My thoughts for repiping:

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Pewterpower, Jun 29, 2006.

  1. Pewterpower

    Pewterpower New Member

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    I have a 2 story house, with copper pipes in the slab. I just repaired my second pinhole leak at the slab and I am not doing it again.......
    I want to repipe with pvc & cpvc.
    My water main comes into the house at the garage. What I am thinking about doing is cutting the main, right after the spigot, bring it thru the garage wall, and straight up to attic. In the attic that is over the garage, I can build a manifold, and pick up the hot water (the water heater is in the garage, so I can run a pipe back down to the tank, and then a pipe back up to the attic) so I can keep my hot and cold water pipes in close proximity of each other.
    From the attic I should be able to branch off and get to all the fixtures by dropping into the walls from above. The only problem I see is with the kitchen, since it is on the other side of the house, and there is no attic above it. Just a space large enough to contain the HVAC ducts, and insulation.
    I figure I have 2 options.......
    1. I can go under the driveway, along the side of the house, and then enter thru a kitchen wall. Or...
    2. From the attic, I can run pipes all the way thru that ceiling space and out the soffet. Then down the side (the outside) of the house, and come thru the kitchen wall.

    I'm trying not to overthink this too much........

    How's this for a first post??? :lol:

    http://www.terrylove.com/watersize.htm
    Last edited by a moderator: Jul 9, 2006
  2. Cass

    Cass Plumber

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    What part of the country are you from?
  3. Pewterpower

    Pewterpower New Member

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  4. Bob NH

    Bob NH In the Trades

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    Inside can be only CPVC; not PVC. I would stick with all 3/4", unless you find that you need bigger.

    You can run the pipe where most convenient. But you want to consider temperature variations in the attic and in hot water pipes. CPVC has a very high coefficient of expansion (Google for the numbers) and you will have temperature ranges of more than 100 F in the hot water line.

    It is very important to consider how things are going to expand when you install supports. You don't want a hard support right at the end of a long straight run where it will prevent expansion or contraction.

    You can probably get expansion joints but I prefer to deal with expansion by layout.

    You can take care of expansion and contraction by putting right angles in the runs, even if you don't need them. You have probably seen big U shapes in above ground pipelines. Those are to accommodate expansion and contraction.
  5. Gary Swart

    Gary Swart In the Trades

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    If you insist on CPVC, you need to be aware of that CPVC and copper pipe sizes do not compare. CPVC has a much smaller inside diameter than copper of the same size. In other words, 1/2" CPVC is more like 3/8" inside whereas copper is a true 1/2". This makes a huge difference on the volume of water the pipe can carry, so CPVC must be sized larger than copper. Running your pipes in the attic will mean you will never have even cool water in the cold pipes in the summer.
  6. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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    The kitchen problem

    I'm about 50 miles from you; I had the same problem, both leak and kitchen layout. I re-plumbed overhead with CPVC, but used a 3/4" manifold with 1/2" branches (individually valved). If I had it to do over again, I'd use 3/4 all the way, as Bob recommends.

    I solved the kitchen problem by bringing the pipes down an inside wall, then routed them under the lower cabinets' kick-space around to the sink. I put a false front on the kick-space, painted it black, and you can't see the difference. If some future owner decides to nail something to the kick panel he might get a surprise, but otherwise it's working fine.

    Cold water is warm at the end of the day, since it's spent the day in a 120 degree space, but that's why God made water-in-the-door refrigerators. Bob's caution re CPVC expansion is well taken. When the hot water warms up the pipes under the cabinets, you can hear them squeaking as they expand and slide in their channel in the woodwork. Someday maybe I'll take off the false front (it's not fastened permanently) and lube the pipes with something, but it's not bad enough to bother me right now.

    In the attic, the mainifold is about 80' long, which will expand about 3 1/4" over a 100 F degree temperature differential -- that needs to be taken into account when you lay out your pipes and position pipe hangers. I had to go around a chimney (roughly in the middle), so the big U in the line absorbs half of the expansion.
    Last edited: Jun 30, 2006
  7. toolaholic

    toolaholic General Contractor Carpenter

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    my 2 cents

    have you considered using pex?
  8. Pewterpower

    Pewterpower New Member

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    Some great points, guys.........thanks.
    Cold water that is never cold???? Nobody drinks the nasty tap water in Fla anyway. :lol:
    I've never worked with PEX before, but I've done alot with PVC in and around my pool, so that's where my comfort level is.
    I will use CPVC throughout the house. Thanks for the expansion tips. (how do pipe hangers allow for expansion? or do you just not make them tight?)
    I plan on using 3/4 all the way.
    This site is awesome.........thanks, again.
  9. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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    Sloppy hangers

    (how do pipe hangers allow for expansion? or do you just not make them tight?)

    I just used the hangers I found at HD or Lowe's -- the pipe can slide through them easily. When I first started installing them, I wondered why they were such a sloppy fit. Now I know. In one Website that discusses the expansion issue, they make a distinction between hangers that are "guides" and those that are "restraints". It looks like the big-box hangers are all "guides".

    http://www.corzancpvc.com/designSpecInstallation/thermalExpansion.asp
  10. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

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    When I was in India, the cold water was so warm you would have no problem forgetting to turn the hot water heater on! You could save some money by putting the water heater in the attic. :) Or at least a lot of pipeing to it--zig zag.

    I'd imagine that warm-cold water would be better than cool-hot water. You spend most of your money in warming cold water, not cooling the water. You through some ice in the water if you want it cold, or keep it in the fridge.

    Jason
  11. Pewterpower

    Pewterpower New Member

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    My thoughts exactly.
    I have a solar power water heater, so there is no money spent on elect there. And nobody drinks the cold water anyway, we get it from the door in the fridge.
    If I wanted to keep the cold water pipes cooler, though, is there a trick to doing it? I've read that insulation is a waste of time.........
  12. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

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    Trick? No not really...don't plumb it where it will get it hot, or put in an inline water chiller. If you put them underground, they'll stay cool too.

    http://www.anaheimmfg.com/products/coolwater/coolwater.htm
    http://www.aqualogicinc.com/chillers/indust.htm
    http://www.air-water-nutrition-healthsmart.com/open/C-Chiller.html


    I'm actually in the market--once the kitchen remodel is done--for a chiller for my aquarium (120G Saltwater FOWLR). It's similiar to what you could use, but much lower temp drop and lower flow.

    Jason
  13. Pewterpower

    Pewterpower New Member

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    main line that enters the house...

    When coming off of the main, how soon do I need to bring the pipe "inside" the house?
    Another option I am considering is running the main pipe up the side of the house, all the way to the 2nd floor attic, and then entering the house. I wouldn't leave the pipe exposed, of course, I would protect it with that flashing/guard/channel stuff that you see the AC lines in. Would CPVC be OK for this type of application, or should I use copper just for the "outside" portion?
  14. Pewterpower

    Pewterpower New Member

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    I just found this website http://www.toolbase.org/techinv/techDetails.aspx?technologyID=296 that has some very helpful videos. This stuff seems to be pretty easy to work with. I need to look further into the costs of the materials, tools, fittings, manifolds, etc........
  15. Bob NH

    Bob NH In the Trades

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    When you select PEX you need to consider the ID, even more than with CPVC.

    Regarding supports:
    1. When changing directions to go through a hole of any kind, the hole doesn't move and you need to leave some place in that line to accommodate the change in length.

    2. Don't clamp a pipe just after you turn a corner from a long run, unless you have planned to accommodate all of the expansion somewhere else in the line.

    3. A wire hanger makes a good support in an attic because it accommodates motion in all directions except down, which is where you want support.

    4. If you can install a running board in the attic to lay the pipe on, that makes a good support.
  16. Pewterpower

    Pewterpower New Member

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    Anyone have an opinion on this?
  17. Pewterpower

    Pewterpower New Member

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    OK, I think I've made up my mind.....

    I think I will connect to the main with copper, and run it up the side of the house into the 2nd story attic. I already have pipes there from when my AC and air handler was replaced, so I can run the pipe up thru the same flashing all the way to the roof.
    Secondly, I've decided on PEX. After a visit to the Orange box store, I had decided PEX was not worth it. Thier section was not impressive. The tubing itself was inexpensive, but the fittings, and especially the crimper, were way overpriced. Actually, thier PEX section looked more like a "Just in case anybody needs any of this stuff, we have it right here" kind of section.
    For the heck of it, I went to the Blue box store. There PEX section is HUGE!! Well laid out and very impressive. They had all kinds of tubing, red, white and blue, every fitting you can imagine, and "contractor's packs" of the more popular stuff. The crimping tool was way cheaper, and they even had a few manifolds.
    So PEX it is!!!
  18. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

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    I'm not a big fan of PEX, but that's just me. When properly installed, there is no reason why it can not be a great system and last a long time. Make sure, though, that you do not have any rubbing of pipe against anything abrasive and that you allow for expansion movement...hmm that sounds kind of tough, no?

    I've had a bad experience with it. In my old apartment, which was built over a crawlspace, they had used pex. They just busted holes in the walls (near water heater, under sink cabinets, tub, etc) and snaked it through. I ended up having a leak where it was rubbing against the old copper pipe they had cut off. Of course this pinhole leak was there for years.

    Water hammer caused a lot of movement and I'm sure thermal expansion would too. This is just something to look out for. Properly installed, I'm sure it would be a great system.

    Look online for a crimper. I'm sure someone can recommend one, and I bet it's cheaper than the Blue and Orange box stores.

    Jason
  19. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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  20. Pewterpower

    Pewterpower New Member

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    I wouldn't be so hasty as to just jab this stuff thru a wall. :) I would definately soften up any opening, or at least protect the pipe somehow.
    Expansion doesn't seem to bee too much of an issue, just because of the very nature of the installation. It seems to be loosely hang, or fastened, and it's not very rigid to begin with.
    I checked several websites, and even on ****, and prices all seem to be inline with what I saw at the Blue box store. The one thing that I don't want to go cheap on is the crimper. I think I'll stick to a store bought one.
    I'll probably start gathering materials in afew weeks and do it whenever.

    In the meantime, I'm still undecided as to what kind of pipe I can use on the outside of the house. I'm pretty sure what's out there now is 1" PVC.
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