Laying Patio Tile
An outdoor tile surface comes under a good deal of stress, so use the best-quality materials available for each step. Talk with your tile dealer about specific products that will perform best outdoors. Don’t give water any chance to enter or hide beneath your tiled surface. Pack the grout joints as tightly as possible, then seal them carefully. Renew the grout sealer and caulk or sealant in expansion joints regularly.
Tools: Notched trowel, snap cutter or wet saw, rubber mallet, grouting float, sponge.
1. Apply an isolation membrane. A trowel-applied isolation membrane is a caulklike substance that never fully hardens. It forms a layer that separates the tile from the patio, making it less likely that cracks in the concrete will translate to the grout and tile. Apply it with the notched side of the trowel, then smooth it with the flat side.
2. Dry-set the tiles. Allow the isolation membrane to cure. Lay the tiles in a dry run over at least part of the surface before mixing any adhesive; this is particularly important if you will be setting tiles in a pattern. If the patio is slightly out-of-square, dry-setting gives you a chance to judge how best to arrange and cut tiles.
3. Use a wet saw. For thick tile or stone, or to cut inside corners accurately, rent a wet saw. It quickly and cleanly slices through the hardest of materials, even granite. To keep the blade from getting dull, keep water running on it at all times.
4. Apply the mortar. Use thin-set mortar mixed with a liquid latex additive. Apply the mortar in two steps. Trowel on a smooth base coat, about 1/2 inch thick. Then comb the surface with the notched side of the trowel, taking care that the notches do not penetrate through to the concrete base. Use long, sweeping strokes.
5. Set the tile. Give each tile a twist as you push it into the adhesive. Take care not to slide the tile into position. Use spacers to keep the tiles aligned. If the tiles are not flush, use a beating block and hammer or a rubber mallet to gently tap them into alignment.
Expansion Joints - Tile is going to expand and contract on a patio installation even more than it will indoors. You can minimize damage due to this movement by placing expansion joints between tiles no more than 16 feet apart and wherever the tile meets another surface, such as the foundation of the house or stairs. Ideally, an expansion joint should fall over a similar joint in the concrete pad. After grouting the other joints, fill the expansion joints with caulk or sealant.
6. Grout the joints. Allow time for the adhesive to set (usually one or two days). Mix the grout of your choice, using latex additive to keep it from cracking later on. Push the grout into the joints with a grouting float, making sure you move the float in at least two directions at all points. Once the joints in a small section are fully packed, scrape with the float held nearly perpendicular to the tiles to remove as much waste as possible. Clean the grout from the tile surface and make smooth grout lines, first by laying a wet towel on the surface and pulling it toward you, then by wiping carefully with a damp sponge. Sponge-clean the surface several times. After the surface has dried, buff with a dry towel.
7. Caulk the expansion joints - Choose a caulk or sealant that closely matches the grout in color. Clean the joints of any adhesive that may have been squeezed up, then clean and vacuum the joint. Run a neat bead of caulk or sealant along the expansion joints. Shape the joints, if you like, with the back side of a spoon, a dampened rag, or your finger.
Tiling Outdoor Steps
Although not often seen today r\ in new construction, tiled stairs have a long and rich history. You can add tile to both the risers and the treads of a concrete stairway. On a wood stairway, a popular choice is to install tiles on the risers only. Risers are not stepped on, so they can be covered with thin wall tiles if you prefer. Cover the entire riser, or use a few decorative tiles to accent. Large, unglazed paver or quarry tiles are attractive for exterior treads. The tiles should be at least 1/2 inch thick and slip resistant. Special bullnose tiles are available that can extend over the riser. Install riser tiles before you install the tread tiles.
Tools: Tape measure, saw, hammer, drill, tiling and grouting tools.
Prepare concrete stairs. Concrete stairs are the best surface for tile. But the concrete must be in solid condition, with no major cracks or other structural damage. Seal small cracks with a concrete patching compound. Repair damaged edges by chipping away any loose concrete, then sweeping and wetting the area. Place a board along the damaged area, then fill it with patching compound or fresh mortar. Smooth with a trowel and allow to set.
Tiling concrete stairs. The most professional installation calls for a new mortar setting bed applied over the entire surface. But you can also tile over concrete stairs following the general guidelines for a concrete patio. Remove oily stains and make sure that the concrete does not contain curing compounds. Spread a trowel-applied isolation membrane before setting tiles. Use bullnose and cove tiles as shown to strengthen the edges and make cleanup easier.
Caution! Safe Stair Dimensions - Before tiling over stairs, make sure they are safe. The treads, the surface you step on, should be about 11 inches deep, although for exterior stairs it is often recommended that they be deeper. The riser, the vertical element between treads, should be about 7 inches high. Check with your building department if you are not sure about your stair dimensions.