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Radiant heat over concrete Slab on grade

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I am looking my best option. I live in Buffalo, Ny. I am converting a 1800 sq ft garage with apartment over it into a single family home. The apartment is additionally 1000 sq ft. Currently heated with baseboard heat, a boiler. We want to do radiant heat on the ground level grade on slab and have a valve zone to also include the baseboard heat for the upstairs. We don't want a pour over gyptcreed type installation. We want something that will softer on the legs and feet. Something that we can apply our luxury vinyl flooring over the top with either luan, or directly over. We have gotten many quotes, all with different applications. But we are not sold on any as of yet. We will be using 3" closed cell spray foam in the walls. We have had heat loss analysis done, it was 27%. One quote was Uponor product with pore over. One was with Comfort Pro AquaHeat ProPanel. We don't want to loose ceiling height.
This is obviously a retrofit, I just don't want to make a costly mistake. I don't have room for ductwork. I do not like heat pumps with units hung on the walls. Plus it won't cure the fact there is baseboard heat upstairs. I am open for ideas. It seems we are on the cusp of new technology, but it hasn't been honed yet to be the perfect solution.

Comments

  • nate379
    nate379 Member Posts: 37
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    Could put Baseboard radiators downstairs as well.

    How low is the used to be a garage ceilingthat loosing 2-3" is an issue

  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,245
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    Is 2-3" s really going to bother you? Unless you have an abnormally low ceiling height now, you'll never notice it. Your insulated heating source is way more important than a very minor aesthetician. If you get past that, you have a myriad of choices with radiant. And different scenarios and materials.My two cents. Mad Dog

  • Connieweil
    Connieweil Member Posts: 8
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    It's the step up that also comes into play, 2-3 " is fine it's when you put sleepers 2" foam boards, subfloor, radiant heat, then flooring…your at 5-6"

  • dko
    dko Member Posts: 644
    edited March 2023
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    edit: Didn't see previous post

  • Connieweil
    Connieweil Member Posts: 8
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    My concerns are there is very little R value in those products, so would I have a much higher heat load.

  • dko
    dko Member Posts: 644
    edited March 2023
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    Roth panels provide a great panel system that offers 6" OC

    https://www.roth-america.com/product/radiant/radiant-panel-installation-systems/

  • Connieweil
    Connieweil Member Posts: 8
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    Yes actually I contacted the eastern representative for Roth, waiting to hear back.

  • psb75
    psb75 Member Posts: 863
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    There is also the option of radiant ceiling. Though this then depends on original construction details and your willingness to "build down." It needs insulation above it.

  • Connieweil
    Connieweil Member Posts: 8
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    My end goal is to not have cold concrete floors. I am sure code will require some insulation of some type.

  • psb75
    psb75 Member Posts: 863
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    If you are doing ANY heat on an existing slab you MUST have a thermal break (insulation) between the heat and the unheated slab. There is "code" and then… there are the LAWS of thermodynamics. Follow the "law" and you won't have cold concrete floors.

  • Connieweil
    Connieweil Member Posts: 8
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    I asked that when the contractor showed me the product, there was only a foil backed piece. I keep questioning that same thought. But 3 contractors are not addressing that point.

  • Connieweil
    Connieweil Member Posts: 8
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    Thermal break: what would be the best application, besides 2 inch ridged foam. I just can't see the Aqua board or the Uponor product having any R value. But they are insisting it will work!

  • psb75
    psb75 Member Posts: 863
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    What about this product: Warmboard? They have excellent client/contractor tech support. It is a premium product.

    WARMBOARD-R

    Designed specifically for remodels, this full-faced overlay panel typically installs over concrete or existing subfloor. Panels are 2’x4’, 13/16” thick and made from high quality OSB. While we design the panel layouts for you, field modifications can be made easily to accommodate any needs.

    Allislandradiant
  • hot_rod
    hot_rod Member Posts: 22,476
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    1 or 1-1/2" foam is an option also. You need to balance how much thermal break you consider adequate, and the height penalty. r-5 per inch of extruded foam.

    I like the Roth panels, aluminum layer 6" spacing. There is very little foam under the tube however, so R value is questionable across the panel. The tube being the hottest point will transfer energy to the cold slab.

    You have multiple trade off to consider.

    Plenty of slab homes out there with pad and carpet, no radiant. Radiant ceilings or walls will keep the space warm.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Connieweil
    Connieweil Member Posts: 8
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    Can I add a layer of 1 in foam down and then place the Roth panels down on top of the foam, or would I need sleepers and subfloor?

  • hot_rod
    hot_rod Member Posts: 22,476
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    If you use foam rated adhesive to keep it all put. I use a notched trowel to glue down the Roth to concrete, adhesive in 5 gallon buckets, rated for foam use. You can find 1-1/2" foam sheets that have a tounge and groove edge, they connect and lay flat, better.

    Then you could use any of the floating hardwood or laminates right over the Roth.

    If you wanted a glue down flooring like cork tiles, etc, you would need a layer of Luan underlayment, also glued down.

    If the floor is very uneven you may need some concrete anchor shots through the entire assembly.

    In my camper build I used RevolutionPly, a .197 thickness water resistent underlayment. Lowes sells it. Seems a bit more engineered than standard luan. It doesn't turn into a potato chip shape like thin luan :)

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream