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Ardex 8+9 Gray Rapid Waterproofing and Crack Isolation Compound

by Ardex
SKU 24796

Gray Rapid Waterproofing and Crack Isolation Compound 

Best-in-class, two-component, solvent-free, cement-based membrane. Comprised of an acrylic-based liquid compound and a Portland and other hydraulic cement-based powder, ARDEX 8+9 can be applied easily with a paint roller or a brush to produce a highly flexible, waterproof coating. This coating protects from topside water infiltration and provides an excellent bonding layer for ARDEX tile and stone mortars. When properly installed, ARDEX 8+9 reduces the risk of efflorescence and is IAPMO certified for use as a shower pan.


  • Rapid setting – tile in as little as 90 minutes
  • Flood test in 4 hours
  • Crack isolation up to 1/8″ (3 mm)
  • Excellent coverage – up to 300 sq. ft. for commercial unit and up to 100 sq. ft. for convenient kit
  • Available in Gray or White
  • Ideal for applications in commercial and residential bathrooms, showers and kitchens prior to the installation of tile and stone
  • For use in swimming pools*
  • Use for interior or exterior floors and walls+
  • Easy to apply with a roller or paint brush
  • A solvent-free blend of Portland cement and other hydraulic cements for the ultimate bond with ARDEX tile and stone mortars
  • Helps to prevent efflorescence from the substrate
  • Can be used in place of a shower pan liner


  • Requires a solid substrate that is clean, dry and free of oils, grease, wax, latex compounds, curing compounds, dust and all foreign matter. Do not install below 50°F (10°C) surface temperature
  • MIX 1 – Caulking Consistency - Mix a small amount of ARDEX 8+9™ to a lump-free caulk-like consistency for filling holes, gaps and joints. Always pour liquid into the mixing container first and then the powder. Working time is approximately 45 minutes at 70°F/21°C.
  • Crack Isolation - Use MIX 1 to fill around floor or wall penetrations, corner and floor/wall joints and dormant cracks up 1/8” before installing ARDEX SK MESH™. The unused portion of the trowel grade MIX 1 mixture can be blended back with the balance of the remaining powder and liquid for use in the next step, MIX 2
  • MIX 2 – Paint-able Consistency - Mix ARDEX 9 (powder) with one unit of ARDEX 8 (liquid). For best results, mix with an ARDEX T-2 Ring Paddle and a low speed drill. 
  • Always pour liquid into the mixing container first and then the powder.
    • Mix thoroughly to obtain a lump-free, pour-able mixture. Coat the entire area evenly with a paint roller or brush and allow thorough drying (30 to 45 minutes). A second layer is required to obtain a waterproof membrane, and must be applied at a 90° angle to the first coat