Do You Have To Put Down Cement Board Under Tile

Do You Have to Put Down Cement Board Under Tile?

Installing tile is a popular choice for flooring in kitchens, bathrooms, and other areas, as it is durable, easy to clean, and available in a wide range of styles. In order to properly lay tile, it is essential to prepare the floor with the appropriate substrate. Cement board is a popular option for this purpose, but is it really necessary to use it under tile?

What is Cement Board?

Cement board is a type of backer board specifically designed for use as a substrate for tile installations. It is made from a mixture of Portland cement, silica sand, and cellulose fibers, and is typically sold in sheets that are 1/4 inch to 1/2 inch thick. Cement board is water-resistant, dimensionally stable, and provides a strong and durable base for tile.

Why Use Cement Board Under Tile?

There are several benefits to using cement board under tile:

Moisture resistance: Cement board is highly water-resistant, which is essential in areas like bathrooms and kitchens where moisture is present. It will not absorb water or swell, and can withstand the moisture from spills, leaks, and high humidity.
Strength: Cement board is extremely strong and durable, making it an ideal substrate for tile installations. It can support the weight of the tile, mortar, and foot traffic without cracking or flexing.
Stability: Cement board is dimensionally stable, meaning it will not expand or contract with changes in temperature or moisture. This prevents the tile from buckling or warping.
Adhesion: Cement board has a slightly rough surface that provides excellent adhesion for thinset mortar. This ensures that the tile will adhere securely to the board.

When is Cement Board Not Required?

While cement board is generally recommended for most tile installations, there are certain situations where it may not be necessary:

Existing concrete or cement floors: If the existing flooring is made of concrete or cement, it may not be necessary to install cement board. These surfaces are already moisture-resistant and can provide a suitable base for tile.
Dry areas: In areas where moisture is not a concern, such as a living room or hallway, it may be possible to install tile directly over existing subflooring, such as plywood or OSB (oriented strand board).

Conclusion

Whether or not to use cement board under tile depends on the specific installation and the moisture levels in the area. In general, cement board is a highly recommended substrate for tile installations, as it provides moisture resistance, strength, stability, and excellent adhesion. However, in certain cases, it may not be necessary to use cement board, such as when installing tile over existing concrete or cement floors or in dry areas.