How to Replace an Undermount Sink in a Kitchen With Granite Counters

Place a bucket or tray underneath the sink to catch any water, then disconnect the plumbing. Remove the P-traps, tailpieces and any other section of drainpipe connected to or in the way of the sink removal using the adjustable pliers.

Cut the silicone adhesive in the joint between the countertop and sink using a razor knife. Silicone adhesive seals this joint to prevent water seepage and to help bond the sink to the counter.

Loosen and remove the mounting clips or clamps holding the sink in place using an applicable sized screwdriver or nut driver. The mounting clips screw to threaded nuts or brackets that are attached to the bottom of the granite with two-part epoxy.

Press down on the sink carefully to release it from the counter. It might be necessary to re-cut the silicone adhesive between the countertop and sink before it's loose enough to remove.

Clean any remaining silicone around the sink opening by scraping with a flat razor blade.

Wipe the bottom of the countertop around the sink opening with a rag and acetone to remove any dirt, debris or silicone residue.

Place the new sink inside the cabinet underneath the sink opening. Use the caulk gun to apply a generous bead of silicone around the sink lip that will contact the bottom of the countertop. Lift the sink into position and align it with the opening in the countertop.

Place a 2-foot bar clamp in the sink drain openings. The stationary part of the clamp inserts into the sink drain opening while the adjustable end of the clamp rests on the piece of 2-by-4 straddling the sink opening. If the sink has two drains, place a clamp in each drain opening.

Align the sink with the sink opening and tighten the clamps to draw the sink tight with the countertop. Ensure that the overhang or reveal is even around the sink opening and adjust it if necessary. Smooth the silicone into the joint with your finger. Remove excess silicone from the sink or countertop with a clean, dry rag.

Replace the sink mounting clips from underneath the countertop and tighten until they're snug. Do not over-tighten the clips, as this can dislodge the nuts from the epoxy that bonds them to the countertop. Allow the sink to set for 24 hours before removing the clamps.

Remove the bar clamps and install the sink baskets. Apply a generous bead of plumber's putty around the lip of the sink basket and press it into place. From underneath the sink, place a rubber washer followed by a retaining nut on the sink basket. Tighten the retaining nut until it's very snug using adjustable pliers or a sink basket wrench. Remove any excess plumber's putty with your finger.

Re-connect the drain lines, P-traps or other applicable plumbing to the sink. If your sink is the same model as the one replaced, most of the plumbing should fit without any major modification.