How to Construct and Mortar a Shower Curb

Cut three 2-foot by 4-foot pieces to fit across the length of your shower opening to form the base of the curb. Nail the first piece to the floor, then nail the second piece to the first and the third piece to the second. You can go as high as four if you prefer; the common thickness is just three boards stacked on top of each other.

Measure for the waterproof lining. Check the overall size of the pan and account for 4 to 6 inches wrapping up the walls as well as an extra 10 or 12 inches to wrap over the top and front side of your curb. Cut it with a utility knife and place the liner into the pan. Ensure that it is tight into all inside corners. Fold the inside corners so the material tucks up on itself and tack that in place on the wall studs. Work your way around to the curb.

Slice the liner with the utility knife where it is stretched across the length of the shower curb so the piece folds down over the top of the wood. Press the liner tight to the wood and pull it over the top and down the face. Tack it in place on the face of the curb. Glue your corner pieces into place to cover the bare wood where you cut the liner and cover the gap from wall to curb.

Cut wire mesh down to fit so it wraps across the top, the face and the inside of the curb on top of the liner. Only tack it on the outside face of the pan, because puncturing the inside ruins the waterproof liner. Mix up some cement in your bucket with the mason trowel until you have a damp, sandy mixture that will clump up and smooth over but not so runny that it becomes mortar.

Spread the mortar onto the wire mesh with your flat trowel. Smooth it down across the wire mesh so it covers the mesh with a thin layer of mortar. It doesn’t need to be perfectly level or flat, just roughly rectangular. You can adjust the rest when you install the tile, using the mortar for the tile installation.