Slate tile can be installed just like flagstones for patio settings. Outdoor Slate Tile: Flooring Options + Expert Tips. Put water in the bucket first, then add the mortar gradually until you find the right consistency. You may want to order five percent more tile in case of breakage. My understanding is that the limestone dust would not 'set' to the form of the tile, therefore the slate would rock and subsidently crack. This will make the grout moisture resistant, which is especially important on outside tile jobs. Concrete is considered an acceptable substrate for ceramic tile and natural stone installations, such as slate tiles. Tile the next row above in the same manner. ft. / case) Using recycled forms or inexpensive 2x4s, create the frame for the patio. If your old ceramic tile is worn or dated, you can lay new tile right over the old, and avoid the huge job of tearing out the old tile. Slope ensures proper drainage to discourage standing water that can affect your slate. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/4\/4b\/Install-Slate-Tile-Step-1.jpg\/v4-460px-Install-Slate-Tile-Step-1.jpg","bigUrl":"\/images\/thumb\/4\/4b\/Install-Slate-Tile-Step-1.jpg\/aid4063857-v4-728px-Install-Slate-Tile-Step-1.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"