California IDEX Practice Exam

A project featuring heavy timber construction falls under Type IV building classification. This construction type is specifically designed to utilize large wood members that provide significant structural integrity while also offering a level of fire resistance due to the mass of the timber. Heavy timber elements are naturally fire-resistant to some extent because they char on the outside when exposed to flames, which can help protect the inner layer of the wood. Type I construction consists of non-combustible materials, Type II can also use non-combustible materials but is less stringent, while Type V incorporates wood framing that might not meet the criteria for heavy timber. Thus, the recognition of heavy timber as a distinct and specialized construction method that supports both structural stability and fire resistance solidly establishes it within the Type IV category.