A brick is building material used to make walls, pavements and other elements in masonry construction. Traditionally, the term brick referred to a unit composed of clay, but it is now used to denote any rectangular units laid in mortar. A brick can be composed of clay-bearing soil, sand, and lime, or concrete materials.
Concrete is used to create hard surfaces that contribute to surface runoff, which can cause heavy soil erosion, water pollution, and flooding, but conversely can be used to divert, dam, and control flooding. Concrete is a contributor to the urban heat island effect, though less so than asphalt.
Timber cladding is an increasingly popular choice for finishing the outside of commercial and domestic properties. Otherwise known as timber weatherboarding or timber siding, it is an attractive and economical way to finish the exterior of both old and new buildings.