Shaun Eli wrote:
I have a basement wall that's a few inches from my water heater and
also quite near my furnace. I want to insulate that wall and I can't
do it from the other side.

There isn't room to put studs and fiberglass insulation and then cover
it with wallboard. And I don't think it's a good idea to use
polystyrene insulation because it's pretty flammable.

Is there any other type of insulation with a high R value (because
there's only a couple of inches of room) that isn't extremely
flammable that I could put into that space?


Asbestos.