Many types of hard tiles, such as slate, ceramic, and marble, aren't good for outdoor use, because they can absorb moisture, which can freeze and crack the surface. Porcelain tiles, however, are an excellent choice for outdoor installations, given their high density and non-porousness. Although porcelain is laid like any other tile, make sure all materials are rated for outdoor use before starting your project.
Only tile over an area of concrete that's solid, clean, and free of cracks. Use cement to patch any cracks or holes. Wash and rinse the area thoroughly, and allow it to dry completely.
Lay a tiling membrane over your base to help absorb movement from the ground. Install tile membrane, which is rolled sheets of thin fibrous material that provide a buffer between the tiles and concrete. It attaches to the concrete with the same thinset adhesive you use to install the tiles. Starting in one corner and working in sections, spread the thinset adhesive about 3 mm (1/8 inch) thick with a notched trowel.
Roll out the sheets of tile membrane in rows over the adhesive as you spread it. Press down the surface of the membrane with a wide flat trowel to secure it to the adhesive. Don't overlap the edges of the membrane rows. Butt them up against each other, cutting the membrane at the edges of the area with your razor knife.
Use your chalk snapline to divide the area into four equal sections, stretching it across the centre of the area, snapping it up so it leaves a line on the membrane. Do the same thing in the other direction.
Tile from the middle, spreading down adhesive with your notched trowel in one of the corners where the four sections meet, pressing the first tile into place.
Lay subsequent tiles using the lines as a guide, putting 6 mm (1/4 inch) plastic spacers between them. Lay all of the full tiles first. Then go back and lay partial tiles at the edges.
To cut the tiles, mark them on the surface at the necessary size and slowly feed them through your wet saw. Once all of the tiles are laid, remove the plastic spacers, and let the tiles set for a day.
Apply your grout with a rubber grout float, pressing it into the lines between the tiles. Use a damp sponge to wipe off the excess grout. Let the grout set for a week before sealing it with your grout sealer and brush.
Make sure your local weather forecast predicts clear skies for a few days before you start your project. If it does happen to rain, cover everything with a plastic tarp.
Wear eye protection when using a wet saw.