Easier Plumbing with PEX

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Resistance to frost cracking. PEX piping is better than rigid piping at resisting the outward pressure of freezing water. Manufacturers typically test and warrant their aluminum-core PEX lines to withstand five freeze/thaw cycles before cracking may occur. PEX may withstand even more than that, but it isn’t completely immune to frost cracking.

Octopus Manifold & Fittings

To get the most value out of your PEX lines, you need to plan differently for a PEX installation. Instead of following a roadlike network of large pipes that would normally feed smaller ones in straight-line fashion, water flows from the main PEX line to a central location called a manifold, which in turn feeds smaller PEX lines (similar to the arms of an octopus) that supply fixtures directly.

This configuration delivers consistent pressure to all PEX-connected fixtures, because it creates a hub where water is equally directed to various points in the house. The line supplying your manifold should be three-fourths inch in diameter, with half-inch-diameter branch lines sprouting off from the manifold.

To connect separate pieces of PEX to valves, manifolds and joints, you have a choice between compression fittings and crimp-on rings. Compression fittings connect with threaded parts you tighten together. For small jobs involving less than 20 joints, compression fittings are the most cost-effective option for PEX. To attach a compression fitting, just slip a nut onto the PEX, push the cut end of PEX line over the O-ring on the end of the fitting and tighten the nut with a couple of wrenches (see “9 Essential Wrenches and Pliers”).

Compression fittings are faster, easier and safer to install than any solder joint, but the drawback is they are relatively expensive. For smaller jobs, you can justifiably spend $5 or more on a threaded elbow, a connector or a T-shaped compression fitting. But for bigger jobs that require many fittings, the cost will add up.

Professional plumbers almost always prefer crimp-on connection rings because they’re less expensive, and they install faster and easier than wrench-tightened compression fittings — but there’s a catch. Crimping tools can cost several hundred dollars each, and you’ll need one tool for half-inch joints and yet another for three-fourth-inch joints. The price of these tools is justifiable only if you are plumbing more than one building. Crimping tools are durable, which makes them good candidates for a shared purchase among several neighbors. Keep them oiled and indoors, and they’ll last forever.

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