- 1). Build a solid foundation for a new countertop out of two layers of 1/2-inch exterior-grade plywood. Use the old countertop as a template, cut the sink hole out and fasten it to the cabinets below.
- 2). Unroll a sheet of Ditra over the top of the new countertop, and cut it to size with a utility knife and a pair of scissors. Cut the sink hole out so it will be ready for installation.
- 3). Spread a layer of modified thinset mortar directly over the exterior-grade plywood with the straightedge side of a thinset trowel. Comb ridges into the thinset with the tooth side of the trowel. The tooth size should be about 3/16 x 1/8 V-notch. Lay the Ditra directly into the wet thinset.
- 4). Set the Dirta membrane into the thinset with a short, straight piece of 2x4 lumber after the pre-determined edges of the Ditra line up with the plywood.
- 5). Spread unmodified thinset mortar over the top of the Ditra membrane with the straight side of a 1/4 x 1/4 x 3/8-inch tiling trowel (for a 12x12 tile). Comb the ridges into the unmodified thinset. Set the tile of your choice into the wet thinset using spacers for a straight, consistent grout joint. Allow the thinset to dry according to manufacturer specifications.
- 6). Mix a batch of grout with water until the grout reaches the consistency of peanut butter. Place the grout on the tile, and spread the grout out with a grout float. Force the grout into the grout lines so they are completely filled.
- 7). Allow the grout to set up for 15 to 20 minutes. Wipe the grout haze off of the tiles, individually, with a damp grout sponge. Allow the grout to cure for 72 hours. Apply penetrating grout and tile sealer to the grout line to keep stains out of the grout.
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