INSTALLATION
SikaTile® underlayments, when properly installed in accordance with the following installation guidelines, provide years of protection for finished flooring. In addition to these instructions, installers shall also reference the most current edition of American National Standards Institute (ANSI), Tile Council of North America (TCNA) Handbook for Ceramic Tile Installations, The Marble Institute of America (MIA) Dimension Stone Design Manual, NWFA (National Wood Flooring Association) and manufacturer's instructions of selected setting materials, substrates, sub-floors, or other materials being used in total, or any part of, an installed floor system with SikaTile®. Consult your selected manufacturer of these previously mentioned components to ensure products are compatible with SikaTile® underlayments.
SURFACE PREPARATION
All surfaces must be between 40°F (4°C) and 90°F (32°C) and structurally sound (deflection not to exceed L⁄360 for ceramic and porcelain tiles and L/720 for natural stone), dry, clean, and free from oil, grease, wax, paint, old adhesives, sealers, and curing compounds. Any contaminants that inhibit proper bond must be removed. Substrate preparation should be completed following ANSI A108 AN-2 “General Requirements for Sub-surfaces.” All substrates should be plumb and true; surface deviation should not exceed 1⁄4" in 10’ or 1/8” in 10’ for large format tiles. Patching, leveling or areas requiring a mortar bed should be prepared using Sika® underlayments. Movement (expansion) joints should be provided to comply with TCNA method EJ171. Concrete must be free of any negative hydrostatic pressure and/or excessive moisture.
Mixing:
Dry Pack Mix: In a clean container, add approximately 3.5 quarts (3.3 liters) of clean, cool potable water. Then add the contents of the 50-lb (22.7-kg) SikaTile®-920 Underlay C. Mix thoroughly by hand in a mud box or wheelbarrow or with a slow speed mixer to a semi-dry, thick, trowelable consistency. Mixed material should be able to be formed into a ball without crumbling apart. Do not temper with additional water.
Slurry (Key) Coat: In a clean container, mix a small amount of SikaTile®-920 Underlay C and enough water to achieve a thick soup-like consistency.
Patching: In a clean container, add approximately 5 quarts (4.7 liters) of clean, cool potable water. Then add the contents of the 50-lb. (22.68 kg) SikaTile®-920 Underlay C. Mix thoroughly by hand or with a slow speed mixer to a smooth, thick, trowelable consistency. Do not temper with additional water. SikaTile®-920 Underlay C can be applied from 1/8 to 3” in a single pass application.
Application:
Read and follow manufacturer’s instructions before installation.
For concrete floors, first broom a uniform, bond coat of Portland cement paste mixture onto the floor. Immediately apply mixed SikaTile®-920 Underlay C by packing and screeding the material into place. It may be installed from 1 /2 to 3”. SikaTile®-920 Underlay C can be applied over most clean, dry sub-surfaces. It has an initial set in two hours and final set in five hours based on thickness and ambient conditions. Consult job specifications and industry standards for final thickness application.
For wood floors and counters, first apply roofing felt or building paper followed by minimum 2.5-lb. metal lath overlapping both the paper and the lath. Lath should be fastened every 8 inches. For unbonded mud bed, install the lath between the mortar bed. Apply SikaTile®-920 Underlay C same as for concrete floors, ensuring to press the mortar through lath with pressure to a final thickness of 1 /2 to 3”.
Refer to ANSI A108.1 industry standard for details on mortar bed installations.
Cleaning
Water is all that is needed to remove any uncured mortar from tiles, tools and equipment.
Coverage
50-lb. bag will cover 50 sq. ft at 1/8” thickness.
