Which construction type is known for its heavy-timber structural elements?

Type 4 construction is characterized by its use of heavy timber elements, which are typically solid wood beams and columns. This type of construction allows for large, open spaces within a building, making it suitable for warehouses, factories, and similar structures. The significant thickness of the wood used provides a degree of fire resistance, as heavy timber tends to char on the surface when exposed to flames, protecting the inner core of the material.

In contrast, other construction types utilize different materials and structural designs. Type 1 construction primarily involves non-combustible concrete and steel, which provide superior fire resistance but do not utilize heavy timber. Type 2 construction employs similar principles, focusing on non-combustible or limited-combustible materials as well, further diverging from the characteristics of heavy timber. Meanwhile, Type 5 construction, which often includes lightweight wood framing, lacks the robust features associated with heavy timber and is more susceptible to structural failure during a fire.

Understanding these distinctions helps reinforce why Type 4 construction's defining feature is indeed its heavy-timber elements.