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Sink Installation By the Numbers

As a local plumbing expert, My Plumber CA knows that there are several competent do-it-yourselfers out there. But we also know that most people haven’t got that much experience doing work on major home systems. Even some of the jobs that seem like they are simple, can end up disastrous if they aren’t done correctly. One of these is a sink installation. Whether you are replacing an old kitchen sink or putting in an entire new bathroom, there are several common mistakes that DIYers make.

Major DIY Sink Installation Mistakes

The most common problem that we’ve seen is a violation of local building codes. This happens because the homeowner doesn’t know the regulations. And, while understandable, ignorance of the law is not a defense, so any home improvements that are not up to code will have to be fixed the first time a licensed plumber is called in.
Many of the following mistakes are also violations of building code:

  • Improperly joining copper pipe to existing galvanized lines
  • Failing to level fixtures
  • Forgetting to use PTFE tape or pipe compound on threaded joints
  • Improperly adjusting stop valves
  • Failing to install an air gap for fixtures
  • Cutting supply lines too short to install shut offs
  • Using improperly sized pipes (usually too small)
  • Failing to remove excess bonding agent from previous installations
  • Compressing pipes while cutting them

Sink Installation Process

Free Standing Sink

  1. Use a cutting wheel to cut the end of the copper supply lines for both hot and cold water. Leave at least 1 ½” of the pipe extending past the finished wall to allow for a shut-off  valve connection.
  2. Build the faucet according to the instructions contained in the packaging (there are simply too many types of faucet to describe in detail here).
  3. Flip the sink over so the bottom is facing up and install the escutcheon (cover plate), coupling nut, compression ring and valve.
  4. Tighten the coupling nut. This will require two wrenches (crescents make this much easier because you don’t have to match the nut and coupling sizes). The nut will make a quick squeal when it has been properly tightened. Do not over-tighten the compression seal. This can cause cracking.
  5. Flip the sink back upright and set it on top of your cabinet (or stand it up if it is a pedestal).
  6. Connect the J-trap to the drain line and the main drain line to the J-trap. Tighten as necessary.
  7. Turn the water on and check the shut-off  valves, drain line and basin for leaks.

Drop In Sink

  1. Make sure the sink that you purchase fits the space in your counter-top. The lip should sit squarely on the routered edge of the hole, within 1/8″.
  2. Install the faucet in the sink body before dropping it into place. You can attach it after the sink is secured, but it will be a bigger hassle unless you have two people that are very good at working with each other. Do not attach the supply lines to the sink, yet.
  3. Set the sink in place and align all the supply and drain lines before screwing it into place. Screw the sink in using the included underside brackets (use the screws that came with the brackets, longer screws will not fasten completely because they will hit the sing edge.
  4. Place a bead of silicone caulk around the top side of the sink. This will prevent water from getting between the sink body and the cabinet.
  5. Turn on the water and check for leaks.

Of course, the easiest way to install a sink is to hire professional to do it for you! You didn’t think we were going to miss an opportunity like that did you? So, if you aren’t a big DIYer or simple would rather spend your Saturday doing something else, give My Plumber CA a call and let us take care of it for you.

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