How to Install a Backer Board

  • 2-4 hours
  • Beginner
  • 250-500
What You'll Need
Backer board
Tape measure

Installing backer board is a critical part of the tile installation process when you are not working with a concrete subfloor. The backer board is necessary to support the tile when you are installing it on top of wood. If you do not use backer board, the tile will tend to break when you start walking on it. Here are the basics of how to successfully install backer board.

Step 1 - Estimate

The first thing that you should do is estimate how much backer board you are going to need. You need to take your tape measure and get the length and the width of the room. Multiply the 2 numbers together to get the square footage. Most backer board comes in 3x5-foot sheets. This means that each sheet will cover 15 square feet. Therefore, you need to take the square footage of the room and divide it by 15. Round up to the nearest whole number to tell you how many sheets you need to buy. You might buy an extra sheet just in case you have a lot of waste.

Step 2 - Prepare

Before you can install the backer board, you need to make sure that the room is ready. You need to remove any flooring that is currently on the floor. Remove the baseboards from the wall as well. When you get down to a wood subfloor, you are ready to proceed.

Step 3 - Spread Adhesive

Start out by spreading some of the thinset adhesive to the floor where you are going to put the first board. Take your trowel and use it to evenly spread some of the thinset on the floor. Try not to get too much thinset out at one time. Then press the backer board down into the adhesive. The backer board should have thinset underneath all of it.

Step 4 - Adhere

Once you have laid the backer board down into the adhesive, you need to attach it to the subfloor. You can do this in one of two ways. You can either nail it or screw it down. Use your hammer and nails or drill and screws to attach it to the wood subfloor. You will notice that there are several holes in the backer board. Make sure that each one of these is filled with a nail or a screw. This is necessary so that there will been absolutely no movement in the backer board when someone steps on the tile.

Step 5 - Cutting

When you get to an area that an entire sheet will not fit, you are going to have to cut it. Use your saw to cut the backer board to fit.

Step 6 - Tape

When you get all of the backer board down on the floor, you are going to need to cover up the seams where the boards meet. Use a fiberglass tape to cover them up.