In July, JLC spent some time on site with tile contractor Tom Bouchard and fellow tile pro Bob Vedder as they prepped and tiled two bathrooms in a custom house under construction by architect and builder Caleb Johnson on the rocky shore of Maine’s Casco Bay. This week, we take a look at one step in the job: building the shower curb and getting it ready for tile.

Tom Boucher trowels a measured amount of mortar onto a laminated Kerdi-Board shower curb using a Kerdi trowel with one-eighth-inch teeth.
Credit: Ted Cushman/JLC Tom Boucher trowels a measured amount of mortar onto a laminated Kerdi-Board shower curb using a Kerdi trowel with one-eighth-inch teeth.

The job is simpler than it used to be, says Tom Boucher. In the old days he would build up the curb using sawn lumber, then cover it with cement board. These days, he uses components from the Schluter Kerdi system, as shown below: he cuts pieces to fit the opening from Schluter Kerdi-Board, mortars the boards together to build up the curb, covers the rough curb with a measured amount of mortar, and applies Kerdi membrane over the fresh mud to integrate the waterproof curb into the continuous waterproof shower enclosure. Once the Kerdi-Board shower walls, floor, drain, and curb are all sealed at the joints with mortar and Kerdi membrane, says Boucher, “you could turn the shower on, and nothing would leak.” For a more detailed look at the curb construction and waterproofing process, see the slideshow.