Trusted since 1997. Backed by the best warranty in the business. For more than 20 years, RadonSeal has been providing unbiased expertise, unparalleled service, and professional quality concrete and masonry sealers, cleaners, and repair kits. RadonSeal Deep Penetrating Concrete Sealer is a water-based, reactive sealer, for cementitious substrates that is guaranteed to work - forever. RadonSeal's proprietary formulation deposits premium-grade, reactive silicate up to 4 inches into concrete. Once inside, RadonSeal reacts to form a crystalline structure, blocking the capillary tracts - essentially plugging the concrete's pores with an immovable mineral. Results are permanent! Negative-side hydrostatic pressure will not budge it. Harsh chemicals cannot break it down. Once cured, RadonSeal will greatly reduce the transmission of water vapor, water seepage, and even radon gas. RadonSeal reduces efflorescence and eliminates concrete dusting. Treated surfaces are measurably stronger, denser, and resistant to scratching, and scaling. RadonSeal is suitable for concrete floors and walls, indoors or outdoors. Ideal for basements where moisture or radon are a concern. Eliminate the damp feel and musty odors in your cellar or crawl space. Use on concrete slabs, garage floors, foundation walls, parking structures, and warehouse and factory floors. Prevents concrete pitting and spalling due to freeze-thaw and road salts. Treated surfaces are suitable for paints, adhesives, tiles, and overlays. Safe and easy spray-on application, non-toxic, non-flammable, will not harm vegetation or pets. Approx. coverage per 5-gallon pail: Poured Concrete - 1000 sq. ft. Use RadonSeal Standard on interior concrete less than 20 years old and outdoor concrete older than 3 years. Use RadonSeal Plus on interior concrete more than 20 years old, outdoor concrete more than 3 years old, and concrete blocks or cinder blocks. Concrete is porous - Seal it!