Can You Put Tile Right Onto Concrete?

Tile Properties

• Tiles vary in appearance, wear, cost and ease of care; but a common feature among most tile types is that they are rigid. Another similarity is that they have flat backs. Homeowners choose from among different materials for their tile floors, including ceramic, stone and porcelain. Typically, tiles are square or rectangles, but you may cut tiles into any shape.

Tile Adhesive

• Tile installers use adhesive to bond the back of each tile to the subfloor. The chemical properties of the adhesive as well as the composition of the subfloor dictate how well the tiles will stick to the subfloor. Thinset mortar, a popular adhesive, blends cement with finely graded sand and water to create a compound that you can spread over the subfloor at a depth of less than 1/2 inch. Variations and movements in the subfloor transfer to the tiles, and defects in the subfloor will increase the chance that the tiles will break.

Concrete Condition

• You cannot lay tile directly over concrete that is broken or covered with paint or dirt. Clean concrete to remove imperfections that will hamper the bonding process with the tile adhesive. Repair cracks and fill depressions and holes. Use a leveling compound to create an even surface across the full area where you are laying tile. Smooth high spots down with a grinder. Sand the polished concrete floors to abrade the surface so the tile adhesive has something to adhere to.

Alternative

• In some instances, you may decide that it costs too much money and takes too much time to try to bring your concrete slab to a condition where it is suitable for tiling. You do not have to give up on tile floors, and you do not have to rip out the concrete slab. Install an isolation membrane between the tile and concrete to reduce the chance that cracks and imperfections in the concrete will work their way up to the tile and cause the tile to break. Membranes are available as a thin fabric or a paintlike substance.