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In-slab floor radiant heat — Garage door thermal break

Hondaracer2oo4 | Posted in Green Building Techniques on

I am having the floor pour at the end of this week. Insulation is down on the floor with a bevel at the top, thermal break, at the exterior frost walls.

My question is about the thermal break across the garage bay doors. I had heard of people running the thermal break straight across to keep from bleeding heat right outside to the exposed section of concrete outside the garage doors. My question is how best to accomplish this.

I think I plan on using a piece of L channel steel that is 2″x something to cover the top of the foam and run the concrete slab and small apron area that will be outside the the garage door even with the top of this piece of steel. The question is how to secure the piece of insulation/L channel steel in place. I was concerned when they pour that this insulation and steel will just want to float around or float up. Also should I somehow try to tie together with rebar or mesh the “outside the garage door(just the area between where the door comes down and the exterior edge of the frost wall)” to the garage floor slab itself? I would think that if I didn’t tie the two together somehow than the exterior piece would just want to fall off since it is just a small 8 inch x 9.5 foot section of concrete sitting on top of the frost wall.

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  1. GBA Editor
    Martin Holladay | | #1

    Briefly, there is no good detail for this problem.

    A GBA reader named John Klingel spent a lot of time thinking about insulation details at his garage door threshold. You might want to read two Q&A threads that he started:

    Slab at garage door. How to insulate?

    Retaining heat at a garage door; part 2

    You might also want to read this thread, in which a GBA reader (Brad VanVickle) praised the Energy Edge Slab Insulation system:
    Insulated Slab - Entrance and Edge Details.

    Finally, here's a link to another GBA thread on this issue:
    Slab — thermal break at vehicle roll gate.

  2. tdbaugha | | #2

    Anyone solve this problem with some of the new products on the market these days?

    Partel "Alma Vert":

    Their website lists an even higher density board, 350 kg/m2 which should have a compressive strength of like ~800psi


    This is much lower R value but SUPER strong.

    Here's another one that's similar:

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