Hardiebacker vs Durock: What’s the Difference?

Whether renovating, building an addition, or starting from scratch, there’s a plethora of material choices to choose from. If you’re planning to install tile floors, walls, a backsplash, or a tub, shower, or fireplace surround, you may want to consider HardieBacker vs Durock. If you’re wondering what the differences are, we’re here to help!

Durock is a cement board reinforced with fiberglass while HardieBacker contains cellulose fiber so it is a fiber-cement board. Durock is lighter per square foot, more durable, more rigid, and less expensive, and can be used on walls, floors, ceilings, and both inside and out. HardieBacker is more flexible and cuts are easier and smoother, but it can’t be used on ceilings and isn’t recommended for exposed exterior use.

In this guide, we’ll explain what HardieBacker and Durock are and compare them based on key factors. Plus, we’ll take a look at WonderBoard and compare it with the other two materials and identify which is the best backer board for a shower. Our aim is to provide you with the information to make the best choices for your project.

Hardiebacker vs Durock

Hardiebacker vs Durock: Key Points

HardieBacker and Durock are two popular brands of cement backer boards for use with tile. Your local building supply store may carry one or the other, or both. To make it easier to decide which is better for your project, check out the table below.

 HardieBackerDurock
Material90% Portland cement and ground sand, and 10% cellulose fibers and a MoldBlock additivePortland cement, aggregate, and polymer-coated fiberglass mesh
FlexibilityMore flexibleMore rigid and less flexible
StrengthHas greater flexural strength and good compressive strengthIndentation strength is greater than 1250 PSI and nail-pull resistance is greater
Weight*0.42” thick weighs 2.6 lbs/ft² and 1/4” thick sheets weigh 1.9 lbs/ft²1/4” thick sheets weigh about 1.9 lbs/ft², 1/2” sheets weigh 2.4 lbs/ft², and 5/8” panels are 3 lbs/ft²
Thickness1/4" and 0.42” thick1/4", 1/2", and 5/8” thicknesses
Waterproof?Fiber content makes it more susceptible to moisture damage, so it is only rated as moisture resistant but the HydoDefense HardieBacker is 100% waterproofHighly moisture resistant and considered waterproof as it won’t break down even if continuously exposed to water
DurabilityGoodBetter
InstallationUse specified nails or screws, fill all seams or joints with tiling mortar and embed 2” fiberglass tape in mortar over seamsPre-drill or use self-tapping galvanized or stainless steel 14 to 20-gauge screws appropriate for framing and covering materials, use appropriate mortar with 2” fiberglass tape embedded over joints
UsesIndoor use only on floors, walls, and countertops as a tile backer, including vinyl productsIndoor and outdoor use including walls, floors, ceilings, countertops, and around fireplaces and wood stoves for tile and stone backing but not for vinyl flooring, ideal for skirting around exterior structures, soffits, backer for pillars, and other decorative elements
PriceA 1/4”x3’x5’ is $13.98 USD, 0.42”x3’x5’ is $17.68, and 0.42”x3’x5’ piece of HydroDefense HardieBacker is $27.87A 1/4"x3’x5’ is $11.31 USD and a 1/2"x3’x5’ is $13.48

*Weight specs are taken from the manufacturer’s product sheets.

What Is Hardiebacker?

What Is Hardiebacker

HardieBacker is a fiber cement board manufactured of 90% Portland cement and ground sand with the remaining 10% made up of cellulose fibers and a MoldBlock additive. Approved for internal use only, it is used as a backer board or underlayment for tile installation.

The panels are strong yet flexible and prevent moisture damage and mold growth. Panels are easy to score and snap or cut and have an embossed grid pattern for better tile adhesion and alignment.

HardieBacker 500 panels are 0.42” thick and weigh 2.6 lbs/ft² and typically are used for wall cladding on surfaces to be tiled instead of drywall. Their 1/4” thick sheets weigh 1.9 lbs/ft² and commonly are used on subfloors for floor tiles. However, the thicker sheets can be used on floors and the thinner ones on walls depending on the requirements. Both thicknesses are available in 3’x5’ or 4’x8’ sheets.

Hardie’s new HydoDefense backer board has waterproof protection throughout and also offers good tile adhesion. According to the literature, a waterproof membrane isn’t required between this HardieBacker board and the tile adhesive, thus saving time and money. As a homeowner though, you might prefer the membrane for added protection.

What Is Durock?

What Is Durock

Durock is a cement board used for floors, walls, and ceilings. Made of a slurry of Portland cement, aggregate, and polymer-coated fiberglass mesh, it is commonly used in wet or damp environments to replace drywall or plywood.

It has a smooth side for adhesives and a textured side better suited for mortar applications. Stronger and more rigid than other cement boards, it has a wide range of indoor and outdoor uses. Plus, it won’t separate and is resistant to moisture, mold, and mildew.

The 5/8” and 1/2″ thick panels are commonly used for walls, floors, and ceilings and are directly fastened to wood or steel studs or joists prior to tiling. The 1/4” thick sheets weigh about 1.9 lbs/ft², are usually 3’x5’, and are commonly fastened to subfloors for tiling, or on walls over existing drywall.

The 1/2” sheets weigh 2.4 lbs/ft² and come in 32”x5’, 3’x5’, 32”x8’, and 4’x8’ sizes. The 5/8” is 3 lbs/ft² and is available in 3’x5’ and 4’x8’ panels. Other sizes are also available as special orders.

What Is the Difference Between Hardiebacker and Durock?

Difference Between Hardiebacker and Durock

Cement boards are commonly used in areas that experience dampness or need more structural strength than paper-backed gypsum to support tiles or stonework. Availability and personal preference are often reasons for the choice of product used.

HardieBacker is known as a fiber cement board and Durock is a cement board. They are the most popular cement backer boards, and are commonly used for the same purposes, however, they aren’t the same. Comparing the two products using their manufacturer’s literature is the best way to determine which is better suited for a project, which is what we do.

Material

HardieBacker is 90% Portland cement and sand slurry and 10% cellulose fibers with a MoldBlock additive. It has a grid pattern embossed on one surface. It can easily be cut or scored with a utility knife and snapped like drywall, so there is little dust or mess. It is approved for interior use only and shouldn’t be used outside.

Durock is made of Portland cement slurry, aggregate, and polymer-coated fiberglass mesh. The fiberglass is used to provide greater strength and durability. This means the panels require a saw to cut and shape and some smoothing of cut edges, resulting in more dust and mess. Durock is approved for interior and exterior use.

Flexibility

HardieBacker is more flexible than Durock with 1/4″ thick panels being more flexible than thicker sheets. Durock contains an aggregate making it more rigid and less flexible, whereas HardieBacker contains ground sand and cellulose fiber, making it easier to bend.

Strength

HardieBacker identifies the flexural strength of its 1/4” board is 2100 PSI and a compressive strength of 7000 PSI. It also identifies its 1/2″ sheet strengths as 1700 PSI and 6500 PSI respectively too. According to Durock’s specs, their 1/4″ panels have a flexural strength greater than 1000 PSI and an indentation strength greater than 1200 PSI. Their 1/2” sheets are rated greater than 750 PSI and greater than 1250 PSI respectively, with 5/8” board being greater than 480 PSI and 1250 PSI.

Based on the literature, HardieBacker definitely has a greater flexural strength. However, compressive strength isn’t the same as indentation strength, so comparing the two as if they are the same isn’t accurate. HardieBacker is tested for compressive strength, Durock for indentation strength. Indentation strength, though, is a better indication of compression strength.

Durock has greater nail-pull resistance strength and can be used for high-impact abuse-resistant partitions, which indicates it is stronger in comparison to other products. Plus, Durock can span studs up to 24” centers but HardieBacker only up to 16”, so by interpretation, Durock would seem to be the stronger board.

Weight

Much of the internet literature falsely states that HardieBacker is lighter than Durock. According to James Hardie product literature, HardieBacker board that is 0.42” thick weighs 2.6 lbs/ft² and the 1/4” thick sheets weigh 1.9 lbs/ft². According to USG, the manufacturers of Durock, their 1/4” thick sheets weigh slightly less than 1.9 lbs/ft², 1/2” sheets weigh 2.4 lbs/ft², and 5/8” panels are 3 lbs/ft². So, by comparison, Durock weighs less per square foot than HardieBacker.

Thickness

HardieBacker is available in thicknesses of 1/4″ and 0.42” while Durock comes in 1/4″, 1/2″, and 5/8” thicknesses. The 1/4″ cement board is recommended for horizontal applications where it is supported, and the thicker material can be attached directly to the studs for vertical applications.

Waterproof?

HardieBacker is typically installed with a protective waterproof membrane to prevent moisture transfer. The panels contain a MoldBlocker additive, making them mold and mildew-resistant. The new HydoDefense HardieBacker contains a waterproofing agent throughout, making it more resistant to moisture and the manufacturer claims it is 100% waterproof.

The installation guide for Durock identifies that it doesn’t require a waterproof membrane and has a low water absorption rate and that it is mold and mildew-resistant. The specs further identify that the cement board is vapor permeable but the board will maintain its integrity and strengths even if continuously wet. It won’t soften, swell, delaminate, disintegrate, or decay in water. For true waterproofing though, Durock recommends the use of a waterproof membrane. Additionally, Durock can be used for interior and exterior purposes.

Pro Note: Many installers use a waterproof membrane with all cement boards regardless of manufacturers’ claims since cement is known to wick moisture.

Durability

Durock can be used indoors or out and can withstand exposure to the elements and moisture better, making it the more durable choice. HardieBacker can only be used indoors and has good durability if installed with a waterproof membrane. JHardie’s HydoDefense backer board is more durable than their other lines but still isn’t as durable as Durock.

Installation

Durock can be scored with a heavy-duty carbide-tipped utility knife and snapped, but the break isn’t very accurate or neat – it works best with 1/4″ boards than thicker ones. Use a circular saw, angle grinder, rotary cutter, or jigsaw with masonry blades and a drill with masonry hole saw bits for accurate cuts. Cut edges commonly are abrasive until smoothed, so gloves may be helpful too. Use the smooth surface for mastic adhesive or the rough side or mortar.

Durock can be installed directly to wood or 20 gauge or heavier metal studs spaced at 12”, 16”, or 24” centers. Use corrosion-resistant screws or galvanized nails spaced at 6” or 8”. Joints should be taped with 2” wide glass-fiber tape that is alkali-resistant. Depending on the type of finishing material, a Type-1 organic adhesive or latex-fortified mortar is recommended for bonding.

HardieBacker is best cut with a carbide-tipped utility or scoring knife and snapped or cut with manual, pneumatic, or electric shears. JHardie installation instructions even recommend scoring holes and knocking them out with a hammer. The literature further states that high-speed power tools should never be used as the ground sand produces more silica dust which is linked to respiratory issues. Those who regularly install HardieBacker comment that scoring is fine for mid-board cuts, but anything within an inch or two of the edge will need to be cut with a power tool.

HardieBacker can be installed directly to plywood, wood studs, or 20 gauge or greater metal studs no more than 16” on center. Use appropriate nails or screws no more than 8” apart to fasten the backer board, keeping them 2” from corners and 3/8” from the edges. Joints should be filled with mortar or mastic adhesive with 2” wide alkali-resistant glass-fiber tape embedded in it. A waterproof membrane or vapor barrier may be required to meet local building codes.

Pro Note: Always follow the manufacturer’s instructions and local building codes. Wear eye protection and a quality well-fitting NIOSH-approved mask or respirator as concrete and silica dust have health concerns. Clean up dust and debris with a HEPA filter equipped vacuum or wet sweep to collect the most dust and debris – or do power tool cutting outside.

Uses

Durock can be used in wet or damp environments both inside and out. Typical it is used as a backer board for ceramic, glass, clay, porcelain, quarried, and brick tiles, but isn’t recommended as a backer for vinyl tile. It can be used in showers, baths, pools, steam rooms, and saunas, or for backsplashes, countertops, floors, ceilings, and behind and under wood stoves and fireplaces. Durock also can be used outside above and below grade for protective skirting around elevated structures and trailers, and as soffits and backing for masonry, stone, or stucco finishes.

HardieBacker has many similar interior uses to Durock, and can also be used with vinyl tiles. It isn’t recommended, though, for ceiling applications or around fireplaces or wood stoves.

HardieBacker board actually conducts heat according to JHardie technical support, so shouldn’t be used under or behind a fireplace or wood stove. Plus, HardieBacker isn’t recommended for exterior use, although their 500 board can be used outside above grade levels. However, James Hardie assumes no responsibility for damage due to water infiltration. It should also be noted that its greater flexibility can cause issues if the backer board is poorly supported.

Both Durock and HardieBacker recommend that their thicker boards can be used for vertical and horizontal surfaces, while their thinner material should be used for horizontal surfaces. However, the thinner material can be used vertically over existing drywall or plywood sheathing materials.

Price

Prices of both HardieBacker and Durock vary from store to store and with ZIP or postal code, and even from day to day! In my local area a 1/4”x3’x5’ sheet of HardieBacker is $13.98 USD and a 0.42”x3’x5’ is $17.68, while a 0.42”x3’x5’ piece of HydroDefense HardieBacker is $27.87. A 1/4″x3’x5’ sheet of Durock is $11.31 USD and a 1/2″x3’x5’ is $13.48. The prices are reflective of larger and thicker sizes too. So, overall, Durock is less expensive than HardieBacker.

Durock vs Wonderboard vs Hardibacker

Durock vs Wonderboard vs Hardibacker

HardieBacker is a fiber-cement tile backer board, Durock is cement with fiberglass backer, and WonderBoard-Lite is also a fiberglass-reinforced cement board but contains expanded polystyrene (EPS) beads. All 3 products can be used inside as an underlayment to support tile, brick, and stone work on walls, floors, and countertops. Only Durock and WonderBoard, though, offer stability for ceilings and exterior work.

The cement in the 3 types of boards dulls knives if scoring, and all produce lots of dust if a power tool is used for cutting, so wear protective gear. Durock is the most moisture resistant, followed by HardieBacker and then WonderBoard. Due to the EPS beads, WonderBoard literature states it is 20% lighter than the other products. However, a 1/2”x3’x5’ sheet weights about 2.9 lbs/ft², so it is actually heavier than the other two products. Additionally, WonderBoard needs to be secured every 4” to 6” vs every 6” to 8” for the other two boards.

The three backer boards all include Portland cement, and while HardieBacker and Durock have a similar smell, WonderBoard smells more like playdough due to the EPS beads. Durock is stronger and more durable, followed by WonderBoard, and then HardieBacker. A 7/16”x3’x5’ sheet of WonderBoard Lite costs $14.67 USD, a 0.42”x3’x5’ piece of HardieBacker $17.68, and a 1/2″x3’x5’ panel of Durock $13.48.

What Is the Best Backer Board for a Shower?

Best Backer Board for a Shower

Most showers and baths that are to be tiled require a solid backer that isn’t going to flex if someone leans against it when cleaning it or showering. So, the best backer is a rigid cement-based backer board. The two most popular are HardieBacker and Durock. HardieBacker is a fiber cement board and uses 10% cellulose fibers for filler while Durock is a true cement board reinforced with fiberglass.

The fiberglass helps make Durock stronger, less flexible, and more water resistant, and according to both manufacture’s specs, it is lighter. It can also be used on floors, walls, and ceilings, meaning one product for the whole enclosure, not two separate materials. While HardieBacker may be easier to score and break, most pros use power tools for accuracy and to make cleaner cuts.

It should be noted, too, that many tubs and showers are 3 feet wide or less by 5 feet long, which is why both manufacturers produce 3’x5’ sheets, thus minimizing cuts. Additionally, Durock is less expensive than HardieBacker for similar thicknesses. So, while the choice may be personal preference and availability, Durock is the better backer for a shower.

Conclusion

Both Durock and HardieBacker have similar interior uses, but they are not the same. One is a true cement board with fiberglass reinforcing and the other is a fiber cement board since it contains cellulose fibers. Durock is more rigid, durable, and stronger and can be attached to studs at 24” centers or less, and used for ceilings and for exposed exterior applications.

HardieBacker, however, can be fastened only at 16” centers or less as it is more flexible, but it isn’t recommended for ceiling or exposed exterior locations. Durock is also lighter and less expensive too, while HardieBacker gives a smoother cut line. Availability and personal preference seem to be the main reason for selecting one over the other. Hopefully, we’ve provided you with the information needed to make the best choice for your project.

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