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concrete buried hot water piping

Kevin M_2
Kevin M_2 Member Posts: 2
Running a chase is a great idea, insulate the chase with foam insulation and install put a piece of foam board under the concrete to insulate it from the ground. Direct burial is qickest and cheapest. The suppliers in my area only have 1/2" foam so I double insulate to prevent warm spots in the concrete floor. Either way will work fine.


  • CHUCK_27
    CHUCK_27 Member Posts: 3
    Buried HWS piping in concrete

    I have a space with no ceiling, and I need to supply fintube on the far wall with hot water so i need to install the piping in the slab. If I use Pex pipe how and what kind of insulation do I use?
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Why not

    As long as you are doing that, why not run a buried length of PVC pipe with long-radius elbows, at least 2", maybe 3" or 4" if you can fit it, as a protective conduit.

    Into this you can pull/thread the PEX allowing future replacement or supplementation if you like. Nothing wrong with direct-buried of course, but it gives you some options and added protection. May allow you to pour your slab while you await the heating person.

    For insulation, Armaflex would be my choice, 3/4" thick.
  • hot_rod
    hot_rod Member Posts: 21,820
    I made a huge mistake a year ago

    by trying to put insulated pex in a pour. It was actually a favor for the plumber to supply his DHW. I wrapped two 3/4 pex lines in Armaflex, and installed them directly under the 6X6 wire mesh.

    They floated up big time! We noticied it starting as the pumped, in my opinion, too wet of a mix. We quickly bent some rebar hoops to hold it down.

    But later in the day when they put the big rider power trowels on the slab it vibrated even more tube up.

    An ugly expensive mistake on my part.

    I'd suggest they get buried in the gravel at least 6" below the remesh or bar.

    Check out www.insulseal.com. I use this for solar and outdoor piping. It's nice as Brad mentioned to have a condiut.

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • ALH_4
    ALH_4 Member Posts: 1,790

    I'm sure there is a reason, but I have to ask. If this is a new slab, why not put pex in the slab and have radiant floors?

    Running a 3/4" pex line in the slab for a thermostat wire conduit is also a good idea. If you bury the heat pipes directly in the slab, use electrical conduit bends to help keep the pex straight where it comes up out of the slab and to offer some protection once the slab is in place. Armaflex insulation is excellent.

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