how to extreme

PEX Plumbing for the DIY’er

PEX, Plumbing - Directory June 15, 2011 Sonia


 

By Matt Weber, Photos By Hal Jones

 

Faster, Easier and Less Expensive than Old-fashioned Plumbing Methods.

 

The evolution of plumbing has given rise to PEX as a new standard in construction. Whereas traditional copper supply lines still provide a very strong, reliable connection for water lines, the metal is much more expensive to purchase and more time-consuming to install. PEX supply lines offer a comparatively easy-to-install solution, and the material cost is much less. For these reasons, professional contractors are using PEX more and more, and do-it-yourselfers can take a cue from the pros.

 

Why PEX?

“Builders around here have pretty much moved exclusively to PEX for new construction,” says Richie Hamilton, professional builder/remodeler in Birmingham, Alabama. “Since copper is so expensive, a lot of contractors have problems with thieves breaking into homes under construction and tearing the copper right out of the walls to get the salvage cost.” This means not only are those contractors forced to replace the high cost of copper, but also forced to spend time, money and labor on reinstallation—not a good prospect for a builder’s bottom line.

PEX is cross-linked polyethylene pipe. It was developed in the 1960s and introduced to the United States in the ‘80s. After under-going several manufacturing processes, the material becomes resistant to extreme temperatures (hot or cold). It also resists deformation from long-term exposure to stress, as well as chemical attack from acids and alkalis. PEX is flexible and suitable for use in temperatures below freezing and up to 200 degrees Fahrenheit. This makes PEX an excellent piping material for hot and cold water potable water systems, as well as radiant heat flooring.

Its flexibility is one of the major advantages of PEX. When running supply lines through a stud wall, PEX is easy to thread through the stud holes without binding against the wood, as a rigid copper pipe can do. When a pipe reaches a corner, a copper pipe must be cut, then fitted with a 90-degree elbow, fluxed and soldered, and then joined to a second length of pipe using the same soldering process. With PEX supply line, simply bend the flexible pipe through the corner studs—no joint is necessary. Fewer joints save time, which can bring down costs for the contractor and the homeowner. Fewer joints also mean less chance of a leak. PEX is available in 1/4- through 1-inchsizes, and the material’s flexibility allows it to expand and contract to reduce the risk of a burst pipe. Furthermore, flexible systems are quieter than rigid piping.

On top of all this, a PEX system has a shutoff valve at each supply line. This makes it more convenient to cut off the water supply when making repairs or working on plumbing fixtures.

Note: PEX tubing is approved in all the current model-plumbing codes, but some jurisdictions may not have amended the code to include PEX tubing. Contact the local authority with jurisdiction over plumbing to verify the acceptance of PEX tubing for plumbing applications in your area.

Shown is a PEX manifold built by the EHT staff during a recent bathroom addition. The manifold allows different lines of the pipe to be shut-off for easy maintenance or repairs.

Shown is a PEX manifold built by the EHT staff during a recent bathroom addition. The manifold allows different lines of the pipe to be shut-off for easy maintenance or repairs.

 

Weigh Your Options

All this love for PEX doesn’t mean the world doesn’t still love copper. If copper wasn’t such a hot commodity, the material wouldn’t be so expensive, and thieves wouldn’t target it.

Copper has been used as a plumbing material for decades and has proven to be durable, resistant to bacteria and—when compared to iron pipes—relatively easy to install. Copper resists corrosion and is also unaffected by ultraviolet rays, which is one advantage copper has over PEX. The PEX material can deteriorate in the presence of the sun’s ultraviolet rays, which is why PEX should not be used in exposed outdoor applications.

Copper is also recyclable. PEX is not. This makes copper the more sound environmental choice for the green-minded homeowner.

To determine a price comparison between the two materials, I took a trip to my neighborhood Home Depot to see what was selling. At the time of publication, 10 feet of 1/2-inch Type M copper pipe (the type typically used for water lines) sold for $11.81, which equates to $1.18 per linear foot. On the other hand, a 50-foot coil of 1/2-inch PEX pipe sold for 13.96, which equates to only about $0.28 per linear foot.

All PEX connections begin with a good, square cut on the pipe end. Here we’re using the new Milwaukee12V pipe cutter.

All PEX connections begin with a good, square cut on the pipe end. Here we’re using the new Milwaukee12V pipe cutter.


Installation Techniques

eht-pexheat-electric-bannerCurrently three different techniques are available for installation of PEX plumbing systems.

Push-fit Connections. Soldering copper pipe requires hand tools such as a propane torch, a flux brush, a pipe-cleaning tool and a pipe cutter. It’s a time-consuming process. However, copper pipe can also be installed with the same modern push-fit connections that work with PEX and CPVC.

For new installation and repair of potable water supply lines, push-fit connections provide a quick way to join pipe, requiring no soldering, clamps or glue. Push-fit connections utilize a compression fitting to join the pipes, and are certified up to 200 PSI and 200 degrees F. Installation of these fittings is super simple, paving the way for all manner of DIY applications.

To make a push-fit connection, first make a square cut on the end of the pipe. Sand down any rough edges or debris. Mark the depth of the pipe that will be housed in the push-fit connection. Push the fitting together up to the depth mark so it “clicks,” and like magic the connection is complete—it takes all of 3 seconds. The combination of push-fit fittings, manifolds, valves and PEX tubing is the fastest way to plumb virtually any residential project.

After making a square cut on the pipe, mark the depth of the pipe that will be housed in the push-fit connection.

After making a square cut on the pipe, mark the depth of the pipe that will be housed in the push-fit connection.

Push-fit connections provide the fastest and easiest method to connect PEX, copper or CPVC pipe. Some push-fit connections include a reinforcement ring to be placed inside the end of the pipe, so the pipe end retains its round shape as the connector crimps over it.

Push-fit connections provide the fastest and easiest method to connect PEX, copper or CPVC pipe. Some push-fit connections include a reinforcement ring to be placed inside the end of the pipe, so the pipe end retains its round shape as the connector crimps over it.