How to Install Exterior Ceramic Floor Tile

Updated February 21, 2017

Ceramic tile can give your outside entryway or patio a rich, luxurious look. There are many varieties, colours and patterns of ceramic tile, including some made specifically for outdoors. You can install them yourself--it's just like installing ceramic tile indoors. You only need to be sure that your tile, mortar and grout are formulated for outside and that you apply an under layer membrane on top of the concrete where you will lay your tiles. This under layer membrane helps keep the tiles from cracking during freezing weather. Even if you live where winters are severe, you can have a ceramic tile floor outdoors if you follow the guidelines below.

Choose ceramic tile approved for outdoor installation. Your chosen tile should have a rating from the Porcelain Enamel Institute of "PEI Class 4" or "PEI Class 5." Ceramic tiles thus rated are rugged enough to survive the freeze and thaw cycle and have less of a chance of cracking than do lower rated tiles. Choose a tile that has a rough surface. Wet ceramic tile is very slippery. A tile with textured surface is less slippery, and therefore safer.

Clean the concrete base. Thoroughly clean the concrete slab on which you will install your ceramic tile. Remove any small specks of sand, dirt, paint, grease or anything else that may interfere with the under layer membrane bonding completely with the concrete surface. If the concrete slab is sealed, remove the sealer with a stripper formulated for concrete, following manufacturer's instructions. The cleaner you get the concrete base, the easier the subsequent steps will be.

Apply adhesive for under layer membrane. Use the same multi-flex thin set mortar you will use to set the ceramic tiles. Apply a thin layer of mortar and use a trowel with a ¼-inch square notch to spread it out. Pull the side of the trowel along the mortar and make ¼-inch notches in it.

Install the under layer membrane. This membrane is necessary to keep ceramic tile from cracking. The membrane shifts during freeze and thaw cycles and helps keep the ceramic tile from moving or cracking. Essentially, the under layer membrane is installed similar to vinyl flooring, but be sure to follow the manufacturer's installation instructions.

Lay down the thin set mortar base. It is not necessary to wait for the membrane adhesive to dry completely before beginning to lay the tile. Use the multi-flex thin set mortar that you used to put down the under layer membrane. This type of mortar will give a little when it freezes, saving the tiles from shifting and cracking. Lay down a layer of thin set mortar, putting down only as much as you can tile in about 45 minutes, or a film will form on the mortar which interferes with the mortar and tile bond. Use a 3/8-inch square notch trowel for tiles up to 12 inches square, a ½-inch square notch trowel for tiles from 12 inches to 18 inches square, and a ¾-inch square notch trowel for anything larger than 18 inches.

Install the tile. When working with outside ceramic tile, lay the tiles closer together than you would for indoor installation. This will reduce the overall area of mortar, which thereby reduces the risk of water being absorbed into the tile, which reduces the risk of cracking when it freezes.

Let the mortar dry. Allow to dry as recommended by the manufacturer, usually about 24 hours.

Apply the grout. Once the mortar is dry, apply the grout. Use a grout specifically designed for outdoor installation. The grout is your first line of defence against moisture seeping into the tiles, which will make them crack when it expands upon freezing. Use a grout float trowel to push the mortar between the tiles. Work diagonally across the tiles to avoid digging the grout back out of the openings. Use the edge of the trowel to skim off the excess.

Wipe off the excess grout with sponge. Use a large sea sponge to wipe off any grout that is on the tiles and to smooth over any grout lines that are not smooth. Work diagonally, to avoid marring the grout that is already in place.

Let the grout cure. Allow the grout to cure for up to 48 hours before allowing foot traffic on the tiles.


It is not necessary to apply sealer. If you use materials designated for outdoors it may not be necessary and if done, will have to be re-done regularly.

Things You'll Need

  • Ceramic tile rated for outdoor installation
  • Multi-flex thin set mortar for outdoors
  • Under layer membrane
  • Grout formulated for use outdoors
  • Trowels
  • Sponges
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About the Author

Sharon Sweeny has a college degree in general studies and worked as an administrative and legal assistant for 20 years before becoming a professional writer in 2008. She specializes in writing about home improvement, self-sufficient lifestyles and gardening.