Radiant Barrier Insulation

cdx plywood. You can find some with one side sanded. Be picky, you’ll find it. Stay away from osb and bare board. I would not use Masonite either.

I agree !!! I sheathed the inside of part of my garage with CDX and it worked great. I just painted over it with exterior house paint. Whatever I want to put on the wall, I can put it anywhere I want, for really heavy stuff I just look for the nail heads. and it really stiffens the whole building.