It has excellent hide and blocks most stains and odors. Mold Blocking Primer is formulated for use on non-porous interior and exterior applications and may be applied in factories, warehouses, storage facilities, refrigerated storage facilities, office buildings, residential living, schools, hospitals, veterinary care facilities, elderly care facilities, prisons, and correction facilities, wash houses, restaurants, fitness centers and locker rooms, attics, basements, window frames, bathrooms, wall cavities, baseboards, sub-floors, and tabletops.