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Concrete slab

347
347 Member Posts: 135
Hello All,
I'm bidding a radiant job for a kitchen, bath and office remodel.
Were going with two zones, one will be on a existing concrete slab and the second to be be on a concrete slab with part of it (45%) over an existing crawl space with wood floor.
I'm thinking of using fast track by Uponor over the slab and install the tubing in the fast track. I think that should be good for a thermal break on the slab (and over the wood floor to keep it uniformed) to keep the heat where it belongs .
Just wondering what you do in s situation like this. The heat loss has not been done yet.
Thanks for you help.

Comments

  • Ironman
    Ironman Member Posts: 7,062
    Beware of relying completely on radiant in kitchens and baths: anything that's covered by cabinets, fixtures or appliances will be a dead zone that doesn't give off heat.

    Also: be careful about zoning up a low mass boiler; that's a recipe for short cycling.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • 347
    347 Member Posts: 135
    Thanks Bob, I know about cabinets and appliances with the radiant floor heat. I still need to do a heat loss and I also told the homeowner that she may need secondary heating in both of those rooms. My question was about the type of material (polystyrene?) that should be used under the mud and on top of the existing slab to stop the heat from going down instead of upward.
  • hot_rod
    hot_rod Member Posts: 18,189
    The more insulation the better to keep the heat from traveling down. it seem to always come down to head room, cost, and complexity of adding r-value over concrete slabs.

    You might need a couple different SWT for the slab and a dry system? the load and design will indicate that along with any additional heat input.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Ironman
    Ironman Member Posts: 7,062
    Green board (polystyrene) or a radiant mat that the tubing velcros onto like Rehau has.

    As hot rod said, get as much as they'll allow.

    Another option which only requires less than an inch is Raupanel. It can output 30 btus per sq. ft., but it's not cheap.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • 347
    347 Member Posts: 135
    Height might be an issue because the contractor installed the doors and refuses to raise them. They want me to install on the concrete but I told I would not do it and guarantee performance.

    Bob, I'll look into those panels, thanks again.