An exterior wall brace used to resist lateral forces where roof beams rest on the wall is called what?

• A. Column
• B. Pilaster
• C. Buttress
• D. Pier

Answer: (C)

An exterior wall brace that resists lateral forces from roof loads is a buttress. A buttress projects from the wall and works by transferring the outward thrust from the roof or arches into the ground, preventing the wall from bowing outward. This is different from a column, which is a vertical member that carries weight downward; a pilaster, though attached to a wall, is usually shallow and primarily decorative or lightly reinforcing rather than designed to counter horizontal thrust; and a pier is a substantial vertical support that carries heavy loads, often supporting arches or vaults, not a wall brace that resists lateral push. The buttress specifically addresses the outward forces the roof and arches impose on the wall, keeping the structure stable.