How to Lay Tile & Repair Concrete Cracks in the Floor

Flooring tile

When you plan to install tile on a concrete floor, any cracks that are in the concrete must be repaired. Cracks create areas of sub flooring that are not level and cause weak points. Sub floors that are not level or have large cracks will create weak or raised areas in the tile. The cracks in a concrete sub floor are repaired with a ready mix concrete patch before the installation of the tile.

Things You'll Need

• 2, 5-gallon buckets
• Concrete trowel
• Ready mix concrete patch
• Tape measure
• Pencil
• Chalk line
• Straight edge
• Spacers
• Wet saw
• Variable speed drill
• Mixer bit
• Thin set
• Tile trowel
• Grout
• Float
• Sponge

Instructions

Sub Floor Crack Repairs

1. Pour a 1/4 bag of concrete patch into a 5-gallon bucket. Slowly add water to the concrete mix and use a variable speed drill and mixer bit to blend the concrete patch and water. Hold the bucket tightly between both feet when you are mixing the concrete patch, or the bucket will spin and throw concrete patch everywhere. The final mix should be no thicker than a brownie mix.

2. Spread an even coat of concrete patch over all cracks. Smooth the concrete patch with the trowel so that it is level with the surrounding floor area. Mix more concrete patch as needed.

3. Allow the concrete patch to dry before installing the tile flooring.

TIle Installation

1. Measure to find the center point of the north wall in the room that you will install the tile in. Make a pencil mark on the sub floor. Find the center point of the south wall, or the wall directly across from the first wall you measured. Mark the center location on the floor.

2. Ask a helper to assist you with stretching a chalk line tightly across the floor on the center pencil marks you made. Lift the chalk line and let it snap back down. The chalk will create a line across the floor. Repeat each step on the east and west side of the room. The sub floor will be divided into four separate squares.

3. Add approximately 2 inches of water into the bottom of a 5-gallon water. Pour 1/4 bag of thinset into the bucket. Mix the thinset and water with a variable speed drill and drill bit. Add water and thinset to the bucket until you have mixed 1/2 of the bag. Allow the thinset to sit in the bucket according to the manufacturer’s recommended amount of time. This is usually 10 to 15 minutes. The thinset mixture should resemble the consistency of pudding.

4. Use the tile trowel to spread thinset on the back of four tiles. Set each tile in the center of the room where the chalk lines meet. There should be four tiles creating a square. Place spacers in between each tile to evenly space them apart. Starting a tile installation in the center of the room will create even sized cut tiles when you reach the outer perimeter of the room.

5. Continue laying two tiles at a time from the center tiles until you reach a wall that is away from the main entrance to the room. The last tile will need to be cut with the wet saw. Finish laying the next to the last row of tile from wall to wall before you complete the cut row against the wall. Start laying each new row of tile beginning with the center tile, and work your way across and out of the room. Allow the tile to sit overnight before grouting it.

Grout

1. Remove all of the spacers from the grout lines. Mix a 1/2 bag of sanded floor tile grout. Add 2 inches of water to the bottom of a bucket. Add grout to the water and mix the solution with a variable speed drill and mixer bit. Add more water to the mixture if the grout is too dry. The grout mixture should be the consistency of a brownie mix. Fill a second 5-gallon bucket with clean water.

2. Spread grout across the grout lines in a 3-foot by 3-foot area with a grout float. Hold the grout at a 45- degree angle when you spread the grout. The position of the float will fill the grout lines, and drag excess grout off the lines.

3. Dip a tile sponge into the clean water and wring it out. Place the sponge flat on the grout lines and pull the sponge towards you. Do not apply excessive pressure to the grout lines. The sponge is used to smooth the grout lines. Rinse the sponge and use the edge to carefully wash the tile around the grout lines.

4. Continue grouting and washing the tile until all the grout lines have been filled. Allow the grout to dry overnight and wash the entire floor.

References

• 5 Minute Videopedia: "How to Prepare a Concrete Subfloor for Flooring Installation"
• Handyman Fix Home Repair: "How to Lay a Tile Floor"
• Construction Videos: "How to Lay Tile