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Radiant ceiling in plaster

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Over the years, I've seen a number of old radiant ceiling radiant systems.  Copper tube tied to metal lath and embedded in plaster.  Some of them are fifty years old and have been running 180* all that time and the plaster is still good.

I am now talking to a prospective customer about doing this.  Does anybody have sound advice and/or know sources of instruction on how best to do it?

Would appreciate any help you can give.

Bill Clinton

Comments

  • Wayne Heid
    Wayne Heid Member Posts: 49
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    I installed one last year

    Bill ... I designed and installed my first radiant ceiling last year about this time. It's a great way to go. I really don't understand why it's not done more often. You have much more flexibility with furniture and cabinet layout and you usually end up with a larger radiant panel with less thermal resistance. That means higher output for a given water temperature.



    We chose to sandwich the tubing between the drywall and a 1" layer of Dow Thermax Sheathing (polyisocyanurate foam w/ reflective facing) and insulate the ceiling joist cavities. This helped to minimize backloss.



    As far as sound advice, I'd take a look at Siggy's book Modern Hydronic Heating. There's a good discussion in Chapter 10 about Radiant Ceiling Panels.



    I have some photos of the install on my other computer. I'll try to upload them later this evening.



    Wayne
  • Wayne Heid
    Wayne Heid Member Posts: 49
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    Radiant Ceiling Photos

    Bill ... Here are the photos. This was a 700 +/- sq ft, 2-story addition. Family room on first floor and bedroom on second. The main portion of the house uses cast iron radiators.



    Wayne
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    edited October 2009
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    I did radiant ceilings, windows and radiant walls at my mountain home.

    Just fired it this last weekend, and it is toasty warm. I used Roth panel for the ceilings, and Wirsbo double track (flashing aluminum) for the walls. I'm running TRV's on the ceilings, and feeding 140 degrees F to the walls and ceilings, maintaining 95 to 100 degree F surface temps. Interestingly, the floor was running around 75 degrees, and it doesn't have any heat in it, just what it is absorbing from the ceiling.I too wonder why more people don't do radiant ceilings...The older systems running 180 degrees F water did make your head hot at times, but with proper controls, I don't think you would even notice WHERE the radiant energy is coming from.With as many tube and emitter choices as are available today, I wouldn't consider using copper in plaster though..Siggy does recommend putting half agin as much insulation in as would normally be necessary. So if you need R-30, then you'd want to place R-45 above a radiant heated ceiling.My walls were internal, and I insulated them with R-19, except near the bar, where I left the insulation out, causing it to be an omni-directional system. Keeps your knees warm when you are sitting a the bar.ME
    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.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
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    Radiant ceiling in Tatami Rm

    This Tatami Room has a radiant ceiling using the Wirsbo 14" wide transfer plates. The 6" bamboo floor mat (recessed in floor) made RFH out of the question. The owner loves the comfort.
  • NRT_Rob
    NRT_Rob Member Posts: 1,013
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    plateless?

    no plates wayne?



    what kind of water temps are you running, and what kind of heat load are you servicing?
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
  • Wayne Heid
    Wayne Heid Member Posts: 49
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    Yes, plateless, go figure ...

    Hi Rob ... Yes, I know what you're thinking. I was a little nervous going plateless. Our heat loss was 20 Btu/sq ft. at design. Water temp is 120* on a design day (0*). System is using OD reset.



    I modeled it using several different software applications both with and without plates. In every instance the numbers showed plateless would work. We insulated the bejeepers out of the back side.



    The real test though is if the client is happy. I stopped by yesterday for the annual service and the client says these are the most comfortable rooms in the house.



    Wayne
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    Is it noisy??

    Does it TICK TICK tick tick tick.... When it first starts up?



    Is it on ON/OFF zone valves or non electric thermostatic radiator valves?



    Just curious.



    ME
    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.
  • Wayne Heid
    Wayne Heid Member Posts: 49
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    It's very quiet

    Mark,



    There's no noise. The radiant circuit water temps are controlled by a Honeywell AQ2000 ODR with injection mixing. Most of the time it's operating much lower than the design temp.



    Wayne
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    Interesting...

    Thanks!



    ME
    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.
This discussion has been closed.