Plumbing new building, questions on PEX

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Jasong71, May 23, 2013.

  1. Jasong71

    Jasong71 New Member

    Messages:
    5
    Location:
    New Hampshire
    Hi,

    So I am an advanced DIY'er. I am renovated an older, 2-story gambrel building on my property. We are moving our daycare/preschool out to it. I have it down to the studs and will be insulating the entire first floor and adding a bathroom with 3 toilets in a straight line and 6 sinks total. Furthest distance between 2 sinks is about 20 feet.

    We are putting in a new septic and a drilled well. The well will go 150' to the house and then back 75' to the building. What considerations do i need to make for plumbing the fixtures.

    Also, it is sitting on posts on concrete footings, so there is no slab or basement. I am in the northeast and winter is cold. Would a box around the plumbing filled with expanding foam be enough to insulate the plumbing so it does not freeze? or is there a better way to do this?

    Thanks!
  2. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    No insulation creates heat and no matter how much of it you use without a heat source the pipes will freeze.
  3. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,387
    Location:
    Yakima WA
    I'm not a pro, but I have often wondered why when folks build a building that will have long hot water runs they do not put in a recirculation system so even the far units will have virtual instant hot water. I would certainly not use PEX when the walls are open and copper can be run without undue effort. but that my personal bias. I would suggest you make sure your pull all of the permits required and follow all build codes to the letter since this will be a commercial building and children will be involved in the use. There are many places you can err on these matters, so DIY may not be your smartest move.
  4. Jasong71

    Jasong71 New Member

    Messages:
    5
    Location:
    New Hampshire
    The expanding foam insulated box is the norm for up here and it does work. It can get to 20 below zero. I am not opposed to heat taping it either. Is there better option?
    Last edited: May 23, 2013
  5. Jasong71

    Jasong71 New Member

    Messages:
    5
    Location:
    New Hampshire
    Gary, thanks for the input. The furthest sink from the water heater is 15'. I did not think that was a long run, am I wrong about that? Would a recirculator really be that much of an improvement?

    I hear PEX is great and most builders up here are using it. I am not opposed to copper since that is what my experience is in, but I am interested in the PEX.

    I have pulled my permit and there are no local building codes, so I am following the National ones.
  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,316
    Location:
    Bothell, Washington
    In my expierence repairing frozen pipes over the decades, unless you temper the heat around the pipes, they will freeze. Bundled pipes in foam at 10 degrees don't know they can't freeze, they do. When we install pipes, we try to trap the warm inside air to keep them above freezing. Sometimes insulating the all the way around prevents the warming they would have gotten if they had only been blanketed on one side.
    That being said, it's rare for a pipe in a crawlspace to freeze. The ground under a structure, as long as it's skirted keeps things warmer.
    It's common for pipes above the first floor to freeze in outside walls if the power goes out for a day or two.
    Putting pipes below the frost line also works.

    There is nothing wrong with PEX, and many are switching to it. I wish there had been more PEX run when I was younger. I don't think it's realy healthy to do much soldering.
  7. Jasong71

    Jasong71 New Member

    Messages:
    5
    Location:
    New Hampshire
    Thanks Gary...Pex looks a lot easier to install. Rather go that way.

    The building is skirted all around with a maximum distance from ground to siding of about 2 ". Wanted to keep some airflow so it doesn't get too moldy under there. Most of the installers I have been talking to were going to box the pipe and spray foam it. Could I leave a vent from the floor to the box that the pipes are in to help heat it? I will still insulate the walls of the box too.
  8. Terry

    Terry Administrator Staff Member

    Messages:
    15,316
    Location:
    Bothell, Washington
    If air movement is within reason, it should be okay in the crawl.
    Around here, you would skirt down to the ground, and then add ventilation.
  9. Jasong71

    Jasong71 New Member

    Messages:
    5
    Location:
    New Hampshire
    I keep hearing about an element that can be submerged into the pipe to keep it at a constant temperature, but I can not find any info on it. Any idea's what it is and where to look for one? Thanks!
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