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Radiant Heat Question

Fellow Wallies, in my nearly 30 years, I have never used any radiant heating, all baseboard & Rads! Anyway, I am currently remodeling my own bathroom. Today I finished jackhammering out the tile floor and 3" of mortar that they used for a base, 1920's vintage. I plan to reinstall ceramic later. I would like to put in radiant heat. Is it possible to install that plywood that is pre-grooved for the pex tubing, the type they use under hardwood floors. But instead of hardwood flooring, install cement board, then my ceramic tile over that? Has anyone ever done or seen this done? Any other ideas?


  • Mark Hunt
    Mark Hunt Member Posts: 4,909
    That'll work

    Are you planning on bringing the floor back to its original height?

    Mark H

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  • Brad White_95
    Brad White_95 Member Posts: 10
    I'm with Mark

    Entirely possible and good for you for seizing the opportunity!

    For my own bathroom I removed a mud job (and gutted the entire second floor to the studs so that the bathroom job would not seem so bad :)

    Took the sub-floor right off to the joists then insulated between them.

    On top of the joists I installed two layers of 3/4" T&G plywood, rosin paper, Stadler (now Viega) climate panels, screwed down tight.

    After laying the tubing in silicone and testing it, another layer of thinset then 3/8" wonderboard, screwed down tight. Finished with ceramic mosaic tile in thinset and grout. Done. Easy to match the floor height given the multiple thin layers you are working with.

  • amhwrite_2
    amhwrite_2 Member Posts: 4
    Radiant Heat Follow-up

    Mark, Brad and fellow Wallies, sorry about not responding sooner, its been a busy summer and I just got some free time to get back on my bathroom project! My wife and son are a little happier that I'm back on it too, two flights to the basement bathroom! I have my sizing done and am nearly ready for the floor. Anyway, some more brain picking if I could! From the top of my existing joists, I have 1-1/2 inches to match up with the existing floor out in the hallway. Even though the mud and tile was 3 inches thick, there was a makeshift subfloor between each joist about 1-1/2 inches below, very solid too! The joist above was recessed in the mud. The joists are only 2 x 10's, I wouldn't want to cut down any sized joists regardless, so some of my thoughts:

    1) Put two layers of 3/4" plywood on the existing sub-floor between the joists to bring it up even with the top of them, then a layer of 3/4" plywood, 1/2" cement board & ceramic tile. Could I get a router bit and groove the plywood for the Pex tubing or just get panels?

    2) Re-pour the floor with a lightweight concrete product, we are talking about an 8'6" x 9' area. I've poured areas this size in basements this size with regular concrete before. Can you reccomend a concrete product to use?

    3) Does anyone have any different ideas?

    Thanks all!
  • Wayco Wayne_2
    Wayco Wayne_2 Member Posts: 2,479
    If you are

    going to pour a lightweight concrete porduct make it easy on yourself and staple the pex on top of the plywood and just pour over it to the level you need. WW

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  • ChrisL
    ChrisL Member Posts: 121

    You might want to re-think adding two layers of 3/4 ply on top of the sleepers. I don't think it will add much. Screw and glue 3/4 ply on top of the joists, then staple pex and float a mud base, or use climate panel. It would be nice to get a total of 1" of wood floor down besides the tile, so maybe glue and screw 1/2" ply on top of the 3/4 if using a mud bed. You might be a 1/4" higher than the rest of the 2nd floor, but that is not a problem.

  • Tom Kane
    Tom Kane Member Posts: 56
    bathroom floors

    Try visiting Rehaus website and look at a product call Raupanel..........very high outputs and pretty easy to install.....
  • Michael_6
    Michael_6 Member Posts: 50

    Raupanel, then wonder board, then tile
This discussion has been closed.