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How to Seal Concrete Floors Before Tiling

By Paul Ramone ; Updated September 21, 2017
Prepare a concrete floor for tile with a waterproof sealant.

Laying down a tiled floor onto an unsealed and unprotected concrete surface is a recipe for disaster. Any water that could seep through the tiles will easily get caught on top of the concrete and even erode it over time. With a waterproof seal coating, however, you can properly prepare the concrete floor for the tiles and ensure that the surface will last. Even those unfamiliar with the process can finish applying the sealant in just a few hours.

Step 1

Remove objects from the floor and sweep up loose debris with a push broom.

Step 2

Take the screw cap off the top of a pump sprayer and place a funnel into the opening.

Step 3

Slowly pour a concrete degreaser into the sprayer tank.

Step 4

Remove the funnel and fasten the screw cap.

Step 5

Pump the sprayer as instructed in the user's guide and apply the degreaser to the floor with long, even swipes of the sprayer's wand.

Step 6

Wait 12 to 15 minutes for the degreaser to break up any oil stains or deposits, then scrub the concrete with a nylon brush.

Step 7

Rinse down the entire surface with a hose. Wait for the concrete to dry completely before continuing with the sealing process.

Step 8

Fill a paint tray with concrete sealant.

Step 9

Run the end of the paint roller through the sealant so that it is evenly covered and then apply the sealant onto the concrete with long, even strokes. Make parallel strokes with the paint roller that are overlapping slightly so that you cover the entire surface. Once you have covered the entire floor, wait 24 hours for the sealant to dry before beginning the tiling job.


Things You Will Need

  • Push broom
  • Pump sprayer
  • Funnel
  • Concrete degreaser
  • Nylon brush
  • Hose
  • Paint tray
  • Concrete sealant
  • Paint roller