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tube material

Chris_51Chris_51 Member Posts: 24
I'm working on my 3rd radiant floor.  I'm not a contractor, but have one.

One one back in 2001, we pulled the water from a radiator feed that we disabled.  There was some discussion whether the boiler water would be sufficient as a source.  It worked out well and has been turn key for years.  We have an old house with a converted gravity system in a single pipe configuration.  So no zones, just water temp adjustment on the logic.  I just leave the radiant floor pump on all the time, and did a one time adjustment to the 3 way mixer. 

I wanted to do the same thing on a bathroom remodel we are starting in a week or so.

The local supplier is pretty good.  He does a parts list and builds a quick diagram.

In the original 2 floors we used rubberized pipe.  For this job, he sent hard plastic pipe.  The brand was Roth.  This material seems harder to bend to a tight radius.  In a test, it bent further than I expected, but did kink over before getting as tight as I hoped for.  I think its workable though.

So is this material as good as the rubber?  Its been a while since I've done one of these.  The contractor asked whether this is an improvement?  The rubber products has lasted, so I'd rather stick with what I know if its all just a preference.

Any thoughts?


  • SWEISWEI Member Posts: 7,356
    Pipe options

    Your previous tubing was probably some kind of EPDM sandwich design - do you happen to know the brand or trade name?  Not all of those are 100% reliable and it would be good to verify this before you get too far into a remodel.  There are strategies for dealing with them, but you really should know what you have there.

    Pretty sure Roth is PEX C.  You might look at PEX A, which is more flexible and can be de-kinked with a heat gun, unlike the other types.  It's available from Uponor, Mr. PEX and Rehau in the US.
  • Chris_51Chris_51 Member Posts: 24

    The original was wattsheat was ONIX.  I think that was after the reliability issues of rubber type tunes.  It held up.

    Is this more rigid stuff workable and reliable?  If they can install it, then OK. 

    I was planning 1.5 inches of cement encapsulating the tubes.  That works well in the kitchen.
  • SWEISWEI Member Posts: 7,356

    has its crosslinks oriented in a radial pattern (versus the random orientation of PEX-B and PEX-C.)  This results in both increased flexibility and better burst resistance.
  • Chris_51Chris_51 Member Posts: 24

    I'm not sure where this leaves me.  I'm reluctant to use aproduct that clearly doesn't bend easily.  
  • SWEISWEI Member Posts: 7,356

    about what exactly you're asking.  I'll recap:

    I would choose PEX-A over the other options. PEX-B and PEX-C do not bend as easily and in the event of a kink you will need to cut and splice using a coupler.
  • Chris_51Chris_51 Member Posts: 24

    Since i have two floors with ONIX, and ONIX is easier to install, I guess I'm wondering why I'd switch.  I agree the particular type of PEX you mention make sense, but its still a tougher install.  ONIX is EPDM.  I did some searching and see a few complaints.  Most seem to be under floor staple up jobs though.  This is a slab.  I've had good luck with the two slabs I have, at least as far as leaks.  Basically no leaks.  I'm not sure on the leaching people discuss.

    My installer doesn't have a lot of experience.  He is doing this one based on my assurances that its easy and reliable.  So I guess my question is do I really want to go to an unfamiliar material. 
  • SWEISWEI Member Posts: 7,356
    Onix tubing

    I'm going to defer to some of the others here who have recent experience and can offer meaningful advice.  I know the newer variants are supposed to be better, but I don't any recent experience.  You should find out for sure which generation was used for the previous work.

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