How to Tile Over Cracks

Concrete makes an ideal surface for laying tile--as long as it is in good shape. In addition to evening out bumps and divots, it's necessary to fill in any cracks in the concrete before laying tile. Filling cracks helps ensure a level surface, necessary for a successful tile job. Plan on devoting a weekend to tiling over concrete, especially if you have to fill in cracks.

Things You'll Need

• Broom
• Wire brush
• Chisel
• Vinyl concrete patching compound
• Trowel
• Mortar
• Plastic spacers
• Grout
• Rubber float
• Sponge

Instructions

1. Remove the debris and dirt around the crack, using a broom and a wire brush. If the crack is wide enough to fit the end of a small edge chisel or sledgehammer, insert the tool into the crack and use it to undercut the edges of the crack. Undercutting means making the crack slightly wider just beneath the surface. Clean away debris again after undercutting.

2. Mix vinyl concrete patching compound per the manufacturer's instructions. Apply the compound over and into the crack, using a trowel. Smooth the surface of the crack with the trowel. Wait the recommended dry time.

3. Smooth out the surface with a brush to match the surrounding concrete and create a level surface.

4. Mix thinset mortar in a 5-gallon bucket; only mix as much as you can lay in 15 to 20 minutes. Apply mortar to the concrete with a notched trowel designed for laying mortar.

5. Press a tile into place. Apply plastic spacers to each corner of the tile, and place the next tile. Continue the process around the room. Cut perimeter tiles with a scoring cutter or wet saw. Allow the mortar to set per the manufacturer's instructions.

6. Mix the tile grout in a 5-gallon bucket, using a mixing paddle. Apply the grout with a rubber float, pressing it in between the tiles while holding the float at a 45-degree angle.

7. Wipe off excess grout with a wet sponge.

Tips & Warnings

• You can start laying tile in the center of the room, or along the most visible walls so that the only cuts are less conspicuous.

References

• Danny Lipford: How to Lay a Tile Floor
• Lowe's: Make Simple Concrete Repairs