Rainy weather often reveals the leaks and other moisture problems lurking in basement spaces, so anything you can do now to waterproof your underground bonus area will preserve its comfort and character. A great way to finish off a below-grade space in water resistant style is with BEHR Basement & Masonry Waterproofing Paint.  Developed with Nanoguard technology, this new surface solution uses tiny nano particles to fill the voids created by larger ones, helping to prevent water penetration and moisture buildup in your basement. The alkali-resistant paint formula is also super strong, withstanding up to ten pounds of water pressure per square inch, equivalent to 22 feet of standing water.
BEHR Basement & Masonry Waterproofing Paint is formulated to prevent water penetration and moisture buildup in both above and below-grade walls, masonry and retaining walls, cinder and concrete blocks, and stucco and brick. This smooth, flat finish is water-based and available in 32 custom colors and limited computer color matching selections. Look for it in both gallon and five-gallon containers at your local Home Depot.