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Snowmelt under asphalt

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Solid_Fuel_Man
Solid_Fuel_Man Member Posts: 2,646
Is it possible? Has anyone done it?

I was wondering if one could lay some XPS and staple pex to it, cover with sand maybe? then top with 2" of asphalt?

Wondering if all snowmelt systems were concrete. I would assume that while placing the 300 degree asphalt, water could be run through the PEX to keep it cool. Just open from a cold water source and dumped on the ground during the driveway placement.

Total dream while its snowing...

I am having my driveway paved this summer, wondering if there was any possibility of connecting some heat to it.
Serving Northern Maine HVAC & Controls. I burn wood, it smells good!

Comments

  • Gordy
    Gordy Member Posts: 9,546
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    @Mad Dog_2 did one with I believe concrete then an asphalt overlay with pex.
    kcoppSolid_Fuel_Man
  • Zman
    Zman Member Posts: 7,573
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    I have seen a few systems from the 1990s with pex in sand with no insulation and an asphalt overlay. The tubing get pretty banged up by the asphalt machines, a couple had leaks. The performance is marginal.
    Concrete is king for radiant.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Solid_Fuel_Man
  • EzzyT
    EzzyT Member Posts: 1,296
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    I have done a few snow melt project with asphalt and am currently doing one.
    This current project is about 4500 square feet of asphalt and about 500 square feet of concrete and pavers.
    This project we used Crete-Heat insulation panels with 3/4” tubing 9” spread.
    Tubing needs to be covered in 2”-4” inches in sand or concrete dust before the asphalt is done.
    E-Travis Mechanical LLC
    Etravismechanical@gmail.com
    201-887-8856
    CanuckerLe JohnSolid_Fuel_Man
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    @EzzyT is that black covering sand? This is similar to what I was thinking. Currently I have compacted crusher dust as the base for the asphalt. Its basically 3/8" minus crushed ledge. Crete-Heat over a near perfect base and compacted sand over that, topped with 2" state-mix asphalt.

    I would assume that as long as there is adaquite insulation below any system would perform ok.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • EzzyT
    EzzyT Member Posts: 1,296
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    @Solid_Fuel_Man No it’s concrete dust, it’s just wet and from the distance that picture was taken it looks like black sand.
    I would confirm with the asphalt company that the 2” state-mix can handle the psi load that will be on top off it and expansion and contraction so it won’t crack and fall apart.
    E-Travis Mechanical LLC
    Etravismechanical@gmail.com
    201-887-8856
  • Zman
    Zman Member Posts: 7,573
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    That looks like a pretty slick way to do asphalt snowmelt. I think that is how I would do it (assuming the customer can't be talked into concrete :D )

    Upside:
    Efficient installation
    Tubes are pretty well protected from the asphalt process
    Asphalt patches easily when damaged

    Downside:
    Tubing is at bottom of assembly
    Tubes do not get full contact with sand
    Wet sand transfers heat 5x as well as dry, hopefully it stays wet down there.

    For the most part, this assembly is similar to pavers. Pavers do allow water to pass through which has advantages.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
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    Up here asphalt is considered superior in driveway applications due to its flexibility and that salt won't deteriorate it.

    My driveway is very steep and the whole point of paving it is so I can scrape it bare with my tractor. Salt would come off the cars parked on the driveway. I'd actually consider concrete as I could do that myself and not have a paving crew. I may figure out how much Crete I'd need. I'd assume 4" thick to be minimum.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Zman
    Zman Member Posts: 7,573
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    4" with rebar on chairs rather than weld wire would be my preference.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Solid_Fuel_Man
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    edited January 2019
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    Yeah, the only reason for wire mesh would be to span the rebar so I'd have something to tie the tube to. Not a fan of mesh only slabs, anywhere. I also get fiber in all the concrete I've done. Bar and fiber seem like really cheap insurance.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
    Zman