Soundproof Insulation - expensive?

[Diane G.]

Has anyone done soundproof insulation in the ceiling?  Is that effective in terms of cutting down noise level?  How expensive is it?  Thank you in advance

[Roy N.]

@Diane G.

When you say "soundproof" are you simply trying to reduce noise between units or are you looking for recording studio quiet?

If you are looking to deaden sound between units, you can use a dense mineral wool such as Roxul Safe-n-Sound in the joist cavities and then use resilient channel to hang the 5/8 (fire code) drywall on the ceiling - perhaps with shims.

Since you need to provide adequate fire separation between units, you can address both matters at once.  Where we operate that means using a non combustable barrier (such as dense mineral wool) in the floor cavities with 1 (or 2) layers of 5/8 fire rated (Fire-X) drywall on the underside ceiling.