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Q.We are building a new home on a slab foundation that is already poured. The customer uses a wheelchair and wants a curbless shower in a bathroom with a tiled floor. Is it possible to keep the bathroom floor level with the finish floors in the other rooms, while still providing some slope for drainage in the shower?

A.Tilesetter Tom Meehan, owner of Cape Cod Tile Works in Harwich, Mass., responds: The only way to install a curbless shower with adequate slope for drainage without raising the floor level higher than the finish floors in other rooms is to jackhammer the slab and drop the floor about 3 inches.

But if the homeowner is willing to compromise, you can install the tile without demolishing the existing slab. After installing the drain assembly, set flush with the slab, install a waterproof membrane like NobleSeal TS (Noble Company, 800/878-5788,, bonded to the slab with thinset. Apply more thinset on the top side of the membrane, and then install a Portland cement mud base at least 1 1/4 inches thick, providing a pitch to the drain. If possible, the slope should be 1/4 inch to the foot; if the slope is any shallower, you risk ponding problems. The last step is to install the tile. This will result in a floor that may be about 2 1/2 inches higher than the finish floor of any adjacent room, depending on flooring material, but a beveled saddle at the door threshold should accommodate a wheelchair.