Which is a sign that a structure is susceptible to collapse?

• A. Doors stuck in shifted frames
• B. Discolored drywall at floor level
• C. Delaminated plywood
• D. Inverted fire patterns

Answer: (A)

Structural movement and misalignment are strong indicators that a building may be nearing collapse. When the framing shifts under load, doors can no longer swing freely and become stuck or jammed in their frames. This binding isn’t just about the door itself; it shows the surrounding structural members—jambs, studs, and headers—have moved out of true and are deforming. That deformation is a sign that the structural system is failing to support loads as designed, increasing the risk of progressive collapse if conditions worsen or additional loads are applied.

Discolored drywall at floor level can point to moisture, water damage, or previous fire exposure, but it doesn’t directly indicate imminent failure of the structural system. Delaminated plywood reveals deterioration of wood panels, often from moisture or age, which is a concern for long-term safety but not a immediate, definitive sign of impending collapse. Inverted fire patterns relate to how a fire and smoke behaved during the incident and can inform fire travel and ventilation, but they don’t by themselves prove that the structure is about to give way.