Rigid insulation

[Gatores]

We are going to insulate our shop ceiling with that rigid 2" insulation and the big M sells a regular version and a high density version. The guy working at the store had no clue on what the difference was so looking for insight. It was a 2.50 premium for the high density and wondering if it is better?

Thanks

[Gus]

I could be mistaken, but I believe the high density would be for flooring applications. Insulating for in floor heat, etc.

[CAMAN]

Not quite sure what products you're looking at but if you're looking at the Foamular 150 and 250, then the 150 has a compressive strength of 15psi and the 250 has a compressive strength of 25psi.

For something like a ceiling or wall the 150 will do just fine.

One concern I have though is if this stuff be covered with something? (drywall, paneling, etc.)

I'm not sure of the exact laws on this issue, but if it isn't covered it can make a very dangerous situation. Not only is it flammable, but if it does catch fire the fumes it gives off can knock a guy out before you get a chance to escape. I believe there may even be a code that says you need it covered.

[Tom7227]

Could you put up corrugated metal on the ceiling and solve any fire issues? My brother in law put it on the walls in his shop and it makes it pretty easy to clean. The white stuff reflects the light very well. A couple ceiling fans and he's good to go both summer and winter.