Dampproofing on below-grade masonry foundation walls shall extend from the top of which structure to the finished grade?

The correct answer indicates that dampproofing on below-grade masonry foundation walls must extend from the top of the footing to the finished grade. This is essential because the footing serves as the base of the foundation, and it is the point at which the below-grade walls meet the ground. Proper application of dampproofing starting at the footing ensures that moisture from the surrounding soil does not penetrate the foundation walls, which can lead to structural damage and deterioration over time.

By extending the dampproofing from the footing to the finished grade, the integrity of the foundation is preserved, and it helps prevent water intrusion that can result from hydrostatic pressure against the foundation walls. This practice is critical in areas where water can accumulate around the foundation, making it imperative that moisture management strategies, such as dampproofing, are correctly applied from the lowest point of the structure to the surface.

Other options do not address the specific point where dampproofing should begin. For instance, starting at the foundation walls or the concrete slab does not account for the important area below grade where the risk of moisture penetration is highest. Ground level, while indicating the surface, does not articulate the necessity of protecting the foundational elements starting where they interact with humid soil conditions.