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Supporting Vertical PEX on a re-pipe

Big-Al_2 Member Posts: 263
The specifications for PEX say that in a vertical run, it needs to be supported at each floor, and every four feet or less in between.  In a re-pipe situation, this might  mean opening up a lot of walls.  I just fished a couple of lengths of 3/4" PEX from a basement up to a second floor bath . . . up through a wall (alongside an existing PVC soil pipe) and a couple of feet sideways under a floor, and then elbowed up behind the upstairs  lav. The natural curl of the  tube seems to hold it  in place very well without ANY supports. I can fasten it top and bottom . . . , but  . . . in between, I would have to tear open a ceramic tiled wall in a kitchen or a bathroom.  I don't want to. 

Not having any prior experience, I'd tend to want to do it "by the book."  But . . . What do pros do in a situation like this?  Fasten it top and bottom and hope for the best?  I could see a big problem in a multi-story building, but this is only passing through one floor.


  • hot_rod
    hot_rod Member Posts: 21,868
    I fished

    across my office ceiling with pex. Every time someone shuts off the sink faucet quickly the pipe jumps and bangs.

    Slip some pipe insulation around it to soften the noise if it is not fastened as per requirement.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • EricAune
    EricAune Member Posts: 432

    You are probably up against some water hammer noise at most.  I have used the insulation trick and it seems to help.  Some situations just don't warrant cutting that sheetrock.  
    "If you don't like change, your going to like irrelevance even less"
  • Big-Al_2
    Big-Al_2 Member Posts: 263
    edited November 2009
    It has water in it.

    Thanks for the responses!

    I've been using the upstairs bathroom and haven't heard any unusual noise from the supply pipes.  They were run in a fairly narrow space between a 4" soil pipe and a stud, and the PEX had quite a curl to it, so It probably isn't exactly free to flop around in there. I was wondering why the PEX needed so much support, and I didn't think about the noise.   I was mainly concerned that the PEX might eventually have "saggage" issues from hanging by its own weight . . . but it's pretty stiff, so that's probably not going to happen.  I think it will be fine. 
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