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Recommendation request: copper vs pex for new plumbing with existing copper

Recommendation request: copper vs pex for new plumbing with existing copper

Old 12-21-17, 02:16 PM
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Recommendation request: copper vs pex for new plumbing with existing copper

Hello all,

I'm (finally) getting to the plumbing portion of my basement finishing project. This will be my first time working at all with plumbing supply. I'm adding a full bath and a wet bar (so two sinks, shower, toilet for total fixtures).

The existing supply lines are all copper and I've had no leaks or other problems (aside from some banging). Conveniently the lines run behind the wall of the new bathroom before going to the kitchen, laundry, and baths on upper levels.
I was initially assuming I'd just make a couple cuts to T out for the new bathroom and a second for the bar sink. I've done some light electrical soldering and am reasonably confident in my ability, though I am a bit leery if I'd have trouble fitting the cut copper to adapters when it is already rigidly in place.
Since I've started researching I'm hearing that PEX is apparently the best thing ever to happen to plumbing and am leaning toward that instead.

It sounds like it wouldn't be hard to cut out a small section of the hot/cold, put in a small length of pex with adapters on either end, then make additional Ts and runs for the new fixtures.

However, the manifold approach seems very appealing without too much extra effort. I could cut out the entire length of copper and just leave what goes up to the upper floors... then set up a manifold with an adapter to the copper for the existing rooms/fixtures.

What I do NOT intend to do is a full retrofit and replace the plumbing on the upper floors.

So I feel like I have a pretty decent idea of what each approach would entail and am just looking for some opinions. What would you do if this were your house and you weren't on an extremely tight budget (but enough that you didn't want to hire a professional!). Do you think I shouldn't fix what isn't broke? Is it worth building in a manifold? Is PEX overrated and should I stick with copper to copper?

Thanks for all opinions and expertise!
Old 12-21-17, 02:27 PM
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I'm an old fart and completely comfortable with soldering copper piping so I used copper for my remodeling. However, PEX is a very good product PROVIDED you keep it away from ultraviolet light. That means sunlight and full-spectrum fluorescents. PEX is VERY easy to work with and its flexibility often means you can get by with fewer fittings. It is also significantly less expensive than copper.

I would not advise replacing any of the existing copper as long as it is serviceable. I would add ball-type shut-off valves at the tie-in to the copper and then transition to the PEX. Also use copper "stub-outs" with brackets to hold the stub securely to the wall or stud where you will located the shut-off for the individual sink, toilet and shower valves.

Others may have different ideas.
Old 12-21-17, 02:54 PM
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Old fart II,

I know nothing about PEX but in my opinion I'm never going to put plastic water lines in any house, remodel, or repair that I complete.

Cost is not a consideration since I'm doing the work so who cares if the fittings are a few extra $.

Soldering is a piece of cake as long as you clean the fitting/pipe till it shines, use clean flux, clean acid brushes, and clean solder it's almost fool proof.

Take a short cut then you will have problems.
Old 12-22-17, 10:08 AM
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If I were doing your project, I would use copper fittings to tee off the existing copper, and convert to PEX at that point for all the new runs.

More importantly, you should be teeing off a 3/4" pipe and not a 1/2" pipe going to a specific fixture group.

I'd agree with Furd in using copper stub-outs. Having PEX pipe flopping around in a cabinet is code-compliant, but bugs the heck out of me
Old 12-22-17, 03:26 PM
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Since you are in Wisconsin I would definetely go with PEX. It withstands freezing quite well.
Old 12-22-17, 07:36 PM
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Thanks for all the tips! At this point I think I'll Tee out to Pex with a small manifold for all the new work... leaving enough space to add additional lines if anything needs to be replaced later. Otherwise I'll leave the rest of the copper untouched.

I'm kind of surprised that I'm not finding a lot of the parts at the local big-box stores, but it shouldn't delay me too much.

I ended up buying the copper stub-outs that didn't have the integrated flange figuring I'll just clamp it myself... they tended to be significantly more expensive. Hopefully that wasn't a mistake!

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