Polybutylene Pipe

Connecting to Mobile Home Gray Tubing

Trailer home
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Polybutylene pipe is the gray tubing that was made between the late 70’s and mid 90’s. It was used on both stick built homes and mobile homes but this article focuses on mobile home repairs involving PB pipe. Making repairs and connections in Polybutylene pipe can be a challenge because the Quest fittings are no longer made. So, unless you are ready for a complete repipe you will need to transition to another type of pipe when making repairs.

There are a couple of options when selecting what type of fitting to use for the transition from Polybutylene. The outside diameter of PB tubing is the same as for PEX, CPVC, and copper pipe so push fit fittings is one option you can use. The other is to use a specific transition fitting.

Push-Fit Fittings

For accessible areas push fit fittings, like Sharkbite or Gatorbite, are the easiest way to make a repair.

  • Pinhole leaks - When you find a small leak in a straight length of pipe under the mobile home or other accessible location a push on fitting can be used for a quick repair. Simply cut out the pinhole area and push on the repair coupling. Be sure to measure so you don’t end up cutting more of the pipe than necessary.
  • Changing shut off valves and flex lines for a fixture - Push on shut off valves are a good option for this also. With new flex lines and a push on shut off valve, you can change the water supply lines to a toilet or faucet in minutes. All you need to do is remove the old flex line from the fixture, measure and cut the Polybutylene pipe to length (shut off the water to the house first), push on the new shut off valve and connect the new flex line. Don’t forget to check for leaks several times after turning the water back on.
  • When replacing large sections of pipe - you can use push on couplings to transition from PB to PEX, CPVC, or copper when redoing a large section of pipe. It is a great way to break up a repipe into segments if you don’t want to do it all at once. Connect to the PB pipe under the house with a push on fitting and run the new pipe from there.

    PB by PEX transition coupling:

    For inaccessible repairs, the best option is to use a transition coupling to go from Polybutylene to PEX pipe. The PB by PEX transition coupling is made of brass and it compensates for the difference in inside diameter of PB pipe and PEX. This transition coupling also has two different crimp rings, one that is specifically meant to be used for PB, and the other for PEX.

    • Leaks inside walls - a PB pipe (or joint) leak that is behind a wall should be repaired by replacing the section of PB pipe. Use a transition coupling to convert that section to PEX. You can transition close to the leak or follow the length of pipe to where it comes up through the floor and transition below the floor level.
    • Replacing a valve in the wall - when installing or replacing a shower valve, for example, it is best to use a transition couplings to connect to the PB pipe if there is not going to be an access panel installed.
    • Replacing washing machine valves - push on washing machine valves are available but often difficult to find so the transition fitting is often the most convenient option. After transitioning to PEX you can install the washing machine valves made for PEX tubing.