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What size hole

Bob Forand
Bob Forand Member Posts: 305
What size hole do you drill to run pex to baseboard? Do you use anything in the hole for noise ?


  • bob young
    bob young Member Posts: 2,177
    pipe vs. pex

    pex is for radiant . copper or steel pipe for baseboard. use correct size hole saw . leave room for expansion & contraction movement
  • nathan_8
    nathan_8 Member Posts: 8
    Pex is for everything these days

    You can run the pex to the baseboard as long as you operate the water temp within the specs of the pex. most I've seen say they will take 180F all day long. As far as the hole size to drill in the floor for the baseboard stub outs we use a 2" hole and use pipe insulation around the pex or copper pipe. If you do use pex note you will have to support it well as it really grows at high temps but is great for retro fits.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    I wouldn't

    use anything but a PEX-AL-PEX product like Viega's Fostapex or Uponor's MultiCor for high temp bb runs. Single layer pex will grow too much, giving you expansion problems like noise, chafing, and binding.

    I generally drill a 1 3/8- 1 1/2 hole and use Mickey Mouse ear clamps as bushings where appropriate. You want nothing too tight..
  • Bob Forand
    Bob Forand Member Posts: 305
    I have in the past

    I have in the past used Rehau he-pex for baseboard. I have drilled an 1-1/8" hole and just ran the pipe. I have had a couple of jobs where I can hear the pex making ticking sounds and I believe it to be where I ran it through the joists. I also believe that the Rehau product is also part of that problem. I am now using Wirsbo.

    That is why I am asking about the hole size and whether anything is used in that hole. If I drill a larger diameter hole with no hanger in it will that help the ticking sound go away ? I have seen the isolation hangers that say drill an 1-3/8" hole and ust them in the hole. Will those work or make it worse for the sounds ?
  • Chris S
    Chris S Member Posts: 177
    baseboard holes

    We use the plastic insulators in the hole, with pex, or copper- installed from the underside. We used to drill oversized holes and use armorflex, but inspectors are looking for fire caulk on all penetrations. By putting the insulators in from below, we can fire caulk from the top. Plastic on plastic, or plastic on the copper- no expansion noise. ODR will cut down graetly on expansion nosies as was previously stated.
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    You still

    risk noise unless you use a composite pipe. Uponor's EVOH barrier can even screech on plastic hangers. The rate of expansion is ludicrous when running high temps. I have even seen bb element lifted off the supports for want of regular pex looking for a place to grow. Do yourself a favor and use PAP for your bb loops. The expansion rate is similar to copper.

    Did you read my previous post on PAP and hole sizes?
  • Justin F.
    Justin F. Member Posts: 1

    have you tried drilling like a regular one inch hole and use the 3/4 mickey mouse suspenion clamps. just spred the top out a little bit to allow a little movement?? just an idea i had. some peopl tell me the insulators work but still make noise cause there so tight.
  • bill garnett_2
    bill garnett_2 Member Posts: 21

    If noise caused you a problem before the I would use something that does not expand and contract, pex aluminum is a good alternative as well as onix. Both those will keep the expansion noises to a minimum
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