one small detail could make big results

Simply Rad

Just yesterday I was at a job and noticed the snow was melted where there is no snowmelt.  I swear the owner thinks its part of the snowmelt system, but it is not. 

The detail is the garage door area.  The slab is heated and there is no insulation to stop the thermal migration out to the abyss(the drive way).  The exact detail is where the heated slab stops and where the drive starts.  I think its a good idea to allow the slab to have some heat, to prevent the garage doors from freezing to the slab.  But I would like to stop it there.  Even with the concrete expansion joint heat migrates to the concrete drive way.  I do not know of any product out there, but I have thought long and hard about it.



Jeffrey

NRT_Rob

our shop builder

uses a pressure treated edge break. it's not insulation, but it's wood instead of concrete so it is a basic thermal break at least.



I haven't seen many better details, unfortunately.

Lance

Migration of heat

You got it right. No insulation barrier to slow heat transfer.

Heat energy always seeks to migrate from a high state to a lower state.  Insulation can slow the transfer but not stop it. All will continue until equlibrium occurs.

To create the effect of a wall to slow this heat transfer a trench or slot can be cut in the concrete and an insulation slab of foam or a thermal resistance material be placed in this area. This will achieve savings and the desired results. And if it is cold enough the snow will remain. There will always be a temp difference but not as great.

This is why we install thermal edge insulation with radiant floor. And since insulation is very dependent on thickness to get a good R rating you may need more than 1". An air gap of even a 1/4" in the slab will at least stop the slab conductivity. My first choice would be cut the slab. Caulk just the surface and see how it goes. It must remain water free or it will not work. Good luck.

In the future, snow melt near the edge does not need a lot of heat, perhaps the temp could be lowered. It will still do the job but lessen the waste. You only need maybe 33F after figuring for design loop loss?

In building wall construction wood is not condsidered a thermal break, the air space is. Wood has poor resistance to heat transfer and may not be enough.