Cement Board Vs DITRA: Detailed Comparison (Choose This!)


Cement board and DITRA are two common plywood or drywall substitutes typically used for wet applications. However, they are very different from one another. 

When it comes to tiling your mudroom or bathroom, which one should you choose?

Cement board is a moisture-resistant alternative to drywall and plywood. It doesn’t deteriorate or harbor mold, but it isn’t fully waterproof. Installation is typically done with modified thinset and screws. DITRA is a fully waterproof uncoupling membrane designed to provide flexible support for your tile. It is more expensive than cement board, but it enhances protection against cracks.

What Is A Cement Board? 

Cement board is a mixture of cement, fiberglass, limestone powder, water, and silica formed into sheets. 

Appearance-wise, it is similar to drywall. However, cement board – or backer board – offers higher moisture resistance and is a better choice for wet applications.

This material often replaces drywall in shower stalls. It is also used as a substrate in all rooms that require a level surface for tile floor installation, including bathrooms and mudrooms. 

However, cement board is heavier than drywall and could be challenging to install vertically or on subfloors that can’t bear a heavy load. 


What Is DITRA?

DITRA is an uncoupling plastic material specifically designed for the installation of stone or porcelain tile on any even and load-bearing substrate. 

This flexible sheet is fully waterproof and features an open rib structure that neutralizes differential stress movements of the tile.

In this way, it reduces the risk of cracks while also being suitable to use in interior and exterior applications. 

DITRA can be used for both wall and floor coverings, and it can be installed over drywall, plywood, or even cement board.


Cement Board Vs DITRA: 7 Key Differences 

DITRA and cement board are both used instead of drywall in the shower or other wet applications, but how do they compare?

The table below shows a quick overview of these construction essentials: 

CharacteristicsCement BoardDITRA
InstallationMore challengingLess challenging 
ApplicationWalls and floors; less ideal in wet areasWalls and floors; more ideal in wet areas
Mortar typeModified thinset Modified or unmodified thinset
Water resistanceResistantWaterproof 
Rigidity RigidFlexible 
Thickness1/4-inch1/8-inch
Price Cheaper More expensive

1. Installation

Cement board and DITRA are both easy to install, but cement board requires extra steps and, often, an extra set of hands. 

Typically, cement boards are fixed with a thin layer of thinset mortar to the plywood. However, this substrate isn’t waterproof, and you may want to apply a waterproof membrane between these boards and the wooden material. 

Backer boards must also be fastened to the plywood with screws right after installation while the thinset is still fresh.

When installing cement boards on walls, the sheets are screwed directly onto the studs. A waterproof membrane should be installed first in high moisture areas, such as shower stalls. 

Due to the cement’s weight, you might want to ask a helper to keep the boards in place as you’re fastening them to the studs.

DITRA has a more straightforward installation. 

This flexible substrate is lighter than backer boards and easier to install on walls without help. However, because DITRA can only be installed on even support, you would have to install drywall (or backer boards) first. 

Floor installation is much more seamless. This substrate can be installed with unmodified thinset on concrete or cement subfloors. Modified thinset is required for plywood.  

2. Application

A major difference between DITRA and backer boards is that the former is fully waterproof, whereas the latter is only water resistant. 

Sure, cement board doesn’t deteriorate when it becomes soaked, and it typically doesn’t harbor mold. 

Yet, the dampness can pass through the cement and infiltrate the substrate under or behind it, such as the plywood subfloor or wood wall studs.

If these materials remain damp for too long, they can harbor mold and even rot, potentially affecting the structural integrity of your home.

For these reasons, cement boards are usually recommended for tile installation in high-traffic but not high moisture areas.

When installed in high moisture areas, you should use them with a waterproof membrane or opt for waterproof cement boards, which are more expensive. 

DITRA, as mentioned, is fully waterproof. It can also bear heavy loads when installed on flat, even surfaces. Thus, DITRA is suitable for all kinds of indoor and outdoor applications.

3. Mortar Type

Choosing the right type of mortar is crucial when installing any kind of substrate. 

In the case of cement board and DITRA, the former requires modified thinset regardless of the substrate.

This happens because backer boards are not flexible, so they require a more flexible adhesive to prevent cracking during the normal expansion and shrinkage of the boards. 

DITRA is a flexible material and doesn’t need modified thinset on most substrates. In fact, unmodified mortar can be used on all substrates except for plywood. 

The only reason plywood requires modified thinset is the lower moisture concentration in the adhesive, which speeds up drying time and prevents the plywood from getting too damp.

4. Water Resistance

As we already mentioned, DITRA is fully waterproof, whereas cement board is not. This is why cement boards require a waterproof membrane for damp applications.

DITRA doesn’t require any additional materials, cutting off costs.

5. Rigidity 

Installing tiles on a rigid substrate may seem like a good idea, but it isn’t. Stone or porcelain tiles aren’t flexible, so any differential movement stress could crack them if installed on a rigid surface. 

As asserted, cement boards are rigid. For this reason, you should always leave a space between the boards when installing them to ensure enough room for expansion. Even so, your tiles might still crack. 

DITRA is an uncoupling membrane, which basically means that it allows for in-plane movement. This feature neutralizes the differential movement stress and lowers the chances of your tiles cracking.  

6. Thickness

Another advantage of DITRA is the minimal thickness it adds to the substrate. 

These sheets are 1/8 of an inch thick. Cement boards used in residential applications are 1/4 of an inch thick, but thicker boards (half an inch) also exist.

On top of this, you must account for the thickness added by the adhesive. 

Maintaining additional bulk to a minimum is often important, especially if you’re replacing the floors and don’t want to cut the doors to fit them in. 

7. Price

One point in favor of cement boards is the price. 

Depending on the type, a 5×3 ft. panel can cost between $9.98 and $21.40 on average – or between $0.66 and $1.42 per square foot, labor and mortar excluded. 

A standard DITRA roll (53.3 by 3.3 ft.) costs around $413, which turns out at $2.35 per square foot – labor and mortar excluded. 

However, considering that cement boards might require a waterproof membrane, too, and that they need modified mortar, which is more expensive, installing DITRA could actually be more cost-effective. 


Summary

Cement board and DITRA are two substrate options for stone and porcelain tile installations in high moisture areas. 

DITRA is fully waterproof, and it can be installed on any even surface, including concrete and plywood. Cement board is typically installed over plywood. When installed on walls, cement boards can be fastened directly to the studs, but DITRA requires a solid background, such as drywall or concrete.

However, the cement board is only water resistant and could let water seep into the wooden substrate. This is why you might have to install a waterproof membrane.

Both cement board and DITRA are installed with thinset, but you can use unmodified mortar with DITRA (depending on substrate). DITRA is more expensive upfront, but installing cement boards could be more time-consuming and expensive when adding up the additional labor and materials.

Roxana Bikfalvi

Roxana is a copywriter passionate about home improvement and interior design. When she’s not writing, you can find her upcycling old furniture or remodeling interiors. She has written for numerous home improvement blogs before joining PlumbJoe.

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