Customer Advice for Outdoor Tiling

Here is some advice for customers planning on installing tile outdoors, such as on a porch, patio, verandah, or balcony.

• Lay a concrete slab first. While concrete paving stones can be laid on a gravel base, tile cannot. The slightest irregularity in the base will lead to tiles cracking.
• Using a level make sure the slab is flat, or use a thin cord to create a fractional slope for drainage. If the slab is an old cracked one it may be necessary to lay a screed. Also even if you are tiling on an existing slab remember to install a waterproof membrane to prevent rising dampness.
• Choose a tile with a slip-resistant surface that’s rated for outdoor use. The tile should either have an 'R' rating or a Dynamic Coefficient of Friction rating of at least those listed below. You should find these ratings on the specification sheet for the tile.

• Porcelain tile is more durable and absorbs water less than ceramic tile so is less prone to cracking as a consequence of extremes of temperature.
• Clean the concrete slab thoroughly before laying the tile.
• Apply a waterproofing membrane to the slab before tiling or groundwater will seep up and lead to problems like efflorescence and apparent color changes.
• Use a dry-set adhesive that’s rated for outdoor use, preferably epoxy-based or with added polymers.
• Section by section, cover the slab completely with the tile adhesive. Apply it to the back of the tiles too. Never use a spotting technique outdoors - the tiles will crack.
• Choose an epoxy-based grout that resists stains and fading. Grouting is critically important outdoors. Because of the greater temperature range experienced the tiles will expand and contract so expansion gaps are essential.