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.
Slab edge insulation at garage door.
Push insulation flat against door and feel for retention clips.
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 easiest is a slab supported by good dirt and a new one at that.
Slab insulation is required when.
Or you could double layer your 1 goods.
Slice inch slits through the insulation above the retention clips and attach the front of the retention clips to the back pieces to secure the insulation panels.
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.
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.
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.
You make the assembly out of three pieces a footing a stem wall and the flat plate slab part.
The slab edge system in the link is only r7.
The f factors for slab on grade floors are defined in standard 90 1.
Horizontal insulation placed less than 12 inches below the ground surface or that portion of horizontal insulation extending outward more than 24 inches from the foundation edge should be protected against damage by use of a concrete slab or asphalt paving on the ground surface directly above the insulation or by cementitious board plywood rated for below ground use or other acceptable materials approved by the code official placed below ground directly above the top surface.
In climate zones 4 and 5 the code requires certain slabs below grade slabs that are less than 12 in.
Continuous insulation extends downward from the top of the slab and along the entire perimeter and completely covers the entire area under the slab.