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Copper pipe encased in cement

Post in 'DIY and General non-hearth advice' started by hemlock, Aug 30, 2011.

  1. hemlock

    hemlock Feeling the Heat

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    Hello,
    This weekend I am going to pour some cement into a small "well" in my in-laws house where currently water leaks into the house pretty severly at times. It is where the service entrance for the water main is. Where the water main enters the house, it was never sealed properly. My question is - cement can cause copper pipe to corrode, so what would be a good product to wrap the pipe in before pouring the cement? At work, we have a product called "Tapecoat", which is used for pipeline corrosion protection below grade. Would this work on a copper potable water line? Thanks.

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  2. semipro

    semipro Minister of Fire

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  3. EatenByLimestone

    EatenByLimestone Minister of Fire

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    Gas lines have to be run through PVC when going though the basement wall here. It probably wouldn't be a bad choice for copper either. Caulk or foam could take up the space between the copper and PVC.

    Matt
  4. Dune

    Dune Minister of Fire

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    We don't run copper through the foundation anymore, it comes in plastic and then converts to copper inside. The plastic also gets sleeved with pvc.

    I suggest you use hydraulic cement instead of concrete if it is a water issue.
  5. yooperdave

    yooperdave Minister of Fire

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    what about good ol' pvc electrical tape?? just double lap it - kinda like the way you wrapped the baseball bat when you were a kid.
    have to do that for black iron gas pipe when it goes through walls...
  6. btuser

    btuser Minister of Fire

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    A copper water main is type k copper. About as thick-walled as you can get and should last a long, long time even if in direct contact with concrete/hydraulic cement. That being said it won't outlast plastic. I alway sleeve my penetrations when going through concrete/cement and seal with an expanding silicone, maybe foam above grade. Metal expands/contracts a lot, and when its pinched in place it will fatigue. Most failures are from movement, not corrosion. Hydraulic cement is the best for the exterior of the sleeve (if you can't pour it in place) I'm sure a coating on the pipe would belay my worries, some type of wrap designed for such would be sweet.
  7. semipro

    semipro Minister of Fire

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    From the link I cited above:

    "In spite of numerous myths regarding the acceptability of copper in contact with concrete, it is completely acceptable to bury/embed both hard drawn and annealed copper water tube in concrete. Decades of satisfactory service experience with the use of copper tube for in-floor radiant heating systems, water distribution systems and snow melting systems attest to the compatibility of copper tube embedded, encased or in contact with concrete. It is also acceptable to run a copper water tube through a concrete floor or wall, provided that allowance is made for the lateral thermal expansion and movement of the tube and protection of the tube from abrasion. This can be done by insulating the tube where it passes through the wall or by wrapping the tube with an approved tape (to avoid abrasion) and installing it through a sleeve. Please refer to your local plumbing code for specific requirements regarding the protection of pipes and tubes passing through concrete and masonry floors and walls. Both of the protection methods outlined above and the requirements listed in most plumbing codes are simply to protect the copper tube from the fatigue and wear caused by thermal expansion and movement. These protective measures are in no way dictated by the interaction of the concrete and the copper tube. Also, the interaction of copper with either dry and wet concrete should not cause a corrosion concern. However, copper should be protected when it comes in contact with concrete mixtures that contain components high in sulfur, such as cinders and fly-ash, which can create an acid that is highly corrosive to most metals including copper. One of the most prevalent myths regarding the use of copper in concrete is that lime in the concrete will have a negative or corrosive effect on the surface of the copper. In fact, a screened soil/pulverized limestone mixture is actually recommended as a selective backfill for copper tube to help eliminate corrosion concerns. There should be no concern regarding the interaction of the copper with lime in the concrete."
  8. nate379

    nate379 Guest

    Never heard of the corrosion thing, but my water main has foam around it. My folks have nothing and it was put there around 1962... so must be some SLOW corrosion.
  9. pen

    pen There are some who call me...mod. Staff Member

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    My only concern is that link comes from copper.org. Do they have a vested interest in what they are giving out as info? I don't know other than copper prices are high, pex tubing is being installed like crazy instead, and maybe they are scraping for business? Just wondering.

    My other question is how do you know the concrete coming to your house has a high sulfur content? Is there a test? Will the company let you reject the load if you find it is high?

    All I know is I have a house built in 64 w/ in floor heat in the concrete floor basement which is copper tubing. The floor is in good shape (no cracks) but if you turn that water on you won't hear the pump shut off (no holes, or changes to this floor either). Something made for some leaks here.

    I can't blame the concrete as I'm not willing to tear the entire floor up carefully enough to inspect but all I know is I'd do whatever I could to be sure that I was putting in a system that would be as guaranteed for as long as possible and with what I've seen, I don't think I'd be using copper.

    Just for some FYI, I'm not a pro-plumber by any means but I can sweat pipes. After doing a job nothing feels more rewarding than looking at a nice copper job. I don't care how careful you are w/ pex or pvc, it just doesn't look or feel the same.

    Point is, I'm biased towards copper but I have my doubts.

    The other problem is your own water. If that is acidic or perhaps even has a high sulfur content as is common, it will eat the pipes as well, even if the concrete does not.

    pen
  10. fbelec

    fbelec Minister of Fire

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    i would insulate that copper some how some way. see if there is some sort of adhesive or something on that idea that you could pour on the pipe and not bother the copper. then backfill and cement. in my town we have a section with these houses that are on a slab. no basements. a very big section of town. and lots scattered around this town and the next. all have copper in floor heating and one by one they are failing. i wire the boilers that windup replacing the original system some went bad in twenty years and some up to now 30. but they are failing. water lines to the house fail as quick also. so i find that hard to believe that cement doesn't take out the copper. i can see if it were the moving of the slab for the water lines, but the in floor heat moves with the slab and boiler sitting on top so that shouldn't be a issue, but the radiant is still failing.

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