Which construction type is described as Heavy Timber (Barn)?

• A. Type I
• B. Type II
• C. Type III
• D. Type IV

Answer: (D)

Heavy Timber construction uses very large wood members—thick columns and beams that are solid or laminated—as the main structural frame, with exterior walls typically noncombustible. This style is often associated with barns and other large open interiors, which is why it’s commonly called Heavy Timber or barn construction. The mass of the timber allows the structure to maintain its integrity for longer in a fire because the wood chars slowly, forming a protective veneer and delaying collapse. Among the standard construction types, this description matches the Type IV category, distinguishing it from the fire-resistive Type I, the noncombustible Type II, and the ordinary wood-frame Type III.