Bostik Black-Top is a liquid, rubber-based, fabric-reinforced, roller-applied, flexible waterproofing and anti-fracture membrane. Use Black-Top as a waterproofing and/or anti-fracture membrane over properly prepared concrete; structurally sound, exterior grade plywood (interior/dry use only); cementitious backer board; and existing, well-bonded ceramic tile or cement terrazzo prior to the installation of ceramic or stone tile.
6 gallon pail covers 250 ft2
Application as a Membrane: As a waterproofing membrane: Pre-treat all cracks (1/8″ or less), by applying a double application of fabric and liquid. See Antifracture/Crack Suppression Membrane instructions below for additional information.
Once the surface of the pre-treated area has dried to the touch, apply a liberal coat of the liquid, to a slightly wider area than the width of the fabric, with a heavy-nap roller to achieve a good saturation of the substrate. Immediately and firmly embed the fabric into the liquid until there is complete saturation of the material; apply a liberal second coat of liquid to achieve a flat, reinforced, uniformly thick membrane (approximately 20 mils). Lap fabric a minimum of 2″ at the seams. Let liquid dry to the touch in all areas. Apply a final top-coat of the liquid to the entire area being treated. Nominal dry thickness is approximately 20 mils.
Special Precautions: Protect membrane from traffic and water exposure until fully cured. In critical installations, flood tests are required prior to application of tile or stone. Allow membrane to cure fully before testing. Approximately 7 days at 72°F (22°C) and 50% Relative Humidity, or longer in colder weather.
As an Antifracture/Crack Suppression Membrane: For cracks (1/8″ or less) and changes in plane, etc. Apply a liberal coat of the liquid, to a 4″ wide strip on both sides of the area being treated (8″ wide strip), with a heavy-nap roller to achieve a good saturation of the substrate. Immediately and firmly embed 6″ wide reinforcing fabric into the liquid until there is complete saturation of the material; apply a liberal second coat of liquid to achieve a flat, reinforced, uniformly thick membrane (20 mils), liquid dry to the touch in all areas (approximately 2 hours at 72°F (22°C) and 50% Relative Humidity). The membrane should be applied to both sides of the crack/joint a minimum of the width of the tile being installed (i.e. a 12″ tile should have a minimum 24″ wide membrane).