Which type of construction involves heavy timber?

The correct answer is indeed the type that specifically features heavy timber construction, which is Type 4. This construction method is characterized by the use of large pieces of wood, typically greater than 5 inches in dimension, which create a robust structure. The use of heavy timber provides a high degree of fire resistance due to the thickness of the wood, which allows for slower burning rates compared to smaller timber sizes. This type of construction can be found in buildings like warehouses and multi-story structures where both strength and aesthetic appeal are desired.

Other types of construction methods, such as Type 2, Type 3, and Type 5, have different characteristics. For instance, Type 2 construction typically involves non-combustible materials with some fire-resistive features but does not specifically utilize heavy timber. Type 3 construction is usually defined as having a combination of wood and non-combustible materials, often resulting in a less resilient overall structure compared to heavy timber options. Type 5 construction is primarily composed of frame materials, which are smaller in dimension than those used in Type 4 and do not offer the same level of fire resistance. Understanding these distinctions is crucial for fire safety inspections and assessing the potential risks associated with different building materials.