Plumbing With PEX Tubing

By: GeraldJenkins

PEX tubing is an easy-to-install alternative to copper pipe. Long used in radiant heating systems, flexible PEX tubing is perfect for water supply lines because it’s easy to run through walls and floors and simple to work with.

The Advantages of PEX

PEX, a flexible tubing that comes in long rolls, offers several advantages over traditional piping. First, you can usually make long continuous runs, eliminating most elbows and joints. You can snake long runs through joists and studs. Second, PEX doesn’t sweat under high humidity conditions, and it’s also resistant to bursting, even if the lines freeze solid. Third, joints are easier. You add fittings simply by crimping metal rings over barbed fittings using a special crimping tool.

Use the Same Stuff

There are several different manufacturers of PEX. It is very important that you know which brand of pipes you’re working with and install only that manufacturer’s connectors and fittings. If you mix and match materials, you will void your warranty and may fail your inspection. Worst-case scenario: You’ll end up with leaky pipes and water damage. Not all products have recognizable markings on them, so leave a few of the packaging labels on-site to appease the inspector and for future reference.

Make Crimped Joints at PEX Water Line Fittings

The heart and soul of the PEX system is the barbed fitting/crimping ring combination. There’s no need for solder, glue or pipe wrenches—just position the crimping ring over the end of the PEX pipe, slide the pipe over the barbed fitting and use the special crimping tool to compress the ring. Just be sure to center the ring over the barb and depress the crimping tool’s handles completely. Crimp rings and cinch clamps are the two most common methods for sealing PEX water line joints.

PEX Cutter

Cut the PEX off perfectly square for leakproof joints. PEX cutters like this Plastic Pipe and Tubing Cutter are available at home centers and online.

Stab-In Fittings

Use stab-in fittings only where you have access to the joint. These fittings don’t require a special tool. You simply push the pipe into the openings. Press the outer ring onto the fitting to release the pipe.

Cinch Clamps Are Easy

There are many different ways to connect PEX to fittings, but cinch clamps are one of the easiest. They’re readily available and relatively inexpensive, and you know when they’re installed properly because the tab of the clamp will be visibly pinched.

Fittings for a Shower Valve

Use threaded PEX water line fittings for shower valves. Tighten the fittings before crimping the PEX water line. A plastic bracket forms the sharpest 90-degree angle permitted for this brand of PEX.

PEX Shutoff Valves

Crimp special PEX water line shutoff valves into the hot and cold lines. You can also use standard shutoff valves with threaded fittings to transition to PEX.

Drop-Ear Elbow

Use drop-ear fittings designed for PEX for shower arms and tub spouts.

Repair or Replace Kinks

Kinks happen. You can repair kinks with a heat gun, but PEX tends to rekink in the previously kinked spot, especially if the pipe needs to make a bend at the kinked location. It’s best to cut kinks out and use the shorter sections of pipe elsewhere. If you get a minor kink in the middle of a long, straight run and you don’t want to cut it out, heat the pipe with a heat gun and then cover the damaged area with a hanger or abrasion clip. That will help the pipe keep its shape.