How to Prepare a Floor to Install Porcelain Tile

person's hand on a porcelain tile
  • 2-10 hours
  • Intermediate
  • 0-250
What You'll Need
Cement Backer Board
Thinset Mortar
Notched Trowel
Seam Tape for Cement Backer Boards
Utility Knife
Tape Measure
Patch and Leveler
Roofing Nails or Screws

Before preparing to install porcelain tile in the floor of a kitchen, living room, bathroom, or bedroom, make sure to have a subfloor that is in good condition. Porcelain tile can be a good substitute to other types of ceramic tiles, but when you install porcelain tile, like any other ceramic tile, be sure to work on a level subfloor. Here are the instructions for how to achieve that goal.

Step 1 - Prep the Subfloor

Check if the subfloor is ready for the installation of the backer boards by using a level to check for surface uniformity. If some portions of the subfloor are lower than the others, make it level by applying a patch. Apply the patch according to the manufacturer’s instructions and allow it to dry before checking again with a level. If there are baseboards or trim at the sides of the floor, remove them first and reinstall them after the backer boards and the tiles are all set.

Step 2 - Prep the Cement Backer Boards

spreading thinset

Do not install porcelain tile directly to the subfloor unless it is already made of cement that has been made accurately level. Install cement backer boards first if the subfloor is made of other materials. First, measure the entire area to be tiled and use that measurement to determine how many backer boards are needed for the job. Purchase additional backer boards just in case (about ten percent of the estimated number of backer boards required). Cement backer boards are very useful because they provide a sturdy and stable foundation for the tiles.

Step 3 - Install the Cement Backer Boards

Prepare the thinset according to the manufacturer’s instructions and mix it well in a container. Scoop out a good amount of the mixture and transfer it to the notched trowel. Start working on the corners for easier installation. Begin the application of the mortar on a small portion of the floor enough to cover the area of one cement backer board. Make sure the thinset is applied evenly to ensure the backer boards will be installed uniformly.

Place one piece of backer board on top of the thinset mortar. Be sure to have its edges touch the walls. Press firmly until it is all set. Drill the screws on all four sides to secure it to the subfloor. Proceed with the other backer boards by following the same procedure. For the final pieces, measure the required dimensions and transfer the measurements on the boards. Cut them using a utility knife and install them in the same manner.

Step 4 - Finishing Touches

When everything is all set, cover the butt joints with seam tape. Cover the seam tapes with thinset mortar as well and allow it to dry. When the foundation is ready, install porcelain tile.