How to Build a Tile Countertop With an Undermount Kitchen Sink

Line up the sink template provided with the undermount kitchen sink on a plywood counter surface so that it sits an equal distance from the front and back of the counter. Draw around the template to mark the location for the bowl of the sink. Cut along the lines on the counter to remove the plywood in the area where you want the sink to go.

Use the circular saw to make several lines of cuts, roughly 6 inches in length, along the countertop. Maintain spacing of approximately 2 inches between the end of each cut and each line of cuts.

Cover the plywood surface in roofing felt so that the felt hangs off the edge of the counter and lines the two to three inches at the base of the wall. Tape the felt in place with masking tape. Mark the hole in the counter for the sink with chalk on top of the felt.

Layer wire mesh over the roofing felt so that it covers the entire counter surface. Staple down the wire mesh through the felt.

Screw solid metal cap strips to the front and any side edges of the counter that do not sit against a wall to create a wall at the countertop's perimeter. Keep approximately 1 inch of the cap strip sitting above the surface of the counter.

Mix Portland cement according to the directions on the cement packaging listed for wall mortar. Spread the cement over the lined plywood countertop surface with a trowel until it reaches the top of the cap strips. Drag the edge of a metal ruler over the surface along the tops of the cap strips to skim off the top of the cement.

Remove the cement in the area of the sink with your hands, pushing the cement outside the marked edges to leave the sink opening free. Slide the undermount sink through the opening created for it, pressing the sink down until the top of the flanges that hold the sink on top of the countertop sit level with the top of the mortar bed. Lodge wood pieces beneath the undermount kitchen sink to hold it in place while the mortar dries for at least 48 hours.

Apply silicone caulk around the edge of the undermount sink where it meets the dried cement. Allow the silicone caulk to dry for 24 hours and wipe the top of the cement bed down with a tack cloth to remove the dust.

Spread tile adhesive over the dried cement and lay tile on top of the cement surface from the outside edges of the countertop inward toward the edges that touch the walls and the sink. Use a tile saw to cut tiles down as necessary. Wait 24 hours for the tile adhesive to dry. Apply grout between tiles and wait another 24 hours for the grout to dry, then caulk around the outside edges of the tile job, including where the tiles meet the sink.