How to Prep Concrete Floors to Tile

Before tiling over concrete, it is necessary to prepare the floor surface to allow for the best possible bonding of the tile to the concrete. Before beginning the tile process, you must first empty the floor, clean away any chemicals or substances that would interfere with the tile adhesive, and fill any cracks or depressions. Prepping materials are available at most hardware and home improvement stores, and the process takes only about a day.

Things You'll Need

• Broom
• Scrub brush
• Dish washing soap
• Bucket
• Concrete patching compound
• Putty knife
• Floor leveling compound
• 4-by-8 concrete backer boards
• Circular saw
• Flooring adhesive
• Paint roller
• Workshop vacuum

Instructions

1. Remove any items, furniture or other objects from the room. Sweep and dispose of any loose debris, dust, hair or other materials covering the concrete floor. You want the floor as neat as possible before continuing.

2. Use a scrub brush and a mild liquid dishwashing soap solution in a bucket to clean the floor completely. This will help to remove any oil, wax or grease from the floor and make it easier for tile adhesive to bond with the concrete. Rinse the floor with water to remove the soap and allow the floor to dry completely.

3. Examine the condition of the concrete to see if it is acceptable for laying tile. There should be no significant cracks across the floor. Ignore hairline cracks, but fill large cracks with concrete patching compound. Use a putty knife held at a 45-degree angle to force the material down into the crack. Smooth and feather it across the surrounding floor. Allow the compound to dry overnight before continuing.

4. For uneven or depressed areas, use the putty knife to spread a floor leveling compound over areas that need evening out. This thick liquid spreads evenly across low areas and raises them in line with the rest of the floor area. For significant floor damage or imbalance, consider laying 4-by-8 sheets of concrete backer board over the floor. Trim the boards with a circular saw to fit as needed. These boards require an adhesive brushed or rolled over the floor to help fit them securely.

5. Use a workshop vacuum to clean up any debris or dust from the prep work on the floor. You want the floor to be free of anything that will get in the way of the tile adhesive or would keep the tiles from lying flat.

Tips & Warnings

• Allow for proper ventilation when working with the patching compound to help reduce odors.

• Wear safety goggles and a face mask when cutting backer boards or cleaning a dirty concrete floor.

References

• “Smart Guide: Ceramic Tile, All New 2nd Edition: Step by Step;” Editors of Creative Homeowner; 2009