How to Convert Your Single Sink into a Dual Sink

From on April 02, 2009 in Bathroom Remodel

dualsink.jpgPhoto credit: JDog Construction

It should be a snap to convert a single sink into a dual sink. Both sinks will need to be tied to a single main drain before going into the wall or floor. If you tie the two sink basins together first, then you’ll only need one trap rather than two. Also, make sure the water supply lines are attached with dual shut-off valves. The dual sink procedure is really very forgiving. Here’s how to convert a single sink into a double sink.

  1. Drain and vent lines are a good place to start. Figure out the size of the drain pipe. If the PVC pipe coming out of the wall is 1-1/2 inches, you’ll need to downsize the next branch of pipe to 1-1/4 inches; this way sinks drain trap will fit better. When the sinks drain you want smaller drain lines leading into larger ones. An important note: make sure that you split the larger drain with a “Y” fitting since the “Y” attachment will branch off at a 45 degree angle. This allows proper water flow and venting to occur.
  2. Next, attach tee lines off the hot and cold water and tie them together. From that point use flex lines to hook up your individual faucets. Make sure to match the proper flex tubing with the right tee lines and then you’ll be in business.
  3. Since you’re trying to service two faucets with one line, you may encounter a flow problem, but here’s a solution. Make all of your tee fittings installed to a ½ inch, and then add four new stop valves. The new configuration should consist of two for the cold lines and two for the hot lines. Each faucet will have its own hot and cold supply lines. This should eliminate any low flow problems. However if problems persist, be sure to contact your local plumber, they’ll be able straighten things out very quickly.