Which type of factory-built home may have an increased risk of a basement fire with the potential to vertically extend through other concealed spaces within the structure?

• A. Modular
• B. Precut
• C. Panelized
• D. Hybrid precut

Answer: (A)

Modular construction tends to create long, interconnected concealed spaces and junctions between modules that can act as vertical pathways for fire. When a basement fire starts, flames and heat can move through these hidden voids behind walls and floors and travel upward through the structure via the seams between modules or through chases created by mechanicals. Because the modules are built separately and then joined on site, fire-blocking can be inconsistent at module interfaces, allowing the fire to extend into upper levels and other concealed spaces more readily than in some other factory-built methods. This combination of large hidden cavities and less-continuous fire blocking makes basement fires in modular homes more prone to vertical spread through concealed spaces. Other construction types—precut, panelized, and hybrid precut—tend to have fewer such extensive hidden pathways, or they implement fire blocking differently, reducing the likelihood of rapid vertical spread in the same way.