Leakproof Basements Standard materials, good sense, and careful detailing will keep out the water for good. by Henri de Marne Wet basements and crawl spaces are the most common problems I see as a consultant, followed by attic moisture problems. And sometimes the two are related. But there is no excuse for a wet foundation in a new house. The marketplace is full of waterproofing systems, some adapted to residential housing from commercial applications. They come in a wide variety of materials, but have one thing in common: all are relatively expensive. Yet, available to contractors and builders everywhere is a system that is inexpensive, easy to apply, and foolproof. It requires no special skills, and causes no delays in delivery.