How to Install Ceramic Tile Underlayment

  • 6-10 hours
  • Beginner
  • 250-500
What You'll Need
Mesh drywall tape
Galvanized drywall screws (1 1/2 -inch)
Screw gun
Mortar trowel with notches along one side
Thinset mortar
1/2 -inch cement board for enough sheets to cover the floor

Installing a ceramic tile underlayment is essential because the ceramic tile floors are stiff and somewhat fragile if not properly positioned. An underlayment provides a sturdier base foundation, preventing cracks in the tiles. Underlayment refers to the layer sandwiched between your wood subfloor and your ceramic tiles. Follow the instructions below to make an inexpensive yet strong underlayment.

Step 1 - Mark the Cement Board

In the corner of the floor, lay down the first sheet of cement board and using a pencil mark its edges. This marking will be used as a guide for the next step. You may remove the cement board and proceed to the next step which is to spread thinset mortar on the area to be covered. Use the mortar trowel with the notches along one sire to scrape the on the area and put lines in it.

Step 2 - Screw the Cement Board

Place the cement board back and using the screw gun and galvanized drywall screws fasten it down. Let the screws sink right through the cement board every 6 to 10 inches, and make sure that you bury the screws' heads just below the surface. Repeat steps 1 and 2 for the next board cement sheets, spread it out by rows and make sure that there are no 4-way intersections. Use the jigsaw to cut the ends of the boards.

Step 3 - Finish the Underlayment

To finish this ceramic tile underlayment process, apply mesh drywall on the joints of each cement board sheets. Using the flat side of the trowel, proceed to apply thinset mortar over the taped joints and leave it for a day. Once you come back, the ceramic tile underlayment is completed and can now be filled with ceramic tiles.