Installation Guide

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2 | Basements and crawl spaces
• Crawl spaces must be well ventilated
with a minimum of 18 in between the
ground and joists. A vapor barrier over
the ground is required.
Underlayment Installation
1 | Determine layout of HardieBacker
®
cement board
• Install smooth side up.
• Install HardieBacker boards perpendicular to subfloor panels.
• Stagger all HardieBacker board joints. Do not align HardieBacker board joints with
subfloor joints
• Never allow all four corners of boards to meet at one point.
• Lightly butt the board joints. Do not leave a gap or force edges together.
• Join factory-cut edges together in the body of the floor.
• Keep board edges 1/8 in back from walls and cabinet bases.
2 | Attach HardieBacker boards to subfloor
• Fasten one board at a time. HardieBacker boards must be flush with subfloor
during installation.
• Begin the fastening pattern in a corner of the board, then fasten the two adjacent
edges. Return to the corner and fasten in a diagonal pattern from that corner until
the board is completely fastened.
• Place fasteners in a random, staggered pattern across HardieBacker board. Avoid
fastening in a straight line.
• Fasten HardieBacker boards with proper fasteners (as listed in “Materials
Required”) a maximum of 3 in on center around the perimeter and 6 in on center
in the field.
• Keep fasteners between 3/8 in and 3/4 in from board edges and 2 in in from
board corners.
• Fastener heads/crowns must be flush with or slightly countersunk a maximum of
1/16 in below the surface.
3 | Finishing surface and joints (not necessary for carpet or wood flooring)
• If necessary, lightly hand-sandseams to achieve a smooth transition between
boards. Avoid over-sanding. Sanding will generate significant respirable silica
dust and those in the immediate area must wear NIOSH-approved respiratory
protection (e.g. N95) in accordance with applicable government regulations.
• Thoroughly clean HardieBacker board surface to remove all debris prior to
patching.
• Using a wide flat trowel, apply a skim coat of patch (as listed in “Materials
Required”) to all seams, sanded areas, hammer indentations, holes, gaps,
gouges, chips and voids to achieve a smooth surface. Avoid building a ridge over
the seams by feathering the patch out several inches on both sides of the seams.
• Obtaining a perfectly smooth surface may require more than one coat of patch.
• After the patch has thoroughly dried, lightly sand or scrape off any surface
imperfections caused by the patch to achieve a smooth surface.
• Wait until patch is thoroughly dry before installing the floor covering.
4 | Flooring installation
• Prepared HardieBacker cement board surface must be free of all debris, oil, paint,
caulk, joint compound and other foreign substances.
• Do not install floor covering seams directly over the HardieBacker board seams.
• Install floor covering according to the adhesive and floor
covering manufacturers’ instructions.
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BASIC COMPOSITION
90% Portland cement and sand with
selected additives. Contains no asbestos,
formaldehyde, gypsum, paper facing, or
abrasive aggregate.
1/4 in HardieBacker cement board:
Sheet size: 3 ft x 5 ft (EZ Grid
®
board)
and 4 ft x 8 ft
Thickness: 1/4 in
Weight: 1.9 lbs. psf (9.3 kg/m2)
Complies with ASTM C1288 & ANSI
A118.9
HardieBacker
®
500 cement board:
Sheet sizes: 3 ft x 5 ft and 4 ft x 8 ft
Thickness: 0.42 in
Weight: 2.6 lbs. psf (12.7 kg/m2)
Complies with ASTM C1288 & ANSI
A118.9
MATERIALS REQUIRED
1| Mortar
For floors:
• Latex or acrylic modified thinset
(complying with ANSI A118.4).
• Dry-set mortar for use between
subfloor and cement board only
(complying with ANSI A118.1).
For walls and countertops:
• Latex or acrylic modified thinset
(complying with ANSI A118.4).
• Type 1 mastic (complying with ANSI
A136.1) (Not to be used in exterior
applications).
• For Exterior applications, follow
stone and mortar manufacturers
recommendations.
2 | Tape
• 2 in wide high-strength
alkali-resistant glass fiber tape.
3 | Fasteners
For floors and walls:
• Minimum 1-1/4 in (for interior)
& 1-3/4 in (exterior walls) long
corrosion-resistant roofing nails.
• Minimum 1-1/4 in (for Interior) &
1-3/4 in (exterior walls) long No. 8 x
0.375 in HD self-drilling corrosion-
resistant ribbed waferhead screws.
• If compliance with ANSI A108.11
is not required, minimum 1 in long
No. 8 x 0.323 in HD self-drilling
corrosion-resistant ribbed buglehead
screws may be used for floors.
SILICA WARNING: Refer to the product Safety Data
Sheet before use. Do not handle until all safety
precautions have been read and understood. Do not
breathe dust from the product Do not eat, drink or
smoke when using this product.
The hazard associated with fiber cement arises from
crystalline silica present in the dust generated by
activities such as cutting, rebating, drilling, routing,
sawing, crushing, or otherwise abrading fiber cement,
and when cleaning up, disposing of or moving the
dust. When doing any of these activities in a manner
that generates dust: (1) comply with the OSHA PEL for
silica dust and/or other applicable law, (2) follow James
Hardie instructions and best practices to reduce or
limit the release of dust; (3) warn others in the area
to avoid the dust; (4) when using mechanical saw or
high speed cutting tools, work outdoors and use dust
collection equipment; and (5) if no other dust controls
are available, wear a dust mask or respirator that meets
NIOSH requirements (e.g. N-95 dust mask). During
clean-up, use a well maintained vacuum and filter
appropriate for capturing fine (respirable) dust or use
wet clean-up methods - never dry sweep.
BK050905
• If applying HardieBacker 500 cement
board over gypsum, use minimum 1-3/4
in long corrosion-resistant roofing nails.
For countertops:
• Minimum 3/4 in long corrosion-resistant
roofing nails.
• Minimum 3/4 in long ribbed counter
sinking corrosion-resistant screws.
• 18-gauge corrosion-resistant polymer
coated 3/4 in staples with a 1/4 in
crown.
• For HardieBacker 500 cement board,
use minimum 1-1/4 in long corrosion-
resistant roofing nails or ribbed
countersinking screws.
For vinyl and resilient flooring: (Interior Only)
• Minimum 7/8 in long galvanized or
polymer-coated 18-gauge chisel point
staples with 1/4 in crown.
• Minimum 7/8 in long galvanized ring
shanked nails.
• Fasteners should be long enough to
reach the bottom of the subfloor, but not
penetrate it.
• Avoid using resin, rosin or cement-
coated fasteners that can discolor vinyl
flooring.
HardieBacker board delivers
more compressive and
flexural strength than any
board on the market.
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ENVIRONMENTAL CONSIDERATIONS
HardieBacker
®
board’s proprietary cement formulation provides a moisture
resistant wallboard and tile backer substrate that stands tough over time, reducing
the need for product replacement. James Hardie has demonstrated a commitment
to reducing energy consumption, while improving process efficiencies and waste
management. It avoids the use of environmentally damaging materials and uses
renewable resources that are abundant in the manufacture of HardieBacker
cement board. HardieBacker cement board does not contain any glass fibers,
gypsum, asbestos or formaldehyde. The company also focuses on water
conservation and attempts to recycle water and waste product as much as
possible during the manufacturing process.
RECOGNITIONS
HardieBacker cement board is recognized as an interior substrate by the following:
• International Code Council Evaluation Service ESR-2280
• City of Los Angeles Research Report No. 24862
• HUD Materials Release Nos. 1263 and 1268
• City of New York MEA No. 223-93M
• IBC 2509.2
• IRC R702.4.2
Consult these documents for additional information concerning conditions for use
in applicable jurisdictions.
*Cementitious Backer Unit/Fiber-Cement Underlayment
Compressive Strength Compressive Strength at Equilibrium Moisture Content
(ASTM D2394)
1/4 in HardieBacker EZ Grid
®
cement board: 7000 psi (48 MPa)
HardieBacker 500 cement board: 6500 psi (45 MPa)
Non-Combustibility HardieBacker cement board is recognized as non-combustible
in accordance with ASTM E136.
Surface Burning Characteristics When tested in accordance with ASTM method
E-84: Flame Spread – 0, Fuel Contributed – 0, Smoke Developed – 5.
Fire Rated Assemblies HardieBacker cement board may be used as a component
in one-hour fire-resistive wall construction; consult ESR-2280 website listings
for recognized assemblies, or contact James Hardie’s Technical Services at
1-800-9HARDIE (1-800-942-7343).
HARDIEBACKER WARRANTIES
INTERIOR APPLICATIONS
The HardieBacker cement board limited lifetime warranty covers both the
product and replacement labor for the life of the product. Download a copy of the
HardieBacker limited lifetime warranty from hardiebacker.com or obtain one from
wherever James Hardie product are sold.
EXTERIOR APPLICATIONS
James Hardie offers a limited 10 year warranty for Hardiebacker 500 cement
backerboard installed in exterior applications in HardieZone HZ10 regions only.
To find out the HardieZone designation for your ZIP code, go to HardieZone.com