> but because Starlite is so lightweight - 1 mm thick Just what about a substance determines how thick it is? How thick is concrete, then? Glass? Is there a r

> but because Starlite is so lightweight - 1 mm thick Just what about a substance determines how thick it is? How thick is concrete, then? Glass? Is there a reason Starlite can't be manufactured 75 mm thick, and would it then not be even more amazingly effective? Or alternatively, what's the thickness value for concrete? Glass? What's the Q-value of 75mm of paper tissue?