Which type of construction is heavy timber?

Heavy timber construction falls under Type IV construction, which is characterized by large wooden structural members. This method utilizes solid timber that is at least 8 inches in dimension and is known for its fire-resistive properties due to the thickness of the timber, which allows it to withstand fire for a longer duration before failing. The heavy timber elements contribute to the overall strength and stability of the structure, making it a preferred choice for certain types of buildings, such as warehouses and agricultural facilities.

Types II and III, often referred to as non-combustible and ordinary construction respectively, typically utilize lighter weight materials that may not provide the same level of fire resistance as heavy timber. Type V construction is characterized by wood-frame structures that are more lightweight and commonly used for residential buildings. Thus, the defining traits of heavy timber that align with Type IV make it the correct answer for this question.