Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

how to isolate garage slab from apron

Ericjeeper Member Posts: 179
I am building a new home on a slab with radiant pex in the slab. Yes I have done a heat loss on it.. But my question is .. How do I interupt the slab at the garage door.. In other words how do I make a good thermal break.. I had thought maybe use some sort of continuous trench drain sitting on 2 inches of styrofoam?Or would just putting in a piece of treated two by.. with styrofoam cut at an angle so I would not end up with a full two inch of styofoam soft spot?.. Am I confusing you?Sorry..


  • thermal break

    I wouldn't worry about it. Any heat that escapes will keep the snow and ice from accumulating around the bottom of the door. My shop has a north facing door, here in southern Iowa. Lots of days around 0 degrees, and it is not a problem, but a benefit.
  • Mike Kraft_2
    Mike Kraft_2 Member Posts: 398
    plagerized directly from Siggy

    Secondly, don’t insulate the edge of the garage slab at the overhead doors. This allows the snow and ice to melt a few inches out from the door. It also prevents the door’s bottom gasket from freezing to the slab. Your garage door opener will appreciate this detail when it’s time to lift the gasket off the floor. All other edges of the slab as well as its underside should be insulated. We used 1 1/2-inch thick/25 psi-rated extruded polystyrene, which has plenty of bearing strength for cars and pickups.

    This is from February P&M article.Here's the link.


    This said I agree with Mikes previous post:)

  • Boilerpro_3
    Boilerpro_3 Member Posts: 1,231
    Use an expansion joint

    just outside the door. It provides a thermal break and allow the concrete to settle neatly.

  • jw
    jw Member Posts: 62

    2" high density foam. Cut back at a 45 or steeper angle and score foam 1/2" down. After you pour concrete, peel out the 1/2" piece on the top (which is why you score it) and fill the resultant 1/2 by 1/2 void with a pourable high quality sealant made for expansion joints. If this is right under the door seal, it will not freeze and will also keep your heat where it belongs. Should be able to handle a fair bit of traffic, altho I would not use it for tracked equipment.
This discussion has been closed.