Fiberock Underlayment and Tile Backerboard ® Installation Guide Interior Floors, Walls and Countertops.
Fiberock Underlayment and Tile Backerboard ® Fiberock underlayment and tile backerboard are all purpose substrates engineered to meet floor underlayment and wall tile-backing needs throughout a home. Under resilient flooring, Fiberock underlayment provides a hard surface that’s smooth and flat with no bumps or ridges to show through or affect finished floor covering.
Introduction – Fasteners Installing Fiberock panels is quick and easy. Just follow the simple installation steps in this booklet to create a perfect base for tile or floor coverings. Wall Application: For steel stud applications (20 ga. or equivalent), use 1-1/4" or 1-5/8" Durock screws for steel framing (or equivalent). For wood stud applications, use 1/4", 1-5/8" or 2-1/4" Durock screws for wood framing (or equivalent) or 1-1/2" hot-dipped galvanized ring shank roofing nails.
Handling – Protect panels from the elements with adequate covering during delivery and storage. – Store panels flat on an even, dry surface. Allow panels to acclimate to temperature and humidity at job site prior to installation. – Handle panels in an upright position to prevent breakage. Wall Applications: Maximum stud spacing: 16" o.c. Framing shall be designed (based on stud properties alone) not to exceed L/360 deflection for tile, L/240 for surfaces that will be painted.
Preparation Crawl-Space Requirements Ensure that subfloor and structure are within tolerances specified by floor covering manufacturer. Inspect subfloor for even, flat surface before installing underlayment. Uneven end edge joints and variations in subfloor panel thickness may telegraph through underlayment in vinyl applications. Sand uneven joints, if necessary. Ensure that subfloor is flat between framing elements. If subfloor panels appear to buckle, correct by adding blocking or cleats under floor.
Cutting and Laying Out Panels Cutting Panels For more cutting techniques, consult your USG Fiberock representative. Maintain temperature and humidity in space approximate to that of normal occupancy prior to, during and after installation. Install underlayment, with fastener marks up. Panels may be cut by scoring and snapping with a utility knife and straight edge, or by sawing, working from the face side.
Floor Application Ceramic Tile Finishing Joints Underlayment or Tile Backerboard Panel Application Apply Type 1 organic adhesive with 5/32" v-notched trowel, latex-fortified mortar with 1/4" square-notched trowel. Comb out adhesive or mortar in straight, parallel rows (as shown below) and immediately cover with panel. Adhere panels to subfloor, one panel at a time.
Floor Application Working a small area at a time, set tile with a slight twisting motion and press into place. Avoid adhesive buildup on tile edge and in grout space. Keep tiles aligned so joints are straight and uniform. Use tile spacers if desired. 1/4” Note: Refer to ANSI A108.4 or A108.5 for complete tile installation instructions. Refer to setting material manufacturer for specific information related to trowel type and size, proper tile type and size, mixing instructions, and set and cure times.
manufacturer's guidelines for setting times before allowing traffic on the finished floor. Follow floor-covering manufacturer's recommendations for preventive maintenance, cautions and procedures. Correcting Joint Imperfections Use Durock patching compound or equivalent sparingly to fill wide joints, repair any surface voids and correct joint lippage (panel edge sitting above or below the floor plane).
Wall and Ceiling Application Glued-Down Wood Flooring Shim Installation of engineered or solid hardwood glued-down flooring must strictly follow manufacturer's instructions. Follow recommendations above for underlayment installation. Place a 1/4" spacer strip or shim around lip of bathtub or shower pan to hold bottom edge of panel off the fixture. Joint Finishing In areas that will be tiled, finish joints with Durock tile backer tape and latex-fortified mortar or Type I mastic.
Countertop Application Cover plywood base with Durock tile membrane, 15 lb. felt or 4 mil polyethylene and attach with 1/4" galvanized staple. Determine whether floor is level by measuring distance to desired tile height on both sides of area to be tiled. If there is a difference (i.e., the floor is lower on one side), lay one vertical row of tile from desired tile height to low point of floor. Affix tiles with tile-setting materials.
Trademarks The following trademarks used herein are owned by United States Gypsum Company or a related company: Durabond, Durock, Fiberock, Midweight, Plus 3, Sheetrock, USG, USG in stylized letters. Note Products described here may not be available in all geographic markets. Consult your United States Gypsum Company sales office or representative for information.
