My insulation strategy came from Faroutride
Instruction video
A picture of the interior and insulation of my van van in 3 phrases below:
Step 1: Sound Deadener
Step 2: Thinsulate (see bottom - back)
Installation:
1) Put Rivet in all the holes.
2) Put sound deadening on each big wall spot
3) Apply 3M 90 spray and put Thinsulate on wall and stuff it in every nook and cranny
4) Add Low-E or EZCool to exposed metal.
5) Add Furring Strip
Purchase:
1) Rivet Nut tool - https://tacklifetools.com/products/tacklife-professional-rivet-nut-tool-11-rivet-hhnp2a
2) Stainless steel Rivet size in Promaster to buy::
1/4″ 20
5/16″ 18
#10-24
#10-24 Hexagonal
3) 1 1/4″ stainless steel long bolts to buy:
#10-24,
1/4″-20
5/16″-18
4) Furring Strip
Ceiling: 1 x 3 inch Poplar wood
Sidewalls: 1×2 inch furring strips
Furring strip on front and back a little more tedious - read blog above.
5) Sound Deadening