Which construction type uses heavy timber?

The correct answer is associated with Type IV construction, which is known as heavy timber construction. This type of construction uses large wood members for structural support, which gives it its characteristic durability and fire resistance compared to lighter wood constructions. The heavy timber elements can be advantageous in terms of fire safety, as they are more resilient to burning than smaller wood members. Even though they may char, they often retain structural integrity longer than lighter materials, giving firefighters more time during fire events.

In contrast, Type II construction typically employs non-combustible materials but does not use heavy timber elements. Type III is characterized by a mix of combustible and non-combustible materials, usually with lighter wood members. Type V construction uses the lightest wood framing and is often the most vulnerable to fire due to the nature of the materials involved. Understanding the characteristics of these construction types is essential for fire investigators, as it influences the behavior of fire within the structure.