How to Prep a Floor for Ceramic Tile

Ceramic tile flooring is available in a large array of colors and designs.

The most important aspect regarding the installation of ceramic tile is that it has a level surface to adhere to. Unlevel surfaces put extra stress on the sides of each tile and eventually cause them to crack and break. Concrete surfaces may shift in the future as a home settles, so it is critical to start with a level and smooth surface in this application. All surfaces, including concrete, wood and tile must be clean, dust free and level to start the installation of ceramic tile.

Things You'll Need

• Fast drying thinset mortar
• Trowel
• Sponge mop
• 4-foot level
• Marking pen
• Electric sander
• Vacuum

Instructions

Concrete Floors

1. Fill all cracks and crevices with fast drying thinset mortar to produce a level floor without blemishes. Use a trowel to fill the cracks, dips and crevices with a heavy application to bring them to the surface level. Let the mortar dry for about 10 minutes.

2. Apply thinset mortar to the entire concrete floor with a sponge mop to smooth the surface. Let the mortar dry for about 10 minutes.

3. Examine the entire surface with a 4-foot level by starting at one corner and working towards an adjacent corner. Move the level down, and work back and forth from side to side to check the level of the entire floor. If there are any unlevel spots, mark them with a marking pen, and reapply thinset mortar with the trowel to fill them in as needed.

4. Clean the entire floor with a mop and water to make sure that the tile will adhere. Let the floor dry completely before installing ceramic tile.

Wood Floors

1. Sand plywood floors before the application of ceramic tile so the tile will stick. Use an electric sander to smooth the surface. An electric sander with a dust collector will save a step in this process.

2. Empty the dust collector as it becomes full. Electric sanders without a dust collector require you to vacuum the floor after sanding to remove debris.

3. Feel the surface of the floor. The entire surface should feel smooth to the touch if it has been adequately sanded.

Tile Floors

1. Use an electric sander to sand the entire surface of a tile floor to rough up the existing tile so the ceramic tile will stick to the old floor. This is often an easier application than trying to pry up old tile from the floor, resulting in an uneven surface to start the process.

2. Apply an application of thinset mortar to the old flooring with a sponge mop to create a smooth surface. Apply a heavier application in the crevices between the tiles to level the floor.

3. Let the thinset mortar dry for 10 minutes, and mop the floor to remove any debris. Let the floor dry completely before installing ceramic tile.

Tips & Warnings

• Concrete flooring is the most likely type of flooring to crack or break. It is important to level the floor before applying ceramic tile to concrete floors.

• When laying a ceramic tile floor over wood, check the floor for any soft or rotting spots in the floor. These areas require replacement so that they do not crack or break the tiles in a short period.

References

• Ceramic Tile Floor: Preparing The Subfloor For Tile Installation