Installation Guidelines

• Before installing the shower membrane, inspect the subfloor where you will be installing the shower. The floor joists underneath the subfloor should be structurally sound. The subfloor sheathing must also be in good condition. Repair any damaged components before you proceed with the project.
  
  You will need to attach the membrane to the studs of the shower wall, so do not put in the bottom cement board of the walls until after you install the membrane. Install blocking between the studs, which can be used to support and secure the membrane. Now you can complete the installation of the cement boards around the shower walls, but leave about a ¼ inch gap between the bottom of the board and membrane.
  
  Stuff the shower drain opening to keep foreign material out of the opening. Build the shower curb if you have not already done so. Use 2 inch by 4 inch lumber. Attach metal lath to the curb, which will provide a base for the mortar. Staple the lath to the board but only on the exterior side. Lay a bed of mortar. Slope the mortar ¼-inch per foot toward the shower drain. Install roofing felt over the mortar once it has set.
  
  It's a good ideal to take your shoes off if you are working in a sizable shower. This way your work boots won't damage the membrane. Run the membrane up the side walls 12 inches. Make sure that the material doesn't have any creases or wrinkles. Smooth the membrane up along the studs and blocking and fasten the membrane with large-head galvanized roofing nails. Fold the corners and make sure that you penetrate through all layers of the membrane when you attach it to the studs. Extend the membrane up and over the curb.
  
  When you cut the opening for the drain, be care that it isn't too wide. At this point, secure the drain cover in place and tighten the connections. There should be a gap between the drain and the plate of 1-1/4 inch to allow for the mortar thickness. You may want to cover the drain with some masking tape.
  
  Mark the level for the side height of the mortar around the perimeter of the wall. The height is usually 2-1/2 to 3 inches. Again, the floor must be sloped toward the drain ¼ inch per linear foot. When the mortar has set, test the system for leaks. Once you're satisfied that the shower base is leak-proof, you can tile the shower walls. Save the shower floor tile for last.