Which construction type is often prone to fire spread due to wood being the primary material?

Type 5 Construction is characterized by its use of wood or other combustible materials as the primary structural components. This type of construction typically includes single-family homes and wood-framed buildings, where the exterior walls, floors, and roof are made primarily of wood. Due to the nature of these materials, Type 5 Construction is particularly susceptible to rapid fire spread, as wood ignites and burns easily, allowing fire to move quickly from one area to another.

In comparison, Type 1 Construction is made of non-combustible materials like steel or reinforced concrete, which provide superior fire resistance. Type 3 Construction features a combination of both combustible and non-combustible materials, while Type 4 Construction utilizes heavy timber elements that have better fire resistance properties compared to light-frame wood construction but still include some combustible materials. Therefore, the vulnerabilities of Type 5 Construction to fire make it the correct answer regarding susceptibility to fire spread due to its reliance on wood as the main material.