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Radiant Heating Below Paddle Ball Court

Hi All :

Calling on the radiant experts help! I have a specialized application. I'd like to install a hydronic snow & ice melt system beneath aluminum paddle ball courts. The sport is best enjoyed in the cold. Our design is to close off the area beneath the courts with exterior walls, and spray foam the walls with R30 insulation. The floor we may use bubble wrap as it will be exposed ground. We intend on using ultra fin for this 150'x60' area beneath :

7500' pex tubing
11,200 Fins (5600 pairs)
2800 SN312 Hangers
1- 7 Port Distribution Manifold
1- 6 Port Distribution Manifold

My only concern is not having insulation directly below the ultra fins, but since the entire perimeter beneath the courts will be insulated with R30, the ground will really only be my area of heat loss, otherwise directed above to the terrific court material being aluminum and melting the snow to drip to beneath the deck and drain into the ground via holes in the laid bubble wrap.

I haven't done a heat loss, if anyone is able to tell me if it's even worth it to do, please let me know! Design will be 55 btuh/ft2. I have read snowmelting at 125btuh/ft2. Customer expects no snow to accumulate; perhaps stage 1 radiant stage 2 hydrocoil? I have also read dan hallohan explain not to mix radiant with forced air as it will perform worse together than alone each independently, but this is not high mass radiant, and will be run at 180*F via ultra fins.

I think this will be a superior option to massive rocket heaters blasting 1mm btuh beneath athletes playing spots! Thoughts?



  • JohnNY
    JohnNY Member Posts: 3,226
    Do you have a question?
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Consulting & Troubleshooting
    Heating in NYC or NJ.
  • Zman
    Zman Member Posts: 7,542
    What is the floor thickness and material? Does it have holes?

    What is the output of the ultra fins?

    At 55 btu/ ft you will have some accumulation with anything more than light snow.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Jamie Hall
    Jamie Hall Member Posts: 22,875
    The OP doesn't seem to have a question, but he does say "thoughts?". Well, I have one. The proposed bubblewrap insulation is almost useless. Not quite, but almost. And he's quite right in thinking that insulation will help -- a lot.

    An IR reflective layer is probably a good idea, but it could be simply aluminium foil. That should be over two to four inches of blueboard or similar rigid foam insulation.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Whitefaceadk
    Whitefaceadk Member Posts: 9
    Thanks for the input!!! The customer is expecting no accumulation of snow. My concern with putting foam insulation direct below the suspended radiant fins is for drainage. There is spacing between the aluminum court decking boards, for air to flow. We are going to install some large louvers and fans to move air beneath the space during summer / off winter season as it may become very tight under there with 4" of foam insulation on all the walls. We are going to close up the openings at the base of all the walls. (photos attached).

    I suppose we could put some insulation below however the labor cost will substantially increase. Also, I fear drainage issues, potential mold growth from the web foam. The aluminum ultra fins shouldn't have an issue with the melting snow/rain falling onto it. There will be no use of salt etc either so would expect minimal corrosion.
  • Zman
    Zman Member Posts: 7,542
    How porous is the floor? How many days/hours will it run? Does it run only when it snows or all the time?

    Have you considered insulating the outside walls only and running galvanized/perforated ducts or ductsox under it? You could then install a modulating indirect or direct fire rooftop MAU outside the court and have it push air into the space and out through the cracks on top. The air temp could be controlled by timer, outdoor reset and snow sensor.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Whitefaceadk
    Whitefaceadk Member Posts: 9
    attached copy of the aluminum decking from above. about 1/4"-3/8" between boards

    the existing system is propane kicker rocket heaters. so long as we stick with hydronic, i'm with it. i like the radiant as it will provide even heat distribution. I can provide them with a line item to insulate 2" foam board beneath the ultra fins, which would ensure no snow would accumulate ever. keep small openings on corners for rain/water to run off. they are i beams and so will rest right on the lips of the framing below.

    exploring your tip : if we insulate and seal everything below, and create positive pressure in the space where the hot air can only go up, that sounds terrific - however, even distribution of heat can go up against radiant design?

  • ratio
    ratio Member Posts: 3,600
    I think I'd look into attaching a pipe/tube to the bottom of the planking, which looks an awful lot like a huge heat spreader. Anything mounted more than a few inches underneath will have to deal with 32° water dripping on it while operating, I can't imagine that'll help with the convective output of the fin tube that we need to heat the planking above. You could even spray-foam the bottom of the planks as long as the drainage gap remains unobstructed.
  • Zman
    Zman Member Posts: 7,542
    Yeah, maybe you don't want to force the heat out of the space,the players would love it though :D A forced-air recirc system would keep the heat in.
    If you go the hydronic route,I would suggest sizing the emitters as generously as possible so you can increase water temp or add more boiler if needed.
    In either case, you are in relatively unchartered waters. Keep us posted, this is an interesting one.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Zman
    Zman Member Posts: 7,542
    Is there any way to rivit or screw joist tracks to the bottom of the decking?
    I dream of a system like that every time I sit at an outdoor sporting event.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Whitefaceadk
    Whitefaceadk Member Posts: 9
    It appears this industry is extremely small; I just contacted the manufacturer / installing company of this decking, and got a voicemail that she is on her "honeymoon finally for a week - be back the 18th of october".

    I'm only designing and quoting this job because I think it's pretty cool too - keep you posted!
  • curtm67
    curtm67 Member Posts: 1
    Whitefaceadk, Contact Alan Deal at Performance Engineering Group; 734-266-5300. When I worked there we were working on this exact same type of project. I do not recall if they ended up doing it, and if so how it worked out, but Alan should be able to give you some great insight.
    Erin Holohan Haskell
  • Glenn_16
    Glenn_16 Member Posts: 14
    Scariest thing I ever serviced was under a similar court built over a crawlspace. They heated the court with massive direct fired propane heaters! Talk about no place to run!