cpvc vs copper

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by alhurley, Oct 3, 2005.

  1. alhurley

    alhurley Guest

    ok, I'm sure it's been asked, but my search didn't turn up much so I'll risk repeat.

    we're remodeling and currently rebuilding the master bath/shower. It's down to studs (actually, some of those came out) and now I'm rebuilding. House is 70s slab in AZ, and plumbing is copper. Supplies (3/4") run through slab and then through walls for baths. For various reasons, I've removed all the plumbing down to the supplies coming out of the slab.

    So I'm at Homer's picking up new copper and fittings and some guy asks me why I'm doing copper and not CPVC. "uhh - I dunno; cuz that's what's there already?" he didn't think that was a very good reason, and now I'm wondering. :confused:

    so the question - why shouldn't I just install the adapters and plumb out the bath/shower with CPVC? I'm pretty decent with a torch, but I know plastic is still easier. I also know everybody has their preferences.

    any thoughts out there??
  2. Master Plumber Mark

    Master Plumber Mark Master Plumber

    Feb 6, 2005
    Sensitivity trainer.. plumber of mens souls
    indianapolis indiana - land of the free, home of
    copper is better

    their is nothig wrong with the
    copper that is already in your home right??

    the cpvc is ok but it seems to get brittle where you
    you install or adapt to the faucets or to the copper....over time..

    its ok, but not as solid or durable as the copper

    both will work, cpvc is more for the amatures who know
    just barely how to open a can of glue..
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  4. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    Depending on where you are in AZ, if you put in CPVC, since it will be in the attic, you can forget about ever having "cold" water again. If you were in Scottsdale, you would have a CPVC fire sprinkler system in the attic, and you might also have periodical leaks when a fitting or connection broke.
  5. Gary Slusser

    Gary Slusser That's all folks!

    Aug 31, 2004
    Wherever I park the motorhome.
    PEX is probably best overall.

    You should add PEX into the mix.

    Quality Water Associates
  6. alhurley

    alhurley Guest

    thanks all for the quick responses. good data and pretty much confirmed what I was doing.

    not going to do Pex - doesn't make sense since I can't get the benifits of the central distribution and all.

    There's reall nothing "wrong" with the current copper - as far as I know. The supplies to the baths and kitchen are all in the slab - no water lines in the attic. The supplies emerge from the slab somewhere near the point of use and then copper - looks like flex tubing - through walls to fixtures. If there's an issue it's what I might consider sloppy layout. But it seems to work. (we've lived in the house 3 yrs)

    One example of the layout is in the bath I'm remodeling. They had the vanity drain and the water supplies coming out of the wall very close together - picture a 6" circle with all 3 lumped inside. Impossible to work with. Gone.

    I'm also completely reconfiguring the shower as I rebuild it - not just new control but body sprays, handheld, and rain head. Oh, and I needed to move the toilet supply outboard to work with a skirted Toto toilet.

    So the old bath plumbing just didn't work in the new design. But we're not replumbing the house - just on an 'as-needed' basis as we get to those rooms that have plumbing.

    so I'm sticking with the copper (pipe, not tubing) as planned. (been there, done that with the glue thing). Thanks for helping confirm! :D
  7. alhurley

    alhurley Guest

    the quality of copper?

    ok - slight shift of discussion but I'll keep it here unless it gets ignored. :D

    dug out my torches and solder tools and went to work. Now I admit it's been a while but my joints were looking terrible, and didn't inspire much confidence. (Just for reference, the last little DIY job I did was good enough my plumber friend told me it was better than a lot of the "pro" stuff he runs across.)

    Not willing to believe I'd completely lost it, I took a closer look. That's when I started recalling that back then the fittings all seemed to have a much tighter dry fit than the stuff I'm using now. In some cases, the fitting/pipe connection seems downright sloppy. At any rate, things seem much looser than I recall. That, of course, means it takes more solder - but solder is really not designed to work as a "gap filler," right?

    Am I imagining things here? Am I correct in my concern for getting good connections? How do you pros handle this stuff? :confused:

    (cpvc is starting to look a lot better...)

  8. slb

    slb New Member

    Jun 17, 2005
    San Francisco North Bay
    I'm not a pro, but one thing that has changed (at least here in California) is the flux. The new water soluable fluxes don't work nearly as well as the stuff that was available just a few years ago. The new fluxes seem to scorch much easier, so it's important not to overheat the joint.

    I still have a small jar of the "good stuff" that I use for difficult repairs.

    Good luck,
  9. alhurley

    alhurley Guest

    flux, eh? guess I better dig through my trash - I did in fact buy some of the new stuff to replace the old. guess I assumed "new technology" might be an improvement. DUH! :eek:

    sounds like sloppy fit and bad flux is a bad combo. :(
  10. alhurley

    alhurley Guest


    brief update - old flux = good joints. :D

    fortunately I haven't emptied the trash barrel in my work area recently and was able to retrieve the old tin. Also switched to Mapp for some of the connections - like Ts where I did more than one at a time.

    At 3 am this morning I turned the water back on and so far everything seems to be holding. and we're talking a LOT of connections! :eek: (being a remodel, even a small bath has a lot of interferences to deal with - ugh!)

    thanks for all the support! :)

  11. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Nov 8, 2005
    Hansville, Washington
    Flow in CPVC vs copper

    I'm looking at replumbing from under-slab to overhead in conjunction with a major remodel. Local plumbers favor CPVC over copper, but I'm wondering how the water gets through those tiny pipes? Looks like "half-inch" in copper refers to ID, but in CPVC it's OD? In any event the inside cross-section looks to be only about 60% of copper.
  12. Gary Swart

    Gary Swart In the Trades

    Sep 1, 2004
    Yakima WA
    You've got the idea. 1/2" cpvc is much smaller than 1/2 copper, and if you do your math, you can figure how much less volume the cpvc has than copper. Stay with copper.
  13. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Nov 8, 2005
    Hansville, Washington
    1/2" CPVC vs 1/2" copper

    Now I'm really confused. I posted previously based on eyeballing the CPVC I bought yesterday, but just now read the FlowGuard Gold Design document (http://www.flowguardgold.com/designinstallation/pdfs/FGGdesign.pdf), which claims an OD of .625 and an ID of 0.489 for the 1/2" FGG -- i.e., pretty-much the same as copper. I'll have to actually measure the stuff, I guess, but it sure didn't look right.
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