Drylok Paint in Basements: A Waterproofing Essential Drylok is a specially formulated masonry waterproofer designed to seal and protect basement walls from moisture and water seepage. Applied directly to concrete or masonry surfaces, it penetrates the pores to create a watertight barrier. Ideal for preventing mold, mildew, and musty odors, Drylok is a popular choice for homeowners looking to keep basements dry and more livable. For best results, apply to a clean, dry surface and follow manufactu