HardieBacker Vs. WonderBoard: 6 Differences (Comparison)


Photo: Andrew Hart / Flickr / CC BY ND 2.0

Moisture penetrates tiles and grout over time. So, to prevent mold and rot from working their way into a drywall surface behind your bathroom tiles, contractors and DIYers use cement backer boards in place of drywall.

Backer boards provide a structurally sound and moisture-resistant surface on which to mount your floor or wall tiles.

Many contractors regard cement-based backer boards as the wet area alternative to drywall boards, which contain gypsum and some wood products, both of which are susceptible to water damage and rot.

Therefore, you should use the products in bathrooms and shower enclosures on the floor or walls, under kitchen floors, and behind splashback tiles.

Furthermore, use them under entryway floors to protect against encroaching rainwater, and in laundry rooms, as washing machines often leak or overflow. All of these problems cause issues with floor integrity.

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When tiling a shower enclosure or another area that needs a waterproof surface, such as in kitchens or bathrooms, most tiling contractors use the two most popular brands of backer board: HardieBacker and WonderBoard.

These cement boards are a low-cost alternative to floating a floor or wall surface with plaster or render and are often used as a moisture-resistant foundation when tiling walls, floors, countertops, splashbacks, or other installation projects. 

Generally, you should thoroughly consider the two manufacturers’ product lines and decide which is the best for your purpose.

You can use both Hardie boards and WonderBoard products in similar settings. However, their different properties help them lean towards slightly different applications. 

Below, we give a helpful comparison table summarizing the similarities and differences between the two brands.

Hopefully, after reading this information, you’re more informed about Hardie board and WonderBoard products and can decide which one to choose for your situation.

HardieBackerWonderBoard Lite
Protects existing surfaces while giving a stable foundation for tiles.
Stable in use and resistant to environmental damage.
Board contains cement mix, cellulose fibers & MoldBlock additive.Board contains a cement mix and a fiberglass reinforcing mesh.
Needs unique specifications before use, such as waterproofing sealants, unlike WonderBoard panels.More straightforward to use compared to Hardie board.
Lightweight and more flexible than WonderBoard.Heavier and less flexible than Hardie board. However, can be used around curved surfaces.
Easy to cut the exact size required because of the lack of reinforcing mesh.Difficult to cut to the exact size, especially small areas, due to reinforcing mesh.
Cellulose fiber reinforcing reduces the board's durabilityFiberglass reinforcing increases durability.
Recommended for indoor use only.Recommended for indoor and outdoor use.
Regular boards are water-resistant only. The panels need additional waterproofing sealants.All boards are waterproof.
Recommended for low water exposure environments.Use in all environments, even high moisture areas.
Requires specific stud spacing distances when installing. Not always available.Because of reinforcing mesh, these boards don't require specific stud spacings.
More compatible with sensitive materials. For example, enamel and vinyl.Can damage enamel and vinyl surfaces. For example, bathtubs, shower trays, etc.
Equivalent products cost more than WonderBoard.Equivalent products cost less than Hardie board.
Better for smaller surfaces, such as plumbing enclosures, vanities, and corners, because less prone to breakages.Better for large surfaces such as unbroken walls and floors because it's less expensive and more durable. 
Less brittle than WonderBoard.Prone to snapping, especially when cut into narrow pieces.
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Backer Board Sizes

All backer boards come in standard sizes of 3 ft x 5 ft. These dimensions are slightly smaller than drywall boards, usually available in 4 ft x 8 ft sheets.

Backer boards also come in various thicknesses, as different applications require different thicknesses.

For example, kitchen splashbacks require quarter-inch thick backer board panels. In comparison, tiled flooring needs a minimum of a half-inch thick backer board overlaying at least a half-inch plywood subfloor thickness.

Furthermore, for tiling walls and ceilings, expect to use half-inch thick backer boards. In contrast, tiled countertops require at least a quarter-inch thick backer board over a minimum of quarter-inch exterior grade plywood.

Now, let’s move on and discuss these two brands in more detail.

What Is HardieBacker?

Photo: PunkToad / Flickr / CC BY 2.0

HardieBacker boards incorporate cellulose fibers within the Portland cement, which produces a much more lightweight panel than a traditional cement-only board.

Contractors use HardieBacker boards in indoor wet areas such as bathrooms, shower areas, and kitchens.

However, as the panels are only water-resistant, unlike WonderBoard, which is waterproof, it’s inadvisable to use them in areas of heavy water exposure such as the bathroom or wetroom walls and floors.

Instead, use them on counter splashbacks, kitchen floors, and ceilings, or when building vanity units and enclosing plumbing.

If you want to tile in heavy moisture environments, use a product such as a WonderBoard panel. Alternatively, HardieBacker supplies a waterproof product called the HydroDefense.

HardieBacker panels are backer boards made from a 90% Portland cement mix, with 10% reinforcing cellulose fibers and performance-enhancing anti-mold additives.

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Unlike gypsum drywall boards, they’re excellent at resisting moisture (but aren’t waterproof), give good tile adhesion, and incorporate MoldBlock additives to prevent mold growth and rot. 

Below is a video showing how to install HardieBacker panels:

What Is WonderBoard?

Photo: Ungaio / Flickr / CC BY NC ND 2.0

WonderBoard Lite is also a cement backing board but includes a fiberglass mesh reinforcement.

Like HardieBacker, its primary use is in wet areas as a backer board for tiling. However, unlike Hardie board, it’s completely waterproof and can be used outdoors and indoors.

Because of its components and manufacturing process, it doesn’t absorb moisture, so it is impervious to rot or mold growth. 

The panel’s fiberglass mesh reinforcement makes cutting challenging unless you own a circular saw. Also, it tends to crumble into small pieces, which may fall onto shower trays or bathtubs and scratch the surface.

Generally, WonderBoard is around $2 per panel cheaper than Hardie board, which isn’t a lot. But, over a large project, this difference can add up to a significant saving.

Here is a video showing the installation procedure for WonderBoard panels:

6 Differences Between HardieBacker And WonderBoard

Although Hardiebacker and WonderBoard panels have similar uses, there are several significant differences.

1. Composition

HardieBacker comprises a 90% Portland cement mix, 10% cellulose fiber, and performance-enhancing proprietary HardieBacker additives.

On the other hand, WonderBoard consists of a Portland cement mix with a reinforcing fiberglass mesh and the company’s proprietary additives.

2. Usage

Because WonderBoard uses fiberglass rather than cellulose as a reinforcing component, its products are better in wet areas than the regular HardieBacker products.

However, in addition to its many standard products, which are water-resistant rather than waterproof, HardieBacker also has a waterproof product range called HydroDefense.

Therefore, unlike waterproof WonderBoard products, regular Hardie board products need additional waterproofing sealants.

Because of this inherent difference between the two brands, all WonderBoard products are approved for interior and exterior use, while you should only use regular HardieBacker panels for indoor projects.

3. Working Alone

WonderBoard panels are heavy to carry, maneuver, and install compared to HardieBacker.

Therefore, unless you specifically require a completely waterproof backer board, use HardieBacker if you work alone.

4. Material Properties

Reinforced cement boards are more resistant to force than plywood and gypsum wall boards and are less likely to shrink. Therefore, they’re more robust and resist movement.

Furthermore, these backer boards can last up to 50 years with proper maintenance and protection. 

Generally, both boards are water resistant. But, because of the different construction materials, WonderBoard is classed as waterproof rather than water resistant.

In addition, the difference in materials also determines the difference in properties.

HardieBacker, made from cement, and cellulose fibers, is less robust than WonderBoard, made from cement and a fiberglass mesh.

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However, this difference also means HardieBacker boards are more flexible and lightweight than WonderBoard, thus allowing more manageable and more efficient installations.

5. Shaping to Fit

Because of the simple components of cement and cellulose in HardieBacker boards, they are easy to cut and shape and even more straightforward when following the pre-cut grid template.

On the other hand, WonderBoard products containing fiberglass mesh are harder to cut and shape easily. Furthermore, they’re more prone to uncontrolled breaking. So, the manufacturer suggests scoring using a sharp knife and breaking like drywall.

Alternatively, you can use a circular saw. But, this quickly blunts cutting blades and produces large volumes of cement dust, requiring goggles and a respirator.

6. The Price

Prices depend on the different stores you buy these products from, the thickness, and the product range you choose. However, generally, HardieBacker is more expensive than WonderBoard.

For example, suppose a 5 ft x 3 ft x 0.25 inch HardieBacker board costs around $13, and a WonderBoard product of the same size costs around $11, the difference is $2.

WonderBoard vs. HardieBacker Board: Similarities

Apart from the differences, WonderBoard and HardieBacker panels have some similarities too.

1. Materials

Both brands provide a cement-based backer board for protecting underlying surfaces while providing a stable foundation suitable for laying tiles.

2. Stability

Both brand panels are stable in use and won’t shrink or expand.

3. Moisture Resistance

Both product brands have moisture-resistant properties.

However, the WonderBoard panels are entirely waterproof, unlike the HardieBacker boards, which are merely water-resistant. But, HardieBacker panels contain MoldBlock additives to prevent mold and rot caused by seeping water.

4. Installation

You can install WonderBoard and HardieBacker products using similar methods.

When installed as walls, fit them onto studs using stainless steel screws. However, HardieBacker panels need specific intervals between studs.

When used as a tiled floor support, fix them to a plywood subfloor first.

Which One Should You Choose?

Although cement backer boards from these two companies are similar, it’s difficult to say which is better because their properties are different and target slightly different applications. 

A lightweight HardieBacker board is excellent for small indoor projects such as vanity surfaces and projects using small pieces and when the contractor works alone. Furthermore, this product is less prone to shattering when cut into narrow pieces. In contrast, a WonderBoard product is heavier, costs less for similar-sized boards, can be used indoors and outside, and provides a sturdy and stable foundation for medium to large areas of wall and floor tiles.

Therefore, consider the project and choose the best product for your application.