How to Prepare Concrete for a Tile Installation

Think you need to install a layer of plywood or a cement board underlayment over your concrete floor before laying tile? Before you do all the extra work, discover how easy it is to lay tile on concrete. Find out which precautions you should take before placing tile and find out how to prepare your concrete floor for laying tile. remembering that different types of floor tiles have different handling and installation requirements.

What You Need to Know Before Laying Tile on Concrete

Although you don’t need to install an underlayment between the concrete and the tile, you need to prepare the surface before placing the tile. After all, cracks and uneven areas in the concrete can cause damage to the tile above, and uncontrolled moisture in the concrete can destroy the mortar and loosen the tiles. When you take time to prepare the concrete floor, you’ll have a better chance of creating an even tile design that looks great and is built to last. Take a look at the two most common options for preparing a concrete floor.

Install Tile Directly on the Concrete Floor

In many cases, you can lay tile directly on the concrete surface, which is naturally hard and durable. This option works best when the concrete floor is in good condition, so take care to follow all of the steps below to repair cracks, fill depressions, and make sure the floor is level. Large ceramic flooring tiles will crack under heavy load if laid on an uneven floor.

Install an Uncoupling Membrane Between Concrete and Tile

Even though your concrete floor is in great condition now, it won’t always look that way. Concrete floors can easily develop cracks when the underlying foundation shifts and almost every foundation will experience at least minor shifts over time. You can anticipate that your concrete floor will eventually crack.

To prevent those movements from transferring to the tile floor, consider installing an uncoupling membrane between the concrete and tile surfaces. This flexible polyethylene layer is easy to install and can protect the tile from both cracking and moisture.

How to Prepare a Concrete Floor for Tile

After getting to know the precautions you should take before laying tile and choosing the installation option that works best for your floor, you’re ready to get started. Follow the seven steps below to get your concrete floor in great shape.

1. Gather Your Supplies

Before you get to work, take the time to gather the supplies and tools you’ll need. You’ll want to have the following at your fingertips:

• Box fan (optional)
• Broom
• Concrete patching compound
• Concrete sealer
• Degreasing cleaner
• Dustpan
• Five-gallon bucket
• Roller with extended handle
• Scrub brush
• Towels or cloths
• Trowel
• Uncoupling membrane (optional)

2. Sweep the Floor

No matter how dirty or clean the concrete floor looks, start the process by sweeping the floor. Use the broom and dustpan to give the entire surface a thorough sweep, and make sure you’ve removed all accumulated dirt, dust, and debris.

3. Scrub the Floor

After sweeping, give the floor a good scrub to remove any stubborn dirt or persistent stains. Pour a few tablespoons of degreasing cleaner into the bucket, and add about a gallon of warm water to create a cleaning solution. Use the solution and the scrub brush to clean the floor thoroughly. While you won’t want to miss any spots, you should spend extra time scrubbing greasy or oily areas.

Not sure which degreasing cleaners work best? Opt for standard dishwashing soap or a mixture with trisodium phosphate.

4. Rinse the Floor

Once you’ve scrubbed the floor, rinse it with warm water. Focus on one isolated section at a time, and use towels or cloths to dry each section as you go.

Since you’ll need the floor to be completely dry before moving on to the next step, allow up to a day for the floor to dry. If the humidity level is relatively high or if the area doesn’t receive much natural circulation, use a box fan to increase circulation and dry the floor faster.

5. Patch Any Cracks

After cleaning the floor thoroughly, you’ll need to patch cracks in the concrete floor, as they can expand and cause the tiles above to shift or break. Use a trowel to apply the concrete patching compound at the site of each crack.

Although you should fill the cracks, you’ll want to make sure that no extra compound remains on the surface of the floor. Use the trowel’s flat edge to smooth each patch and make sure the floor stays level. Keep in mind that bumps and uneven areas in the concrete floor can cause the tiles to break or rock after installation.

6. Fill Any Depressions

If the concrete floor has any depressions or flaws from the original installation or later damage, you’ll need to repair them, too. Use the concrete patching compound to fill any depressions, taking care to keep the surface of the floor level. Allow the floor surface to dry for at least 12 hours, and make sure the floor is completely dry before moving on to the next step.

7. Apply the Sealer

After cleaning, patching, and repairing the concrete floor, you’ll be ready to seal it. This process creates a protective layer that prevents moisture from seeping through the concrete and into the tile floor.

Use a roller with an extended handle to apply the concrete sealer. Be sure to cover the entire floor to create an effective protective layer. Take care to keep the surface level as you go, and avoid building up uneven layers of sealer. Allow the sealer to dry completely.

8. Lay the Membrane (Optional)

If you’ve decided to use an uncoupling membrane between the concrete floor and the tile floor, you can put it in place after applying the sealer. Follow the manufacturer’s instructions to lay the membrane evenly across the concrete floor.

Patching and sealing a concrete floor takes extra time and effort, but these essential steps ensure that the surface will support the tile for years to come. Once you’ve prepared the concrete floor, you’ll be ready to lay a tile floor and create your ideal design.