How to Install Tiles on a Cement Floor

Cement is the second most popular subfloor for tile installations behind plywood and the easiest of the two to install tile upon. Like any subfloor that you install tile on, the surface should be free of debris, level and sound. If the cement floor is not level you may need to pour a leveling compound, a thin, liquid cement, over the surface in order to level it out. If the subfloor had a previous installation on it, make sure that all adhesives and thinset are completely removed before the installation of a new surface. Before installing your tile, throughly sweep the surface with a broom or compressed air to completely remove any dust that may hinder adhesion of the new tile.

Things You'll Need

• Thinset
• 5-gallon bucket
• Grinder
• Grinder mixer attachment
• ½-inch trowel
• Wet saw
• Tile
• Tile spacers
• Grout
• Padded grout float
• Grout sponge

Instructions

Laying Out the Tile

1. Find the exact center of the room. To do this, find the center of each wall at the floor and draw a line to the opposite wall center. The intersection of the two lines will be the exact center of the room.

2. Lay a row of loose tiles from the center mark, along one of the center lines to one wall. Be sure to insert spacers between tiles so that you get a proper layout. You will most likely not be able to fit the last tile flush to the wall. This is fine--leave that one out.

3. Measure the distance from the wall to the last full tile. Mark down this distance and remember it for later.

4. Lay a row of loose tiles from the center mark along the center line to the opposite wall, and measure the distance from the wall to the last full tile.

5. Move the center mark and the other line running through it, in order to split the difference between the two measurements and properly center the line of tile. For example, if there were eight inches of space on the left side and four inches of space on the right side, you would adjust the center mark two inches to the left in order to leave six inches of space on each side.

6. Repeat this process with the other two walls to center the tile in that direction as well, and mark the new center at the intersection of your new adjusted center lines. This will leave the room in four quarters. You will tile the room one quarter at a time and start each section from the adjusted center mark.

Mixing the Thinset

1. Empty the bag of thinset into a 5-gallon bucket and add half the water recommended by the thinset manufacturer.

2. With the mixer attachment connected to your grinder, mix until the existing water and thinset are fully incorporated.

3. Gradually add the remaining recommended amount of water, in small amounts, to the thinset while continuing to mix it.

4. Allow the thinset to rest for 15 minutes so that the adhesives within it can fully activate.

Laying the Tile

1. Scoop some thinset out of your bucket with the ½-inch trowel and spread it across the corner of one of the quarters at your adjusted center mark. Keep the trowel at a 30-degree angle and spread the thinset in large half-arc strokes. The thickness of the laid thinset should be as uniform as possible, no more than 1/2-inch thick, and should accommodate one of your tiles with only several inches of excess thinset on each side.

2. Place the first tile on the thinset at the center mark and give the tile a gentle, even press so that it bonds to the thinset. Check the tile with a level if necessary by laying the level diagonally across the tile from corner to corner.

3. Spread more thinset for another tile next to the first one, insert the tile and insert two tile spacers between the tiles. Place the tile close enough to the first one that you do not have to shift it excessively to be flush against the spacers.

4. Continue this process of spreading small patches of thinset, setting tiles and inserting spacers. Work in whatever direction is appropriate for the room so that you do not trap yourself in a corner. Thinset will begin to harden after about 20 minutes, but you do not want to actually walk on the tile for several days.

5. Cut tiles that will butt against the wall or other obstructions with the wet saw. Remember when measuring these spaces to account for the distance that your joint (and spacers) will occupy in the area.

6. Continue around the room, completing it in the quarters marked out by your center line marks. When finished, allow the tile to set according to the thinset manufacturer's instructions before walking on it. This is typically 48 hours but may be shorter or longer depending on the thinset.

Grouting the Floor

1. Mix the grout according to the manufacturer's instructions.

2. Scoop up a cup-sized portion of grout with the padded grout float.

3. Spread the grout in a diagonal direction to the tile joint. Keep the float at a 30-degree angle and be wary of gaps in your coverage.

4. With a wet grout sponge, wipe up any excess grout in a diagonal direction to the joint. Rinse the sponge often, and make sure you adequately remove any grout on the tile surface.

5. Wipe the grout sponge along the joints to recess and shape the grout within the joints.

6. Allow the grout to set for the manufacturer's recommended amount of time before walking on the floor.

Tips & Warnings

• Natural stone should be sealed prior to grouting to prevent the dyes in the grout from staining the tiles.

• When installing natural stone and tiles that are printed with variations, select tiles randomly from all the boxes to minimize the appearance of any inherent variations that are present in the different lots of tile.

References

• Installing Floor Tile
• How to Lay Tile