What should the top of ducks or equipment that are subject to foot traffic be insulated with?

• A. Flexible insulation
• B. Rigid insulation
• C. Vapor barrier only
• D. No insulation needed

Answer: (B)

When a surface will be walked on or bear load, the insulation needs to hold up under pressure while still providing thermal resistance. Rigid insulation is best here because its solid boards don’t crush under foot traffic, so the insulation layer stays continuous and its R-value remains effective for the ducts or equipment tops. Flexible insulation can be compressed by foot traffic, reducing its R-value and leaving gaps. A vapor barrier alone doesn’t provide insulation, and doing nothing would leave heat flow unprotected.