How to Install an Insulated PEX Water Pipe

PEX is an insulated plastic water supply pipe first used in Europe but growing in popularity for both residential and commercial construction in the US. The plastic is more flexible and easier to run through walls and floors than standard copper or galvanized metal pipe. It does require special expensive tools to crimp the fittings to the pipe. Rental tools are available at tool rental stores, and the pipe and fittings are sold at home improvement centers.

Things You'll Need

• Pencil
• Drill
• 1-1/2-inch bit
• PEX straps and hangers
• Threaded crimping ring
• Crimping tool
• Go/no-go tool
• Brass or aluminum supply valve
• Teflon tape
• Adjustable wrench
• Threaded hose connecting ring

Instructions

1. Plan the route for the pipe through the wall studs and mark the location of drill holes in each wide face of the stud. Drill holes into the studs to run the pipe. Drill straight through the wood, not at an angle.

2. Feed the PEX piping through the holes in the studs. For multiple line runs, try not to twist the pipe going through the hole--feed it straight through. Anchor the pipe securely to the wall with PEX straps and hangers.

3. Attach a threaded fitting to the pipe by first slipping a threaded crimping ring over the end. Squeeze the PEX crimping tool over the crimp ring and apply pressure until it crimps and bites into the PEX side. Push the go/no-go tool over the crimp to see if it was crimped well enough. Repeat the crimp if necessary.

4. Connect a brass or aluminum supply valve to the crimped end of the pipe and tighten it down as you would any other type of water pipe. Apply Teflon tape to the threads and tighten the valve to the threaded fitting using an adjustable wrench.

5. Fit the other end of the pipe to the main PEX water supply board by crimping a threaded hose connector to the pipe for insertion and tightening it to the main board. Turn on the valve to the new line and check the line for leaks at the fittings and crimps.

Tips & Warnings

• PEX is flexible, so it fits into tight spaces and around corners easily.

• Avoid situations where the pipe risks pinching, like between two wood boards, or the line will require replacement at some point in the future.

References

• “The Complete Guide to Plumbing: Expanded 4th Edition”; Editors of Creative Publishing; 2008
• “Smart Guide: Plumbing, All New 2nd Edition: Step by Step”; Editors of Creative Homeowner; 2009