This thick-bed installation relies on a troweled mortar mix, which when properly mixed is like a sandy clay. Floating a thick bed takes two steps: floating the sloped sub-base for the membrane and floating a reinforced top floor that follows the slope of the sub-base. Because of its considerable weight, you should install it only on a slab or properly supported wood subfloor. You’ll need to devote two to three days to frame the enclosure, float the floor, and tile and grout the interior. Before you begin, strengthen and repair the subfloor. Also make sure you’re comfortable with basic framing, mixing and floating mortar, setting tile, and grouting. Editor’s tip: The mortar for a shower enclosure should be just wet enough to clump together. You’ll know it’s right when you squeeze it and it just holds its shape. Editor’s tip: If you do happen to puncture the liner, it doesn’t mean you have to take the whole thing up and start over. Clean the punctured area thoroughly and cut a patch at least 2 inches wider than the puncture. Apply the appropriate solvent to both the membrane and the patch. Roll the patch flat and let the repair dry. Fill the pan with water to about an inch from the top of the membrane. Let the water come to rest, mark its level on the side of the pan, and let the water sit for 24 hours. Then check the level. If it’s still at the mark, the pan is watertight. If the water is below the mark, the membrane has a leak somewhere. Check the surrounding floor for water, which would have come from a leak in the side. If there’s no evidence of water, pull the plug, expand its diameter a little, and repeat the test. If the water has drained out completely, it’s probably leaking at the drain flange, which is either too loose or too tight (and may have cut the membrane). Tighten the bolts if they feel too loose. If the flange has cut the membrane, remove the drain plate, let the membrane dry completely, and solvent-weld a patch at least 2 inches larger than the puncture.
