space between the plaster and the wall itself, which is useful when installing insulation into the walls. Metal furring strips are used for commercial projects or in towns where fire-proof supporting elements are required by the local building code.