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Published May 17, 2011

Q:Money is very tight and I can't afford to hire a plumber to install new water supply lines in my home. I've seen the PEX plumbing tubing and think that's the way to go, as there are no soldered joints hidden in the walls. Is it hard to install PEX? Am I crazy to think that I can be successful doing this?

A: More folks are doing home repairs and remodeling - not because they want to, but because they have to. That means there's lots of opportunity to make mistakes and to build confidence. Let's put you in the second group.

First, be aware that some cities and towns don't allow unlicensed people to work on the potable water supply systems in their homes. If your home is connected to a municipal water system, water in certain situations can flow out of your home and into the water mains outside your home. If you've made connections to the system that allow polluted water to flow into the water pipes outdoors, you can make many sick. It's serious business.

Let's assume you're allowed to do the PEX plumbing installation work. I think that, with a little practice, you can do this major job successfully. There are a few areas where you'll need some sweet skills to ensure you don't have a leak.

There are many advantages of PEX tubing and plumbing fittings. As you've already noted, since the PEX piping is similar to electrical wiring, there are no joints in the pipe if you decide to install a separate pipe to each fixture from your main mechanical room where the water supply enters your house. That one characteristic of PEX is an enormous time saver.

The PEX tubing I've worked with and had the best success with is a special plastic that has a memory. Don't ask me how they figured it out, but when you stretch the material it fights to go back to its original shape and size. This property allows the piping and little compression collars to grab tightly onto the knurled surface of the male adapter fittings. This is what creates the leak-free connections between the PEX tubing and a manifold or a valve at the end of a run.

To stretch the piping, you need a special tool that has an expanding cone tip. As you crank the tool, this cone expands the plastic. The warmer the pipes, the easier it is to accomplish.

This special tool can either be hand-powered or a cordless electric tool, which is very handy. You'll have to get one of these tools to do the job, so give a serious look at the cordless tool. If you buy a new one, once you've completed the job, you can sell the tool and probably get back 65 percent of the price you paid.

The only problem area would be installing the two manifolds in your mechanical room. These are usually made from copper and have a shutoff valve at each port where you connect a water line. You'll have to securely attach the manifold to the wall and do some expert soldering to connect the manifold to your water supply.

Some plumbers are moving away from the manifolds and installing PEX piping as they would traditional water supply lines. In these cases you do end up with joints hidden behind walls. If you decide to install your system like this, you need to be very conscious of water pressure and friction losses. You'll have to install a 1-inch main trunk line that eventually downsizes to 3/4-inch and then 1/2-inch pipes that supply each fixture.

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