BLOCKOUT SILOX is a silane/siloxane-based emulsion water-repellent treatment for use on mineral substrates such as brick, stone, concrete, and mortar. BLOCKOUT SILOX penetrates and provides water repellency by chemically reacting with the substrate. Treated substrates retain their original appearance and have excellent resistance to weathering. BLOCKOUT SILOX reacts with the atmospheric moisture or pore water present in the substrate, forming a tightly bonded hydrophobic lining within the pores. This process results in a hydrophobic treatment that inhibits water absorption into the substrate. The lining greatly lowers water absorption, while allowing the substrate to breathe.