building growing rm, off gasing question

I have an insulated attic except the inside wall that backs up against a bathroom. I want to make sure its quiet.I saw some thin reflective insulation at Home depot. thinness is what I like. It should make fan pretty much undetectable. I may put mylar over it. Regardless, would this stuff off gas any thing? It is rated against fire/heat up to 250 degrees but still wondered because I hear some grow tents made in china 'off gas" unwanted stuff. One more thing, I have a plywood floor and I am not sure mylar would hold up with me walking on it. Any suggestions there also. Thank you.