In climate zones 4 and 5 the code requires certain slabs below grade slabs that are less than 12 in.
Slab edge insulation at garage door.
The f factors for slab on grade floors are defined in standard 90 1.
If the slab has hydronic tubing the minimum r value of this insulation increases to r 15.
You make the assembly out of three pieces a footing a stem wall and the flat plate slab part.
Push insulation flat against door and feel for retention clips.
Even if you find products designed for application against a garage door the constant movement of the garage door will eventually cause them to flake pull apart and fail which means that you re looking at insulating your door again and again.
The easiest is a slab supported by good dirt and a new one at that.
So neither bat insulation or spray foam insulation is going to work well on the garage door.
Then you insulate it under it and on the inside of the perimeter making sure you uncouple the plate from the stem wall at its edge.
2 thick t g xps comes in 2 wide sections by a number of different lengths 8 10 12 and on edge at the door would deliver r10 down to about the same depth as your interior insulation.
The slab edge system in the link is only r7.
This edge thing is a big deal the thermal bridging that occurs if you don t do it costs you more than half the thermal resistance of the whole deal.
Slab insulation is required when.
Or you could double layer your 1 goods.
Below grade to have r 10 vertical insulation at the slab perimeter extending downward from the top of the slab to a depth of at least 2 ft.
Continuous insulation extends downward from the top of the slab and along the entire perimeter and completely covers the entire area under the slab.