Can You Put Ceramic Floor Tiles Over Plywood?

Laying a ceramic tile floor often requires special cutting tools because the tile is so hard. However, the actual installation process is not difficult, according to the University of Minnesota guide to affordable green housing. Builders and homeowners often choose ceramic floor tiles for use in entry halls, kitchens and bathrooms because it provides a durable walking surface and it resists water.


Ceramic floor tile can cost from $5 to 15 per square foot installed, as of July 2011, according to the University of Minnesota. That puts it at the high end of flooring when compared to other materials such as linoleum, vinyl, cork, carpet, laminate and hardwood flooring. However, ceramic tile flooring can last from 25 to 100 years, although hardwood, which ranges from $6 to $12 per square foot, can last that long too.

Plywood Underlayment

Although you can put ceramic floor tiles over plywood, flooring experts say you must be careful. If the plywood under the tile flexes, the ceramic tile will crack or the grout between the tiles might pop out. As long as the span between the floor joists is no more than 16 feet, 9 inches and the joists are No. 1 grade, you can use plywood as an underlayment with ceramic floor tiles. Use 3/8-inch exterior grade plywood placed over a subfloor of 3/4-inch plywood, with the latter securely attached to the floor joists, according to Tim Carter of Ask the Builder. Because plywood expands with humidity, place the 3/8-inch plywood on top of the 3/4-inch plywood with a 2-inch offset at the edges and leave 1/8 inch of spacing around each sheet of plywood; otherwise it might expand, buckle and crack the tile.

Other Underlayment

Carter also says that cementitious board makes a good underlayment for ceramic floor tiles. According to , the most important part of installing ceramic floor tile is using a strong and sturdy underlayment, so it recommends using concrete backerboard, also called cementitious board. Backerboard has a solid concrete core sandwiched between fiberglass and cannot be damaged by water.

Cleaning Ceramic Tile

You can use a commercial ceramic tile cleaning product to wash the floor, or use 1/4 cup of low-suds detergent in a gallon of water or mix 1 to 2 tbsp. of trisodium phosphate or washing soda in a gallon of hot water. Use the solution to mop the floor, or use an electric floor scrubber and rinse. However, the grout can become dirty or discolored. When that happens, apply a mixture of chlorine bleach and water. Let it soak for 20 to 30 minutes, and wash the floor as usual. Apply wax after the floor has dried.

By master