Metal workshop soundproofing
I have a corrugated metal sheet building I would like to use as a hobby woodworking workshop. I read a bunch about how to soundproof, but I'd like to validate my plans by others who have more knowledge about soundproofing.
I want to dampen the noises of the machines I will use so that I bother the neighbors a bit less.
My plan is to build a second wall with a timber frame and drywall with a bit of an offset from the existing metal sheet wall and use mineral wool (rockwool) for noise dampening + thermal insulation.
Should I attach the rockwool to the metal sheet, to the second timber framed drywall or stuff it between them without leaving an airgap?
I read somewhere that you need a moisture barrier if you insulate metal buildings, but I am a bit confused. Where would the moisture barrier go? Directly on the sheet metal, or after the rockwool?
I am in the EU so certain brands may be not available in my country (most reddit posts talk about US products), but I think we should have similar materials.