Radiant Snowmelt

Earthfire

I still use styrofoam. Dow blueboard not gray , owens corning pink styrofoam and there are a couple of other manufacturers. If it has foil on it I wouldn't use it.

Jim Vey, HVAC Contractor, Bridgeport, CT.

Insulating slab for radiant snowmelt driveway?

I am in the process of reworking my driveway incorporating a radiant snowmelt slab.

My question is: how necessary, if at all, is it to insulate the underside of the slab? Is it an absolute requirement or can I leave it out.

Please call 203-374-8614 if you have any expertise in this area and can offer an opinion. I do not have internet access most of the time. Experienced contractors only please.


Thanks in advance,
Jim Vey, Independent HVAC Contractor

Earthfire

underslab ins.

In snowmelt season the ground in contact with the slab is almost as cold as the air above. Heat goes to cold!!!Heat is dumb that is all it knows,and it is lazy. How do you entice it to go where you want it to work ? You insulate under the slab , and the lazy heat btus will go to the cold surface of the slab because its easier then going thru the insulation. Also don't use polyisocyanate foam board in ground contact. Not rated by manufacturers for such as it absorbes more water then extruded styrofoam like Dow blue board or the owens corning pink stuff. And I would istall a slabsensor well now, even if you don't want to use a sensor at this time run a piece of conduit to it so you can feed the wire thru in the future

rick_4

what type insulation would u use?

hr

insulation choices

watch the weight ratings also on those foam products. If you have any truck traffic the lumber yard foams may not be adequate, some of it is only 15 psi.

Dow has a chart of the US showing areas of high termite activity, another thing to keep in mind with foam. Some building codes prohibit the use of foam in contact with the ground, I've read. Treating the soil with termicides may be acceptable, however it may not last.

Lots of installers going to the roll insulation products. True R values are still questionable. Workability on uneven grade is much better. Not a lot of R value in broken pieces of foamboard!

hot rod

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Michael B

insul-tarp

We sell a product called insul-tarp. R-10 rating, very substantial product, comes in various, easy to use rolls. I like it better then blue board or "reflective" insulation.