Sealers Approved for Contact with Potable Water
Sealers for concrete and masonry
Thoroseal
A cement-based, waterproof coating for concrete and masonry. It is NSF approved for sealing concrete or masonry tanks storing potable water. It is also used to seal the concrete base of culvert tanks. To waterproof such a tank it is typically used in conjunction with another product, ACRYL 60, which improves the adhesion of the sealer to the tank. I have used this product to seal precast concrete septic tank cisterns. Thoroseal is manufactured by Chemrex.
In Tucson it is available from Border Products: (520) 623-4100
www.chemrex.com
Cement Slip (aka Cement Slurry or Nil)
NSF 61-certified Portland cement mixed with water to form a thin paste (no sand or gravel added). It is used to seal cement, masonry, and ferrocement tanks. Apply the slip to a 1/4-inch thickness with a trowel on the same day the concrete tank is poured or plastered. Cover the tank with a tarp after the slip has been applied to keep humidity in the tank high and to prevent the slip from drying too fast and cracking. When the slip is firm, but still green, spray it lightly with water or set a bucket of water in the tank to enhance humidity, and cover the tank again with plastic or a tarp. Keep the slip moist and covered (shaded from the sun) for three weeks for thorough curing.
AMES Blue Max
A special blend of adhesive, high-strength elastomeric liquid rubber. It is a new impenetrable rubber technology for waterproofing in extreme wet situations such as flat roofs, below-grade foundations, basement walls, cisterns, water troughs, catch basins, ponds and fountains. Technicians for Sustainability uses it to seal the interior of their steel culvert tanks set in a concrete base. It can be ordered at many ACE Hardware locations.
www.amesresearch.com/bluemax.htm
Antihydro and Antihydro R
Admixtures of organic and inorganic chemicals used to waterproof concrete and increase its workability, strength, hardness, and durability. According to the manufacturer, mixing Anti-hydro within a concrete mixture produces impermeable concrete that is hard, non-dusting & safe for potable water.However, I was not able to obtain information from the manufacturer on what entity approved the products’ use with potable water.
Anti-hydro is intended for use in temperatures below 850F. Anti-hydro R is intended for use in temperatures exceeding 850F. Anti-hydro products are manufactured by Anti Hydro International, Inc.
www.anti-hydro.com
XYPEX HD-150
A concrete waterproofing coating approved by NSF for use in potable water tanks and cisterns. It must be applied to bare concrete only. According to a representative of the manufacturer, XYPEX HD-150 is marketed for homeowners, though it is the same product as XYPEX Concentrate which is marketed to concrete contractors. XYPEX HD-150 is manufactured by XYPEX Chemical Corporation.
www.hi-dry.com/index.html
Sealers for gutters and for between different materials such as concrete/plastic and metal
Sikaflex-1A
A moisture-cured, single-component, polyurethane-based, non-sag elastomeric sealant. Can be used as an elastic adhesive between materials with dissimilar coefficients of expansion such as concrete and metal or plastic and metal. I’ve used it to seal seams in gutters and seams around downspout pipes entering tanks. It is also used in culvert tanks to seal the seam between the metal culvert and concrete base (after the concrete has been sealed with Thoroseal), and the spiraling seam of the culvert itself. It is USDA-approved and NSF-approved for potable water contact. Sikaflex-1A is manufactured by Sika Corporation. In Tucson it is available from Border Products: (520) 623-4100.
www.sikaconstruction.com/con/con-prod-name.htm#con.prod-sikaflex1a
AMES Blue Max
A special blend of adhesive, high-strength elastomeric liquid rubber. It is a new impenetrable rubber technology for waterproofing in extreme wet situations such as flat roofs, below grade foundations, basement walls, cisterns, water troughs, catch basins, ponds and fountains. Technicians for Sustainability uses it to seal the interior of their steel culvert tanks set in a concrete base. It can be ordered at many ACE Hardware locations. www.amesresearch.com/bluemax.htm
Sealer used to coat a variety of materials
#432 Urethane is a liquid-applied, single-component, moisture-cured polyurethane coating, designed to form a tough rubber membrane impervious to moisture. Once cured, it allows expansion and contraction over a variety of surfaces, so it could be used to coat concrete and metal. It conforms to B.S. 6920 for use in contact with water intended for human consumption. #432 Urethane is NSF certified and is manufactured by GlobalShield, Inc.
www.roofs-online.com or
www.global-shield.com
