Deck-O-Seal® 3460005 5 gal Deck-O-Shield™ Concrete Deck/Waterfall and Natural Stone Sealer. Deck-O-Shield is a ready-to-use, water based sealer/water repellant for natural stone, concrete and masonry surfaces. Deck-O-Shield is designed for use as a sealer/water repellent on waterfalls in or around swimming pools; the product will limit the penetration of water into structurally sound, crack-free surfaces. The product also can be used as a sealer/water repellant for natural stone decks, walkways, or patios; virtually any area located near or around swimming pool areas. Surfaces treated with Deck-O-Shield will inhibit the penetration of salts, reducing "whitening" or staining.