HardieBacker™ 1/4'' Cement Board with Moldblock™ Technology

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1. LIMITED WARRANTY:

James Hardie Building Products, Inc. ("Hardie") warrants, (for installation within the U.S. and Puerto Rico) to the purchaser, the first owner of the structure to which the product is applied, and the first transferee of such structure (each a "Covered Person") that HARDIEBACKER™ Cement Board with MoldBlock™ technology (hereinafter "Product") is free from defects in materials and workmanship during the life of the Product subject to the terms and conditions of this Limited Warranty.

2. WHAT WE WILL DO:

If during the warranty period any Product proves to be defective, Hardie, in its sole discretion, shall replace or refund the original purchase price of the defective Product. If the original retail cost cannot be established by the Covered Person, the cost shall be determined by Hardie in its sole and reasonable discretion. Hardie's replacement of the defective Product pursuant to Section 2 of this Limited Warranty SHALL BE THE SOLE EXCLUSIVE REMEDY available to a Covered Person with respect to any defect. Hardie will pay for or reimburse labor costs.

3. WHAT YOU MUST DO/CONDITIONS OF LIMITED WARRANTY:

Warranty coverage under this Limited Warranty shall be subject to the following terms and conditions.

• A Covered Person must provide written notice to Hardie within thirty (30) days after discovery of any claimed defect covered by this Limited Warranty and before beginning any permanent repair. The notice must describe the location and details of the claimed defect and any additional information necessary for Hardie to investigate the claim. Photos of the Product, showing the claimed defect must accompany the notice. A claimant under this Limited Warranty must provide proof to Hardie that such claimant is a Covered Person as defined in Section 1 above.
• The Product must be installed according to Hardie's printed installation instructions and all building codes adopted by federal, state or local governments or government agencies and applicable to the installation.
• Upon discovery of a claimed defect, a Covered Person must immediately, and at a Covered Person's own expense, provide for protection of all property that could be affected until the claimed defect is remedied if applicable. Before any permanent repair to the Product, a Covered Person must allow Hardie or Hardie's authorized agent to enter the property and structure where the Product is installed, if applicable, and examine, photograph and take samples of the Product.

4. WHAT IS NOT COVERED:

This Limited Warranty does not cover damage or defects resulting from or in any way attributable to:

• The improper storage, shipping, handling or installation of the Product (including, without limitation, failure of the Product to be installed in strict compliance with the Conditions of Limited Warranty set forth in Section 3.B of this Limited Warranty) and/or improper installation of studs or other accessories;
• Further processing, modification or alteration of the Product after shipping from Hardie;
• Neglect, abuse, or misuse;
• Repair or alteration;
• Settlement or structural movement and/or movement of materials to which the Product is attached;
• Damage from incorrect design of the structure;
• Exceeding the maximum floor deflection;
• Exceeding the maximum designed wind loads;
• Acts of God including, but not limited to, tornados, hurricanes, floods, earthquakes, severe weather or other natural phenomena, (including, but not limited to, unusual climate conditions);
• Efflorescence or performance of any paints and/or coatings which are not Hardie and/or Hardie affiliated applied;
• Lack of proper maintenance; or
• Any cause other than material or manufacturing defects attributable to Hardie

5. LIMITATION OF LIABILITY:

IN NO EVENT SHALL HARDIE BE LIABLE FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING BUT NOT LIMITED TO, ANY CLAIMS OF PROPERTY DAMAGE, BASED UPON BREACH OF WARRANTY, BREACH OF CONTRACT, TORT, OR ANY OTHER LEGAL THEORY. Some states do not allow the exclusion or limitation of incidental or consequential damages, so the above limitation may not apply to you.

6. ENTIRE AGREEMENT:

This Limited Warranty contains and represents the only warranty extended by Hardie for the Product. No employee or agent of Hardie or any other party is authorized to make any other warranty in addition to those made in this Limited Warranty. This Limited Warranty gives you specific legal rights and you may also have other rights which vary from state to state.

7. HOW TO OBTAIN WARRANTY SERVICE:

For warranty services call 1.866.375.8603 or write Warranty Department, James Hardie Building Products, Inc., 10901 Elm Avenue, Fontana, California 92337.

• Where do I purchase HardieBacker™ board?
• How do I cut HardieBacker board?
• Where can I get a carbide score and snap knife?
• Which side goes up, smooth or rough?
• What subfloor should HardieBacker board be installed over?
• Why do I have to use thinset between HardieBacker board and the subfloor?
• What do you mean by ''modified thinset''?
• Can I use liquid nails or glue with HardieBacker board?
• What is the correct fastener pattern for installing HardieBacker board?
• What type of fastener do you recommend for floor and wall applications of HardieBacker board?
• Why can't I get screws to sit flush with the HardieBacker board?
• Why do I have to tape the joints?  What is the purpose of the 2'' wide tape?
• Where can I get the 2'' wide high-strength alkali-resistant glass fiber tape?
• Can I put HardieBacker board over linoleum or vinyl composite tile?
• Can HardieBacker 1/4'' board be used in a shower wall application? Is a vapor barrier required?
• Can HardieBacker 1/4'' board be used for floor tile applications?
• Can I use HardieBacker board as a fireplace facing?
• Can I use HardieBacker cement board in an exterior application?

Q. Where do I purchase HardieBacker™ board?

A: Use the online James Hardie preferred dealer locator or call customer service at 1-888-JHARDIE for your closest sales representative.

Q. How do I cut HardieBacker board?

A: HardieBacker board may be cut with a carbide-tipped scoring knife, utility knife, or cutting shears (manual, electric or pneumatic).

Q. Where can I get a carbide score and snap knife?

A: Home Depot® stores and Lowe's Home Improvement Warehouses®.

Q. Which side goes up, smooth or rough?

A: Either is acceptable, but we recommend that the smooth side with the nailing pattern of every 8" on center go up.

Q. What subfloor should HardieBacker board be installed over?

A: The minimum subfloor specified is 5/8" exterior grade plywood or 23/32'' exterior grade OSB subflooring. HardieBacker board must be installed in accordance with local building codes and the floor must be engineered not to exceed the L/360 deflection criteria, including live and dead design loads, for the specific joist spacing used. HardieBacker board is not designed for use over concrete.

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Q. Why do I have to use thinset between HardieBacker board and the subfloor?

A: Dry set (ANSI 118.1) or acrylic modified thinset (ANSI 118.4) is specified between the HardieBacker board and the subfloor to eliminate any deviations between our product and the subfloor. This decreases the probability of popping or cracking tiles due to deflection and air pockets.

Q. What do you mean by ''modified thinset''?

A: The modified thinset used with our product is a fortified cement-based mortar and should specifically conform to ANSI (American National Standards Institute) A 118.4. The thinset can be fortified in a pre-mixed powder form or with a liquid additive.

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Q. Can I use liquid nails or glue with HardieBacker board?

A: No. Where HardieBacker board is being installed over a code-complying subfloor for the attachment of tile, the board is installed over a 3/32''-1/4'' thick bed of bonding mortar and then nailed down. ''Liquid Nails'' is not a bonding mortar. It is a structural adhesive generally used to bond the subfloor to the floor joists just prior to nailing. It creates a very solid joint between the surface of the floor joist and the subfloor and aids in reducing floor squeak. The properties of Liquid Nails are such that it is applied via a tube in the form of a bead-like caulking. It is not trowelable like a mortar and therefore results in high ridges with unsupported areas that can deflect under load, resulting in cracked tile.

Where HardieBacker board is being installed directly to wood or metal framing, the use of a structural adhesive in addition to mechanical fastening can be used. However, the board must be forced into the structural adhesive almost immediately upon application to insure that no ridge or crown is formed. The creation of a crown or ridge will result in an additional thickness of mortar being applied to fill in the valley created by the crown. This will require a longer curing time and result in a weaker bond between the tile and the mortar and the underlayment. The use of a structural adhesive does not result in fewer fasteners being required.

Q. What is the correct fastener pattern for installing HardieBacker board?

A: Fasten HardieBacker sheets with proper nails or screws (as listed in ''Materials Required'' in the backer installation instructions) 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.

Q. What type of fastener do you recommend for floor and wall applications of HardieBacker board?

A: In compliance with the tile industry, James Hardie recommends 1-1/4'' long galvanized or stainless steel roofing nails (0.121'' shank x 3/8'' HD) or 1-1/4'' long corrosion resistant ribbed waferhead screws (No. 8-18 x 3/8'' HD).

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Q. Why can't I get screws to sit flush with the HardieBacker board?

A: The screws that you are using do not have the power to rout out the material in order for the screw head to sit flush. Be sure to use the specified screws (1-1/4'' No.8-18 by 3/8'' HD Hi-Lo S or S-12 for metal studs, ribbed phil wafer head, self drilling, corrosion-resistant screws). If you continue to have difficulties, we recommend switching to 1-1/4'' galvanized roofing nails

Q. Why do I have to tape the joints?  What is the purpose of the 2'' wide tape?

A: The tape will help disperse any movement of the substrate, therefore decreasing the probability of popping or cracking tiles along the seams.

Q. Where can I get the 2'' wide high-strength alkali-resistant glass fiber tape?

A: Home Depot stores and Lowe's Home Improvement Warehouses.

Q. Can I put HardieBacker board over linoleum or vinyl composite tile?

A: Yes, Hardiebacker can go over linoleum or vinyl composite tile. Even though you may go over vinyl composite tile, James Hardie does not recommend you install HardieBacker board over cushioned vinyl. Follow HardieBacker floor installation instructions for complete details.

Q. Can HardieBacker 1/4'' board be used in a shower wall application? Is a vapor barrier required?

A: Yes, HardieBacker 1/4'' cement board may be used in a shower. However, we recommend HardieBacker 1/2'' if you need to make a smooth transition to drywall. The board must be mechanically fastened every 8'' on center to the wood or metal studs spaced a maximum of 16'' on center. A vapor barrier is needed if required by local building codes.

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Q. Can HardieBacker 1/4'' board be used for floor tile applications?

A: Yes, both HardieBacker 1/2'' and 1/4'' board may be used for floor tile applications. If additional height is not required for transition, consider HardieBacker 1/4'' board — which has more compressive and flexural strength than any board on the market — even when compared to 1/2'' glass mesh cement boards. HardieBacker 1/4'' 3'x5' EZ Grid® sheet comes with a recessed fastener pattern for even easier installation.

Q. Can I use HardieBacker board as a fireplace facing?

A: Yes, HardieBacker board can be used as a fireplace facing. HardieBacker 1/4'' board can be used as a component in a 1-hour fire resistive construction when installed in compliance with National Evaluation Report NER-405. HardieBacker boards are recognized as non-combustible, when tested according to ASTM E 136.

Q. Can I use HardieBacker cement board in an exterior application?

A: In accordance with National Evaluation Service Report NER-405, HardieBacker board is recognized only as an interior substrate.

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Installation Guide

Download Installation Instructions [ PDF ]

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Click Here to View Installation Video

Cement Backerboard for Walls,
Floors and Countertops

90% Premium Portland Cement and Sand
Backed by a Lifetime Limited Warranty

Cutting HardieBacker™ Board

• Use a straight edge as a guide to score the board’s face and snap upward along the score line. We recommend using a carbide-tipped scoring knife, but a utility knife may also be used. The use of shears (manual, electric or pneumatic) is also acceptable.
• For cutouts and small holes, score around perimeter and break out from the face side with hammer.
• NEVER use high-speed power tools (e.g. saws, grinders, etc.) to cut James Hardie® products indoors as they may generate excessive silica dust.
• NEVER dry sweep – Use wet suppression methods or HEPA vacuum for clean-up.
• To further limit respirable silica exposures, wear a properly-fi tted, NIOSH-approved dust mask or respirator (e.g. N-95) in accordance with applicable government regulations and manufacturer instructions.

Countertop Installation

1. Ensure cabinets are level and secure
• Use minimum 1/2" exterior grade plywood or equivalent, positioned across the wood cabinet. Space between plywood supports is not to exceed 16" on center.


2. Determine layout of HardieBacker™ cement board
• Do not align HardieBacker cement board with plywood joints.
  
• Score and snap boards to required sizes and make necessary cutouts.
  
• We recommend an 1/8" gap from board edges.


3. Attach HardieBacker™ cement board to countertop
• Apply a supporting bed of dry-set mortar or modifi ed thinset to plywood with a 1/4" square-notched trowel. Mastic can also be used with a 5/32" V-notched trowel.
• Use the fastener pattern as a guide. Fasten HardieBacker cement board with specifi ed nails or screws (as listed in "Materials Required") every 8" over the entire surface. Keep fasteners 3/8" from board edges and 2" in from board corners.


4. Tape joints prior to tiling
• Prior to setting the tile, fill all joints with the same mortar used to set the tiles.
• Embed 2" wide high-strength alkali-resistant glass fiber tape in the mortar and level.

Floor Installation

We recommend 1/4" HardieBacker™ board for floor applications, unless 1/2" thickness is needed for transition.

1. Ensure subfloor is structurally sound
   
   On existing structures:
   • Ensure subfloor is not damaged. Replace any loose, warped, uneven or damaged sections of floor.
     
   • Make certain subfloor is a clean and flat surface.
   
   
   For all floors:
   • Use minimum 5/8 exterior grade plywood or 23/32 OSB with Exposure 1 classification or better, complying with local building codes and ANSI A108.11.
     
   • Joist spacing not to exceed 24" on center.
     
   • The floor must be engineered not to exceed the L/360 deflection criteria (L/720 for natural stone), including live and dead design loads, for the specific joist spacing used.
   
   
2. Determine layout of HardieBacker™ cement board
   • Stagger all HardieBacker cement board joints. Do not align with subfloor joints.
     
   • Never allow all four corners of boards to meet at one point.
     
   • We recommend an 1/8" gap between board edges.
     
   • Keep sheet edges 1/8" back from walls and cabinet bases.
     
   • Score and snap boards to required sizes and make necessary cutouts.
   
   
3. Attach HardieBacker™ cement board to subfloor
   • Apply a supporting bed of mortar or modified thinset to subfloor using a 1/4" square-notched trowel.
     
   • Embed HardieBacker cement board firmly and evenly in the wet mortar.
     
   • Use the fastener pattern as a guide. Fasten HardieBacker cement board with specified nails or screws (as listed in "Materials Required") every 8" over the entire surface. Keep fasteners 3/8" from board edges and 2" in from board corners.
     
   • Set fastener heads flush with the surface without overdriving.
   
   
4. Tape joints prior to tiling
   • Prior to setting the tile, fill all joints with the same mortar used to set the tiles.
     
   • Embed 2" wide high-strength alkali-resistant glass fiber tape in the mortar and level.

Wall Installation

1. Ensure framing is structurally sound
   • Must comply with local building codes and ANSI A108.11.
   • Use a minimum of 2" x 4" wood studs or 20-gauge metal studs, which must be straight, properly aligned and spaced a maximum of 16" on center.
   • In tub and shower enclosures, ensure that the framing is adequately reinforced at the corners.
   
   
2. Determine layout of HardieBacker™ cement board
   • Boards may be installed vertically or horizontally.
     
   • Edges of the board parallel to framing must be supported by a structural framing member.
     
   • Score and snap boards to required sizes and make necessary cutouts.
   
   
3. Attach HardieBacker™ cement board to framing
   • See applicable building codes regarding vapor barrier requirements.
     
   • Install boards 1/4" above floor, tub or shower pan and caulk accordingly.
     
   • Fasten cement board with specified nails or screws (as listed in "Materials Required") a maximum of 8" on center at all supports.
     
   • Keep fasteners 3/8" from board edges and 2" in from sheet corners.
     
   • Set fastener heads flush with the surface, without overdriving.
   
   
4. Tape joints prior to tiling
   • Fill all joints with mortar (see "Materials Required").
     
   • Embed 2" wide high-strength alkali-resistant glass fiber tape in the mortar and level.

HardieBacker™ board
delivers more compressive
and flexural strength than
any board on the market.

Finishing with Tile

1. Refer to ANSI A108 and the mortar and tile manufacturers' published application guidelines for complete tiling instructions.
   
2. Wipe the surface of HardieBacker™ cement board clean with a damp sponge just prior to adding mastic or mortar.
   
3. Spread the mastic or mortar with a notched trowel (Note: Please see "Materials Required" to see which setting material is required for your application.)
   
4. Twist or press and beat in tiles complying with ANSI A137.1.
   
5. Allow a minimum of 24 hours curing set time before grouting.

Finishing with Natural Stone

Natural stone often has hidden weaknesses which can result in surface cracks in finished floors. To reduce the risk of job failures, always consult The Marble Institute of America Handbook.

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

• Always follow the recommendations of the flooring material manufacturer.
  
• 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 floor must be engineered not to exceed the L/720 deflection criteria, including live and dead design loads, for the specific joist spacing used. The strength of your natural stone will have an impact on the ultimate performance of your flooring system.

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

Steam Room Application

HardieBacker™ board is recognized for use in residential steam rooms when installed over conventional framing and in accordance with HardieBacker board printed installation instructions, TCNA guidelines (Tile Council of North America Handbook, www.tileusa.com), and local building codes. Questions and concerns regarding design and construction should be directed to a knowledgeable professional.

Vinyl and Resilient Flooring

Materials Required
Fasteners

• Minimum 7/8" long galvanized or polymer-coated 18-gauge chisel point staples with 1/4" crown.
  
• Minimum 7/8" long galvanized ring shanked underlayment flooring 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.

Patch

• Use the cement-based, rapid-setting patching compound recommended by the floor covering manufacturer.
  
• Do not use a gypsum-based patch. Follow the patch manufacturer's instructions.

Preparation for Underlayment

1. Ensure subfloor is structurally sound and properly installed
   
   On existing floors:
   • HardieBacker cement board may be installed under or over Vinyl Composition Tile (VCT) and other resilient flooring. For best results, remove existing floor covering, especially if it is in poor condition.
     
   • If installing HardieBacker cement board over existing floor, ensure the floor is flat and floor covering is thoroughly adhered to the subfloor.
   
   
   On all floors:
   • Ensure subfloor is not damaged. Replace any loose, warped, uneven or damaged sections of floor.
     
   • Make sure subfloor is dry, level and fastened correctly. All fasteners must be countersunk or flush with the subfloor. All seams or other areas that are not level must be sanded flat.
     
   • Subfloor must be free of all debris, oil, grease, paint or other foreign substances.
   
   
2. Basements and crawl spaces
   • Crawl spaces must be well ventilated with a minimum of 18" 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" 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 on center around the perimeter and 6 on center in the field.
     
   • Keep fasteners between 3/8" and 3/4" from board edges and 2" in from board corners.
     
   • Fastener heads/crowns must be flush with or slightly countersunk a maximum of 1/16" below the surface.
   
   
3. Finishing surface and joints (not necessary for carpet or wood flooring)
   • If necessary, lightly hand-sand seams 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.
   
   

   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.

Basic Composition

90% Portland cement and sand with selected additives. Contains no asbestos, formaldehyde, gypsum, paper facing, or abrasive aggregate.

1/4" HardieBacker™ cement board:
Sheet size: 3' x 5' (EZ Grid® board) and 4' x 8'
Thickness: 1/4" Weight: 1.9 lbs. psf (9.3 kg/m2)
Complies with ASTM C1288 & ANSI A118.9

1/2" HardieBacker™ cement board:
Sheet sizes: 3' x 5' and 4' x 8'
Thickness: 1/2" nominal Weight: 2.6 lbs. psf (12.7 kg/m2)
Complies with ASTM C1288 & ANSI A118.9

Materials Required

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).

Tape

• 2" wide high-strength alkali-resistant glass fiber tape.

Fasteners

For floors and walls:

• Minimum 1-1/4" long corrosion-resistant roofing nails.
  
• Minimum 1-1/4" long No. 8 x 0.375" HD self-drilling corrosion-resistant ribbed waferhead screws.
  
• If compliance with ANSI A108.11 is not required, minimum 1" long No. 8 x 0.323" HD self-drilling corrosion-resistant ribbed buglehead screws may be used for floors.
  
• If applying 1/2" HardieBacker cement board over gypsum, use minimum 1-3/4" long corrosion-resistant roofing nails.

For countertops:

• Minimum 3/4" long corrosion-resistant roofing nails.
  
• Minimum 3/4" long ribbed counter sinking corrosion-resistant screws.
  
• 18-gauge corrosion-resistant polymer coated 3/4" staples with a 1/4" crown.
  
• For 1/2" HardieBacker cement board, use minimum 1-1/4" long corrosion-resistant roofing nails or ribbed countersinking screws.

For vinyl and resilient flooring:

• Minimum 7/8" long galvanized or polymer-coated 18-gauge chisel point staples with 1/4" crown.
  
• Minimum 7/8" 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.

Contractors and do-it-yourselfers trust HardieBacker™ cement board with MoldBlock™ technology to deliver superior moisture and mold protection. HardieBacker board doesn't contain any glass mesh or gypsum and its proprietary cement formulation delivers the ultimate in durabilty. HardieBacker board's dimensional stability, exceptional bonding surface, and moisture resistance make it the Total Wet Area Solution™.

Exclusive MoldBlock Technology

Mold protection is integrated throughout HardieBacker cement board. It passes both ASTM mold tests with a perfect score.

Ultimate in Durability

Proprietary 90% cement and sand formulation protects against water damage.

Exceptional Workability

Just score one side and snap upward. Cuts cleanly and fastens with common tools. Lightest cement board available.

Superior Tile Bond Strength

Exceeds industry specifications in ASTM tests for tile adhesion.

No Special Handling Required

Unlike fiber gypsum board, HardieBacker board does not have to acclimate to job site temperature and humidity prior to installation. Exclusive MoldBlock Technology Mold protection is integrated throughout HardieBacker cement board. It passes both ASTM mold tests with a perfect score.

Environmental Considerations

HardieBacker™ board's proprietary cement formulation and MoldBlock™ technology provide a moisture and mold-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 effi ciencies 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 fi bers, 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 Legacy Report NER-405
  
• City of Los Angeles Research Report No. 24862
  
• HUD Materials Release Nos.1263d and 1268c
  
• 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" HardieBacker cement board and 1/4" HardieBacker EZ Grid® cement board:
7000 psi (48 MPa)

1/2" HardieBacker 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 NER-405 and Intertek-ETLSemko website listings for recognized assemblies, or contact James Hardie's Technical Services at 1-800-9HARDIE (1-800-942-7343).

Warranty
Copies are available from James Hardie Building Products or wherever James Hardie® products are sold.