RadonSeal Deep Penetrating Concrete Sealer is formulated to permanently seal, strengthen and protect, poured concrete, concrete blocks and cinder blocks. RadonSeal penetrates up to 4 in. into the concrete and reacts to form a mineral, greatly reducing vapor transmission, water seepage and radon gas. Use RadonSeal Standard on indoor concrete less than 20 years old and outdoor concrete less than 2 years old. Ideal for basements where humidity and/or water seepage is a concern. Use on concrete slabs, garage floors, foundation walls, parking structures, warehouses and factory floors. Prevents concrete pitting and spalling due to freeze-thaw, road salts and chemicals. Safe and easy spray-on application for homeowners or contractors. RadonSeal does not alter the surface of the concrete, it remains suitable for paints, adhesives and overlays. Approx. coverage per 5 Gal. pail: Poured Concrete - 1000 sq. ft., Concrete Blocks - 500 sq. ft., Cinder Blocks - 400 sq. ft. Color: Flat/None.