APPROVED MORTAR
For floors:

• Latex or acrylic modified thinset (complying with ANSI A118.4)
• Dry-set mortar (use between subfloor and backerboard only) (complying with ANSI A118.1)

For walls and countertops:

• Latex or acrylic modified thinset (complying with ANSI A118.4)
   
OR
 
• Type 1 mastic (complying with ANSI A136.1)

TAPE

• 2" wide alkali resistant, glass fiber cementitious backer unit reinforcing tape

APPROVED FASTENERS
For floors and walls:

• Minimum 1-1/4" long corrosion-resistant roofing nail
• Minimum 1-1/4" No. 8 by 0.323" head diameter ribbed counter sinking head, corrosion-resistant screws

For countertops:

• 3/4" corrosion-resistant roofing nails
• 18 gauge, corrosion-resistant, polymer coated 3/4" staples with a 1/4" crown

• Use a straight edge as a guide to score sheet's face with carbide tipped scoring knife and snap upward along the score line.
• Large cutouts - use a circular saw with a carbide tipped blade.

• Small holes - Drill with a carbide tipped masonry bit or score around perimeter and break out from the face side with a hammer. Smooth rough edges with a rasp or coarse sandpaper.
• Always wear approved safety glasses and dust mask.

On existing structures:

• HARDIBACKER ® sheets may be installed over Vinyl Composition Tile (VCT). However, remove all other existing floor coverings including cushioned vinyl.
• Ensure the sub-floor is not damaged. Replace any loose, warped or damaged boards.
• Make certain subfloor is a clean and flat surface.

For all floors:

• Use minimum 5/8" exterior grade plywood or 3/4" exterior grade OSB, complying with Local Building Codes and ANSI A108.11, over joists. Joists' spacing not to exceed a maximum of 16" on center.
• Deflection must not exceed L/360 of the span, including live and dead design loads.
• Do not use glue between grooves of tongue-and-groove plywood to allow for expansion and contraction of plywood.

• Stagger all HARDIBACKER ® sheet joints. Do not align with plywood joints.
• Never allow all four corners of sheets to meet at one point.
• Keep edge of sheets 1/8" back from walls and cabinet bases.

• Apply a minimum of 3/32" thick dry-set mortar or modified thinset to subfloor.
• Embed HARDIBACKER ® sheets firmly and evenly in the wet mortar. Leave 1/8" gap between sheet edges.
• Using the printed dots as a guide, fasten HARDIBACKER ® sheets with proper nails or screws (as listed in "Materials Required") every 8" over the entire surface. Keep the fasteners between 3/8" and 3/4" from sheet edges and 2" in from sheet corners.
• Set fastener heads flush with the surface without overdriving.

• Over existing structural joints.
• Where the floor changes in direction, such as in "L" shaped rooms.
• In the center of the floor where room exceeds 15' in any direction.
• Where changes occur in backing materials.

• Use minimum 1/2" exterior grade plywood positioned across the wood cabinet. Space between plywood supports is not to exceed 16" on center.

• Do not align HARDIBACKER ® sheets with plywood joints.
• Sheet ends and edges must be supported by perimeter framing.

• Apply a minimum 3/32" thick dry-set mortar, modified thinset or mastic to plywood.
• Using the printed dots as a guide, fasten HARDIBACKER ® sheets with proper fasteners (as listed in "Materials Required") every 8" over the entire surface. Keep the fasteners between 3/8" and 3/4" from sheet edges and 2" in from sheet corners.

NOTE: Consider HARDIBACKER ® 500 Ceramic Tile Backerboard for wall applications if material abuts 1/2" drywall.

• Must comply with Local Building Code and ANSI A108.11
• Nominal 2" x 4" wood or minimum 20 gauge metal studs must be straight, properly aligned and spaced a maximum of 16" on center.
• In tub & shower enclosures, ensure that the framing is adequately reinforced at the corners.

• Sheets may be installed vertically or horizontally.
• Score & Snap Sheets to required sizes and make necessary cut-outs.
• All joint ends and edges must be supported by a structural framing member or added blocking.

• When butting HARDIBACKER ® sheets to 1/2" drywall, tack 1/4" thick furring strips to each stud.
• In wet areas, install a moisture barrier (such as 15 lb. roofing felt) between studs and HARDIBACKER ® sheets.
• Install sheets 1/4" above floor, tub or shower pan.
• Fasten HARDIBACKER ® sheets with proper nails or screws (as listed in "Materials Required") every 8" around the perimeter and all supporting studs. Keep fasteners between 3/8" and 3/4" from sheet edges and 2" in from sheet corners.
• Set fastener heads flush with the surface, without overdriving.
• See detail drawings for installations with standard shower trays and molded bath or shower base.

• Expansion joints must be placed every 12 feet on center and at inside and outside corners.

NOTE: HARDIBACKER ® ceramic tile backerboard is not recommended nor approved for use in steam room or sauna applications.

Natural stones often have hidden weaknesses which can result in surface cracks in finished floors. To reduce the risk of job failures, always follow the instructions below and consult the Marble Institute of America Handbook.

In addition to the steps outlined under Floor Installation, the following is required:
 

• In addition to fasteners, adhere HARDIBACKER ® sheets to the subfloor with a modified thinset mortar.
• Marble and natural stones must have sufficient flexural strength for use in flooring systems.* Where the quality and strength of the stone is unknown, the subfloor deflection in a plane must not exceed L/720 of the span, including live and dead loads. The strength of your natural stone will have an impact on the ultimate performance of your flooring system.
• Always follow the recommendations of the flooring material manufacturer. Stone pieces exceeding 1/2" X 12" X 12" may require alternative procedures such as the use of medium mortar beds in lieu of a backerboard.

Failure to install and finish HARDIBACKER ® ceramic tile backerboard per James Hardie's written instructions may affect product performance and will void the warranty. Local building code requirements also apply HARDIBACKER ® ceramic tile backerboard does not add structural strength to a subfloor, and can only perform as well as the subfloor itself.

*Testing has shown that a minimum 2900 psi is preferable for flooring application.

Go To HardiBacker