Do You Need to Prepare Concrete Before Tiling It?

Ceramic Tile

• The concrete base for your ceramic tiles must be level, clean and free of paint or stains. Tile adheres to concrete with an adhesive or a mortar. Do-it-yourself practitioners get the best results by applying a thinset adhesive rather than setting the tile in a thick mortar. Thinset needs a smooth surface, free from dirt or additives that interfere with the chemical bonding process. Thinset cannot alter the contours of the underlying concrete. You must improve the quality of the concrete slab to avoid transferring the concrete's imperfections to the ceramic tile layer.

Vinyl Tile

• Self-stick vinyl tiles rely on an adhesive as well, but the manufacturer applies the adhesive, and the installer only needs to remove the protective paper backing to apply it. The quality of the finished product depends on how well the adhesive sticks to the concrete. Anything that comes between the adhesive and the concrete will leave the tile vulnerable to breaking, cracking or sliding out of place. Vinyl tiles will mimic the hills and valleys of the underlying surface and, therefore, you must level the concrete before applying vinyl tiles.

Existing Slabs

• Inspect your existing concrete slab and identify problem areas, in particular, cracks, high spots and depressions. Repair these areas by first cleaning the floor thoroughly. Remove paint, wax and sealers. Fill cracks, add leveling compound to depressions and grind down high spots before applying either ceramic or vinyl tiles.

New Slabs

• Pouring a new concrete slab gives you an opportunity to introduce elements that may help reduce the frequency and severity of cracks in the concrete leading to a more suitable surface for your tiles. All concrete is subject to cracking, but builder Tim Carter recommends adding steel and fibers to the slab to help hold the concrete together and keep the size of cracks small and relatively harmless.