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Delta FL, radiant electric heat, & self-leveling compound

2467 Views 4 Replies 2 Participants Last post by  jeffro83
just curious if anyone has had a similar situation, or could give some advice.

my scenario:
-100+ yr old house, poured concrete slab, with about 20sq ft of dirt exposed at the highest/uphill side of it...just dug up the area to see what was there, and it appears to be a shallow drain or weeping tile, which eventually is coupled w/ an ABS pipe

-fairly heavily sloped from one end to the other (with little drainage tracks left whenever the basement was poured, all leading to the main floor drain), it's generally uneven in spots, but not EVERYwhere

-planning on having the most uphill side (i know, that sounds terrible) of the basement as a bedroom (the area with dirt at the highest point), which also has the most slope of the basement...over the 13ft or so (from the insulated wall to the closest part of the yellow extension cord in the picture), there's about a 2.5-3" difference in height from the dirt side to where the room will end

-as i don't have much clearance height in this old basement, i'm trying to save as much headroom as possible when filling in this gap


i've got delta FL that i'll be using on top of the slab as a vapor barrier, and i plan to put self-leveling compound on top of that, which i'll be setting a radiant electric heating cable system inside of....obviously if i'm dealing with 3" of slope over 13ft, that's a heck of a lot of SLC. should i just use mix & pour concrete to fill in the dirt part (digging the dirt out to at least the depth of the concrete beside it) and then level, also w/ mix & pour concrete to roughly the 2" height at the lowest part of where the room will end, and then put down the delta FL & SLC over the delta? also, i planned to do the same thing with the bathroom side (the left side of the picture), though the slope is not nearly as bad as the bedroom side.



any thoughts?
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I can't speak to your fill issues but I would say that instead of just using a vapor barrier I would use a vapor barrier/insulator (Like NOFP.COM's "The Barrier") so that you're not trying to keep up with a 55 degree slab. Then do a heat loss calc to figure out how much heat you'll need from the radiant to know which product (for wattage output) and the element spacing to meet it.
I can't speak to your fill issues but I would say that instead of just using a vapor barrier I would use a vapor barrier/insulator (Like NOFP.COM's "The Barrier") so that you're not trying to keep up with a 55 degree slab. Then do a heat loss calc to figure out how much heat you'll need from the radiant to know which product (for wattage output) and the element spacing to meet it.
thanks for the reply! apart from the fact that i special ordered & bought the delta barrier already (and can't return it), i think what i'll end up doing is just using 1/8" cork underlay on top of the delta. because yes, i don't really want to have my slab acting as a perfect (and huge) heat sink. not good.
Whose element are you using? What's the wattage out? Is the radiant your primary heat or secondary?
Whose element are you using? What's the wattage out? Is the radiant your primary heat or secondary?
was going with suntouch warmwire (~12w per ft), as my basement's primary heatsource, i insulated the entire basement perimeter wall a few months ago w/ 2" rigid foam (R10)
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