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Ceiling Question

Cavallo Member Posts: 22
Preamble: I am only beginning to research this. I have not made any plans, nor purchased any materials or equipment as yet. I am asking this stuff because I don't honestly know. If my questions are dumb and noobish, I apologize in advance.


Hypothetical scenario. A house, 26x24ft, balloon construction, two stories, plus short basement and attic. Hip roof. Entire building envelope completely sealed with 2# closed cell foam, from the basement top periphery to the peak of the roof deck. Walls are expected to be R21, and roof R38. I have no square footages yet, so a proper heat load analysis has not been done. Imagine a standard complement of doors and windows. I'm not looking for hard numbers yet, just opinions.

Would it be outrageous to place aluminum spreaders and pex-al-pex with sleepers in contact with the first floor ceiling's sheet rock for top-down radiant on the first floor, and then neglect to insulate above it so that some of the heat warms the floor of the second floor, kind of like a staple-up, thereby heating both floors in one go?

I'm sure a ton of math would show whether this is reasonable. Before I go any further, I was wondering if anyone else may have done that math.

I realize that it would basically make the entire house one, giant zone, and this may not be wise, but ignore that for the moment.


  • Snowmelt
    Snowmelt Member Posts: 1,415
    edited May 2014

    I get your idea in simple theory and not looking at whole picture.

    The heat will go to the cold. Here's a small sample , you put pex I ceiling with no insulatition and you put up rock on the ceiling,

    The wood floor & subfloor would keep the heat from comming up, but just the sheet rock would be cold and the heat from the pex will come down.

    Unless I miss read what your asking,please ask again..?

    Maybe install insulation in between the tubing that's in the transfer plates and another set of tubing for your room below. You still would want to drill your holes separate you may need to run more loops. I know what your trying to do, I wouldn't do it, I would just take the ceiling off the basement and run tubing there with heat transfer plates.

    What the heat transfer plates allow you to do is run the water at a lower temperature. What you don't want to do is run the tubing and then you have to run the water temp at 180 degrees to keep the rooms warm.
  • Gordy
    Gordy Member Posts: 9,546
    edited May 2014
    Radiant ceilings

    Done all the time. A to often over looked radiant panel surface. I have them in my house love them.

    But dual purpose is going to have issues. One is control between the lower floor room with ceiling radian, and the upper room which will end up having a mediocre radiant floor.

    Depending on the loads of the two rooms which will unlikely be the same , and the radiant floor will not be as effective with tubing so far away from the floor assembly.

    What you will end up with since one of the rooms will be a control slave to the other is one over heating, and one under heating which will depend on thermostat location.

    So if the thermostat is in the radiant ceiling room the floor above will under heat.

    If the thermostat is in the upper room the radiant ceiling room will over heat.

    The only way to get effective control is to do staple up to the floor for above room. Insulate. Then do ceiling radiant assembly. Now you have two zone you can control separately.

    Also ceiling radiant back losses are not that high to effectively heat a room above with back losses alone.

  • Cavallo
    Cavallo Member Posts: 22
    edited May 2014

    Thanks, guys! I suspected the issue would be one of control. There's no real *need* for me to keep all the pipes in the 2nd floor floor/1st floor ceiling, other than the idea that it seems to have a certain elegance. There are no walls or ceilings anywhere yet, so I could very well wind up with radiant ceilings on both floors. Or something else entirely. Not sure yet.

    I have to say, though, radiant ceilings sound like an extremely attractive option. I keep trying to figure out what the downside would be to such a system, and I really can't think of any.
  • Gordy
    Gordy Member Posts: 9,546
    Ceiling rad down side

    None I live with them. Floors add elegance in baths and tiled kitchens basements.
  • Rich_49
    Rich_49 Member Posts: 2,766

    that heat rises is the only obstacle to getting people to agree .  Sometimes you must un teach people what their third grade science teacher told them
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    Serving most of New Jersey, Eastern Pa .
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