How to Replace a Corroded, Galvanized Drain Pipe With PVC

26 January 2017
 Categories: , Blog

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If you have a galvanized pipe, it will corrode with time, often causing a leak or blockage. It must be replaced right away to avoid extensive damage from the pipes corroding completely. PVC pipes solve this problem. A novice should be able to replace a corroded drain pipe. Here are tips to replace corroded galvanized drain pipes with PVC.

Prepare to Work

For this project, you need:

  • work gloves
  • safety goggles
  • tape measure
  • rags
  • wire brush
  • two pipe wrenches
  • reciprocating saw with metal cutting blade or hacksaw
  • thread seal tape
  • spray lubricant
  • PVC pipe
  • female adapter
  • PVC pipe cleaner
  • PVC cement
  • PVC pipe

Shut off the main water supply to the house from the valve near your water meter. Open a tap nearby to release water pressure.  

Remove the Old Drain Pipe

Attach a metal cutting blade to the saw. Cut the pipe twice between each coupling about an inch apart. If you don't have a reciprocating saw, you can use a hacksaw, but it will take longer. Cut and remove pipes in one-inch sections.

Attach a pipe wrench to a coupling, and use the other wrench to grip the section as you turn the first wrench to the left. The male threaded ends will remain.

If you have difficulty removing the couplings, spray some lubricant on them. Let the lubricant soak in several minutes, then try again. Cut one-inch sections until the pipes are removed. If it fails, saw the couplings off, and replace them with mechanical couplings.

Connect the New Pipe

Clean the threaded pipe ends with the wire brush and rag. Attach thread seal tape to the threaded ends to guard against leaks. Avoid using pipe dope as it doesn't bond well with PVC.

Attach a female adapter to one end, and a rubber mechanical coupling on the other. Detach the metal sleeve, and place it back on the pipe. Push the mechanical coupling back to allow room for the new pipe.

Take measurements from inside the female adapter to the rubber coupling. Cut the pipes to fit. Rub the pipe cleaner on the ends, followed by the PVC cement.

Attach the pipe to the female adapter, rotate it an eighth of an inch to spread the glue, and hold it for several seconds. Place a mechanical coupling over a new piece of pipe, and slide the metal sleeve over it. Use a screwdriver to tighten the connection.

Repeat the process until the new pipes are installed. Restore water, and close the taps. If you don't trust your skill, or the pipe still leaks, contact a plumber like Reeves Plumbing & Heating.