Underslab Insulation At Garage Door Threshold

[CudaA39]

30x50 post frame in PA, 2 10x10 doors. Currently laying down the 2" XPS sheets and realized I'm not entirely sure what to do at the garage door opening regarding the insulation.

Should I just piece the sheets straight across the interior door opening, or should they extend into the approach area under the door as well?

The approach into the doorways will eventually match to a future concrete driveway (same contractor is doing both the garage floor and eventual driveway).

Apologies if this is a stupid question, or covered elsewhere

 

[ConCretin]

My preferred method is to form a thickened slab edge just inside where my overhead doors will land. I then place a sloped apron that extends a couple feet beyond the face of the building starting an inch or so below the first placement. This creates a perfect spot for a thermal break especially with a radiant slab and the lip guarantees I won't get water running back under my door. It's a little more work but well worth it in my opinion.

 

[CudaA39]

Correct, I believe that will be how the approach is laid out for the purposes of the concrete, but I wasn't sure if I should extend the underslab insulation outside of the door or cut it right where the door touches down.

There is roughly 12" of concrete that will extend from the door to the exterior front wall outside due to the width of the wall. Wasn't sure if it was worth trying to insulate this section or if it would lose an issue since that is so heavily trafficked

 

[ConCretin]

The only benefit to extending the rigid out under the apron would be frost protection. If you get frost and don't want it to lift the apron, insulate under it and beyond a distance equal to your frost depth.

 

[yeldogt]

Some people like a flush drive into the garage ..... I like the garage floor to be about an 1 1/2 higher so there is a water and dirt block from the apron. I typically place the garage slab just inside the door -- this way the insulated door comes down on the apron protecting the edge of the heated slab. i just use a typical tar-strip at that spot. If the driveway is all concrete the slope starts there so the apron and drive match ...... if blacktop it's not as noticeable and I just do a normal slope on the apron. I normally make the apron a little larger (wider) with black top.

there is no perfect solution at that spot

 

[billconner]

I'm with willysfan on insulation extent, especially extending it to frost protect slab. I would like a sawcut inline with exterior of building if you are in a freezing climate.

I saw a nifty tip in FHB long ago. The set a 1" galvanized pipe just inside overhead door so floor is level with top of pipe and slab door lands on is 1/2 to 3/4" lower. Nice durable transition. Have seen that done with galvanized angle also but suspect the pipe is more readily available.