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In our new addition we plan to have hydronic radiant heat in large master bath. Our shower will be 5' x 7' with curbless entry. Is it possible to continue radiant heat in the shower? I am getting conflicting answers from other.s. Appreciate any info and help.


  • ZmanZman Posts: 3,339
    edited April 2014

    Yes you should heat the shower floor.

    How are your tubes being installed? Underfloor? Concrete slab? Thin slab on top?

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • GordyGordy Posts: 6,795
    Radiant shower walls

    Along with the floor.....Cozy. You may not want to come out.
  • SWEISWEI Posts: 7,356

    heated shower walls are the bomb.  If the bathroom has outside walls, they're sometimes the only way to get enough BTUs into the space.  
  • GordyGordy Posts: 6,795
    Big showers

    Can be fun designing. Think shower seat with a little radiant touch for the tosh , niches for bath products, and a foot niche for the ladies about 12-15" up to shave their legs. Lots of possibilities.
  • Tim PotterTim Potter Posts: 207
    watch the ceiling

    Watching This Old House last nite, Tommy designed a shower with heated walls & floor. He was quick to point out a flat ceiling would condense and drip cold water on the person in the shower, the solution, why a slightly sloped ceiling so the drips would run to the the wall.

    Winter Park, CO & Lenexa, KS
  • RobGRobG Posts: 1,850

    As an added plus, it will dry the water before mildew will form.
  • GordyGordy Posts: 6,795
    Condensing ceiling

    Hmm never seen that sounds like an insulation issue. Would happen regardless of radiant surface presence.
  • NYplumberNYplumber Posts: 476

    Would be willing to bet the ventilation wasnt done correctly.
  • GordyGordy Posts: 6,795

    Forgot about that only because I just take for granted ventilation in a bath is done....and correctly.
  • added question (hopefully on topic) about PEX in wall

    i hope this is closely related enough to be of interest to OP, and not a hijack.

    For the radiant heat in the walls, how have people been installing: embedded tubing in traditional mud; or tubing in plates under cement board,(perpendicular or parallel to the studs); or ???
  • hot rodhot rod Posts: 6,710
    nail the plates

    onto the studs vertically. This keeps the tube away from where the nailing will be done, and puts the plate in good contact with the cement board. A large loop at top and you can have two plates on one stud.

    It takes some practice to install the tube into the plates if they are not tight against a floor, for example.

    Use nail plates if you need to run tube across the studs.

    Rare to se a full mudset set on residential walls, it's a lot more work and cost to do a leveled, square, plumb mudset.

    If you have a bench, add some heat to it also.

    Here is a shot of a radiant counter top in my bath.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • thanks and love the idea of counters too

    Thanks for tips. I was't too exited about mudding a wall. I am confident on getting it plumb and perpendicular, but it take me a long, long time and that's a lot of work. I am just a little worried about losing contact with the walls over time. Have you ever used any adhesive (plate to cement board)?

    I'll be doing a steam shower, so the wall heat actually reduces the size of the steamer i have to buy.
  • Mark EathertonMark Eatherton Posts: 5,552
    Human microwave steam sauna/shower.

    We did a job once on a 60K square foot home. The master bathroom had a steam sauna/shower that was 10' X 10' with a 10" ceiling. We did radiant floors, walls, ceilings and bench. We originally put the radiant on a twist timer and instructed the consumer to start the timer about 30 minutes before using it as a steam shower. It developed great vapor almost immediately on start of steamer. Didn't waste any steam heating the mass of tiles, terrazzo floors etc.

    The consumer liked it so well, they kept it on ALL the time. Only problem there was that huge mass of heated tile cause the surrounding area to be exceptionally warm, which wouldn't allow the rest of the bathroom floor to heat up because the stat was always satisfied.

    They were willing to live with cooler floors in the balance of the bathroom in trade for a nice toasty warm human microwave oven :-)

    Don't forget to insulate all cavities, regardless of wether it adjoins a heated space or not. Also, high density fiber glass insulation keeps the plates in good contact with the cement board, but YOU have to install it to make certain it does its job. Also, the use of adhesives is not recommended with radiant (VOC's and other issues).

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • hot rodhot rod Posts: 6,710
    Consider the Roth Panel

    system. It has a solid aluminum surface on a foam backer. It is grooved for the tube, ready to go. It would provide a solid wall to wall aluminum surface for the backer board to contact. Batts or foamboard behind that for good r.

    Don't forget a heated towel warmer, maybe a concrete "mans best friend"
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • RobGRobG Posts: 1,850
    Radiant Pup

    HR, didn't you use CSST in that dog? If so how is it holding up?

  • KC_JonesKC_Jones Posts: 3,079
    steam shower

    I saw the same episode it was a steam shower that had a steam generator plumbed into it and there was no direct ventilation other than a hinged transom above the door.  The vent fan was in the main part of the bathroom. That's why he had concern about dripping condensate.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • GordyGordy Posts: 6,795
    Muddled walls

    My showers were both muddled. I remodeled one if I had known how solid it was that's where I would have gone in a tornado. The only reason I remodeled it was I had to replace the shower valve.
  • good point on the VOCs

    i didn't think about the VOCs. i'm sure i could avoid them, but it would cost a LOT more. besides that, i worried about many adhesives being better insulators than conductors. It wan't easy finding much on the subject except for CPU cooling.

    I have two inches of extruded polystyrene (pink board) between basement wall and studs and another 2" between studs (foamed in cracks to keep tight). With the elevated temps and moisture i am trying to keep dew point someplace dry and towards the outside of the house.

    I may still use a little fiberglass, but just for that compression against the plates. Thanks for the idea.
  • What the heck is a concrete man's best friend?

    I like the tower warmer idea, however, I don't like the expense enough to buy one-- at least not one of the hydronic ones.

    i'll go check those panels. They might be a decent solution.
  • Mark EathertonMark Eatherton Posts: 5,552
    A concrete mans best friend is....

    A good set of rubber boots :-)

    The item HR is referring to is a concrete pointer dog statue with tubing run through it. It used to reside in his bathroom as a towel/space warmer, and was connected to his hydronic system.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • NYplumberNYplumber Posts: 476

    With all the good radiant wall talk, I can't help but ask about spray insulation.

    I'm installing radiant walls on the job we started. Plan to have the walls sprayed and then lay the plates into the walls horizontally after the foam is dried. Plates will be in contact with the foam, and sandwiched on the other side by the board screwed to the wall. Any issues that I am not aware of? No interest in doing it wrong the first time!
  • SWEISWEI Posts: 7,356
    Spray foam walls

    How are you going to get the plates to lie flush?  Usually this involves a router and some kind of guide or template.
  • NYplumberNYplumber Posts: 476
    soft foam

    Foam is soft, and the studs will be routed.
  • GordyGordy Posts: 6,795
    Hot rods approach

    I like going vertical keeping the tube off the studs except at alternating tops, and bottoms. Saves routering slots, and only drilling holes for tubes. Unless heatloss needs closer centers than stud layout allows which you could throw a plate on both sides of a stud. Cement board screws bad day!
  • NYplumberNYplumber Posts: 476
    horizontal vs vertical

    I was told that horizontal is better due to less of a chance of air getting trapped in the lines.
  • GordyGordy Posts: 6,795
    Trapped air

    Should not be a concern with proper flow rates. Is this shower muddled or cement board?
  • NYplumberNYplumber Posts: 476

    To be exact, its a bathtub with the floor and walls to be covered in tubing. Most likely going the horizontal route.
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