In this video, Ask This Old House plumbing and heating expert Richard Trethewey offers undermount sink support by helping a homeowner reattach an under-the-counter kitchen sink to a granite countertop.

Project details

Skill

Cost

Estimated Time

How to Reattach an Undermount Kitchen Sink

  • Turn off the water supply to the sink.
  • Disconnect plumbing connections using a wrench and unscrew by hand.
  • Disconnect any remaining sink clips using a screwdriver.
  • Remove sink from granite and set aside.
  • Scrape off leftover caulking on the sink and the underside of the granite countertop using a putty knife.
  • Insert undercounter-mount sink clips into the existing holes in the granite.
  • Loosely screw the machine screws into the brass threaded insets using a screwdriver.
  • Put a bead of silicone caulking around the rim of the sink using the caulking gun.
  • Place the sink back into the hole in the granite and pull it up into place using a string wrapped through the drain.
  • Have another person underneath the countertop to tighten the machine screws into the granite and place the clips under the rim of the sink.
  • Place wood braces tight under the sink for support.
  • Run a finger along the rim of the sink to smooth out caulking and add more as needed.
  • Reconnect pipes and turn the water back on.
  • Wait 24 hours before removing the wood braces or using the sink.

Tools

Tools & Materials

  • Screwdriver
  • Wrench
  • Caulk gun
  • Putty knife