What material is used to separate the mudsill plate from the top of a concrete wall?

• A. Sill gasket
• B. Caulking
• C. Foam strip
• D. Plastic shims

Answer: (A)

Separating the mudsill from the top of a concrete wall uses a sill gasket. This compressible barrier sits on the concrete and provides a uniform bearing surface for the mudsill while preventing moisture from wicking up into the wood and reducing air leaks. It also helps smooth out minor irregularities in the concrete surface. Caulking is a sealant for gaps and joints, not a continuous load-bearing separation; foam strips can be used for insulation but aren’t the standard dedicated separation layer; plastic shims are rigid leveling pieces and don’t address moisture control. So the sill gasket is the best choice.