How Do You Install Underlayment Under Ceramic Tile?
Ceramic tile seems hard as rock, but it’s actually quite fragile if it isn’t laid properly. The most important issue is stability. If the underlayment has any “give” to it, or if it softens over time, that movement will eventually crack the tiles. Cement board is the preferred underlayment for ceramic tile today, because it cuts and installs as easily as drywall but is as solid as a sheet of cement once in place. Getting the cement board properly installed first will make the rest of your project go a lot faster and last a lot longer. Set your first sheet of cement board down in one corner of the floor. Mark around the edge of it with your pencil. Remove the cement board. Spread thinset mortar over the whole area that will be covered by the first cement board sheet, based on the pencil mark. Scrape the mortar over the area with the notched side of the trowel, to put lines in it. Set the sheet of cement board back in place. Screw it down with your screw gun and galvanized drywall screw
