Pex vs copper. Which stands up better to cold?

pitteach

pitteach

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I am re-plumbing a ground floor bathroom with 2 walls that are shared with the garage. I do need to run 1/2" h/c supplies through these walls and I am not sure if I should use pex or copper. The walls are 2 x 6 with fiberglass insulation. The supplies will be wrapped in foam jackets and foam where they penetrate the studs. I do not anticipate a freezing condition, but I still want to use the material that will hold up best during temperature fluctuations. Access is not an issue and either copper or pex will be fairly easy to work with.
The bathroom was previously done in cpvc which burst because the house sat for a while unheated during the winter.
So the question is... which to use?
 
Without a doubt, PEX. PEX can expand many times its original size without bursting. Even if the copper itself does not split, your plumbing solder will crack. Last winter our basement underwent water damage when the sweated joints failed during exceptionally cold conditions. Your fittings will still be vulnerable, but you'll be much better protected with PEX than with copper.
 
I imagine while the house is occupied the plumbing in this bathroom would not experience freezing temperatues. If the house is going to be unoccupied, wouldn't an oil-filled electric baseboard heater with a thermostat work out a little better than heat tape? I just feel uncomfortable about having the tape inside the wall. Are my fears unfounded? If the power went out, wouldn't PEX be a little better than copper?
 
Doherty Plumbing said:
If the water freezes the pex will still split and rupture. I've seen it MANY times.

The heat trace should be 100% safe inside the wall.
Click to expand...

It depends on the Pex used and several other factors.

PEX AL PEX is not freeze resistant at all!

PEX will normally expand and not split but the distance between brass fittings if between 2" and 7" apart PEX may split.

This was the results of a study done several years ago in a nut shell...
 
Redwood said:
It depends on the Pex used and several other factors.

PEX AL PEX is not freeze resistant at all!

PEX will normally expand and not split but the distance between brass fittings if between 2" and 7" apart PEX may split.

This was the results of a study done several years ago in a nut shell...
Click to expand...

I believe the Uponor Aquapex is particularly freeze resistant since it's designed to be expanded over the fittings. It's a lot more resilient than some other stuff I tried.
 
Noth Jersey said:
I believe the Uponor Aquapex is particularly freeze resistant since it's designed to be expanded over the fittings. It's a lot more resilient than some other stuff I tried.
Click to expand...

No!
Uponor PEX did experience splits in the test when fittings were 2-7" apart.
 
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