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staple up radiant with carpeting????????

Brainstorming how to reduce noise between two floors of split-level duplex, both floors with radiant. Upstairs has radiant staple-up to hardwood floors and footsteps propagate a lot to downstairs. Have already done insulation btwn bays and sound-proofed ceiling assembly. Considering doing wall to wall carpet over hardwood with carpet padding to reduce noise. Kind of assuming that this would render the radiant ineffective, but i'm wondering if anyone on here has seen it done successfully? Is there a such thing as a carpet pad with good sound reduction but but low R-value?


  • hot_rod
    hot_rod Member Posts: 21,878
    What supply temperature are you running now. Does the floor heat the space adequately on the coldest days?

    Here is what carpet and pad will do to the output. So the question becomes ho much hotter will the supply need to be and is that acceptable? 140F is about as hot as you want to run staple up against wood.

    So you would want to know the heat load of the room, then crunch the numbers to see it it can work out, safely and comfortably.

    There are some radiant specific pad, but probably not much sound barrier.

    Buy the tenants thick soled slippers :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • My outdoor heating curve max's. out at 130° water temperature and when I've hit that in the past, my hardwood has split in places. Try to stay below 120°.

    However, the max. water temperature can depend on the plates used. Loose fitting plates can run hotter.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • EternalNoob
    EternalNoob Member Posts: 42
    Thanks guys. Mostly i just wanted to know if this was a ridiculous idea or not. I have been running 110F and the ability to heat the space on the coldest days has been plentifully sufficient here in Northern California. If I'm abandoning the hardwood then i suppose the wood splitting from higher temperature fluctuations will not be a concern, so running 120 makes sense if i need to.
  • hot_rod
    hot_rod Member Posts: 21,878
    So 3/4 sub floor and 3/4 hardwood now? = R 1.8
    1/2 bonded foam pad is R 2.0. 1/2" rubber is .6.
    Carpet can run 1-2 R

    No doubt the thicker pad would offer more sound deadening. That rubber "radiant" pad is fairly hard.

    You carpet pad temperature rating may limit how hot you can run the floor, and thus the BTU you could expect.
    Hopefully it is a low load area :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream