How to Install PEX Water Supply Piping

PEX Tubing, "Tee" Fitting, and Crimp Rings

PEX pipe is a flexible plastic pipe available in 3/8-inch, 1/2-inch, 3/4-inch and 1-inch diameters and is used for hot and cold indoor plumbing (instead of copper or galvanized pipe) and for radiant floor heating. There is a wide variety of fittings available. The pipe and the fittings are easy to install. Installation does require the use of a specialized PEX ring crimper, which is expensive to buy but inexpensive to rent, providing they are available for rent in your area.

Things You'll Need

• 90-degree angle drill 1 1/2-inch spade bit PEX pipe PEX pipe fittings PEX crimp rings PEX crimp tool PEX "go/no-go" gauge Pex or PVC cutting tool PEX straps and hangers Metal stud plates

Instructions

1. Drill holes through wood wall studs with a 90-degree angle drill and a 1-1/4- to 1 1/2-inch spade drill bit where you would like to run the PEX pipe. Use PEX straps and hangers to secure the PEX pipe to studs and other support structures. Use PEX straps and hangers near bends to reduce the strain on fittings and to hold the pipe in place.

2. Thread the pipe through the holes while a helper feeds the pipe from a larger roll. Apply metal plates to the studs where the holes are drilled through the studs so screws and nails will not accidentally puncture the PEX pipe when the walls are finished.

3. Apply fittings to the pipe by sliding a crimp ring over the pipe. Insert the end of the fitting into the pipe so the end of the pipe touches the fitting shoulder. Slide the crimp ring over to the end of the pipe leaving 1/8 to 1/4 inch of pipe exposed. Use the crimping tool to crimp the ring tightly into place. One crimp usually does the job, but a second crimp may make the joint tighter.

4. Slide the "Go/No-go" gauge over the crimp ring to determine if the ring was crimped successfully according to the directions in the installation guide (see Resources).

5. Repeat Steps 1-4 until all of the pipe is installed and all of the fittings are crimped into place. Turn the main water supply on and check for any water leaks in the joints. Redo the leaking joints and test again.

Tips & Warnings

• PEX pipe is available in 100-foot rolls, so a long continuous run of pipe is quick and easy to install. PEX pipe expands and contracts 1 inch for every 100 feet of continuous pipe for every 10 degrees or temperature change, either hotter or colder, so you have to compensate for this expansion and contraction by adding a little slack to the pipe as it is installed. Do this by 1) Cutting the pipe a little longer than it needs to be; 2) For horizontal runs, apply straps and supports firmly, but do not tighten them around the pipe. Allow the pipe to move freely in the strap or support to allow for pipe movement; 3) For vertical runs, create a 12-inch loop in the pipe, or add 12 inches of extra slack in a run between two studs. Straps can be as much as 6 feet apart when the pipe is continuously supported from underneath. When hanging the pipe in a horizontal run (e.g. over the length of a floor joist, etc.) use a hanger every 32 inches to support the pipe correctly. Vertical runs need to be supported at every floor level.

Resources

• PEX Pipe Installation Guide