Easier Plumbing with PEX

Image Gallery PEX piping is pliable, and installs quickly and economically, making it perfect for do-it-yourself plumbing projects. MICHAEL MAXWELL

June/July 2006

By Steve Maxwell

Next time you need to replace pipes in your home, consider an alternative to rigid piping that comes in rolls, can be cut easily to any desired length, and requires no soldering and very few joint fittings. Generically called PEX-AL-PEX, this flexible plastic piping is so easy to install that you can handle most projects quickly on your own.

Although PEX-AL-PEX is relatively new to North America, it’s approved in major plumbing codes, and professional plumbers are increasingly choosing PEX-AL-PEX because of its successful 30-year track record in Europe. It’s a little more expensive than rigid copper piping — but the advantages outweigh the extra cost. Plus, you can save money by doing the job yourself. You can buy it at major hardware stores, where it’s usually sold as water supply piping and infloor radiant-heat lines. When you buy PEX at the hardware store, make sure the tubing is stamped with “NSF-61” or “NSF pw” (for potable water), which distinguishes it from the PEX that is used only for infloor radiant heating applications.

PEX-AL-PEX is named for its sandwich-layered construction that uses cross-linked polyethylene plastic as the outside layer (PEX), aluminum as the middle layer (AL) and another layer of cross-linked poly on the inside. To keep it simple in this article, I’ll refer to PEX-AL-PEX as just PEX, though that name also is used for plastic-only water supply lines.

PEX is worth considering for your next plumbing project for three reasons:

Flexibility. PEX can be hand-bent in any direction and will remain in a fixed position. This allows you to work it around and through existing floor joists, walls and frame members. PEX bends tightly up to a 3-inch radius without forming kinks, which significantly reduces the need for most elbow joints.

Easy joint assembly. PEX joints usually are made with either threaded compression fittings or crimp-on connection rings (both described below). These joints are fast and easy to complete, and you don’t have to torch and solder them, except when you connect new PEX lines to existing copper supply pipes. But even connecting copper pipes to PEX is a job that most people can do themselves — all it takes is some basic knowledge of plumbing skills and PEX joints (see “Connecting to Copper”).