Red Seal Carpenter Practice Exam

A sill gasket should be placed on top of a concrete foundation wall to isolate the bottom plate from the concrete. This is because a sill gasket acts as a barrier between the concrete and the wood, preventing any moisture or water from seeping into the wood and causing damage. It also helps to reduce any potential air leaks.

Options B, C, and D are incorrect. A filler strip is not typically used as insulation and may not fully protect the bottom plate from moisture or air leaks. A continuous bead of caulking may provide a temporary barrier, but it is not as effective as a sill gasket and may eventually crack or shrink. 25 mm of rigid insulation is also not as effective as a sill gasket and may not fully protect the bottom plate from moisture or air leaks.