I'm in the planning phase of my basement finishing project and my question concerns where to put the vapor barriers on sound proofed walls. I live in an end unit townhome and I've read everything I can possibly read on sound proofing. I've decided to construct walls with a staggard stud configuration, 5/8" drywall on BOTH sides and insulation weaved in between the studs. I will be building three walls of this type of construction in an alcove portion of the basement, with only one of the walls being shared by my neighbor (so I don't think I'll have any moisture problems from the shared foundation wall.)

That being said, where do I put the vapor barriers if both sides of my walls will be drywalled? The outer layer of drywall is more for vibration dampening purposes than anything else, but I wouldn't want moisture to build up there either. Would greenboard be of good use for the outer portion of this type of sound proofed wall?

thanks in advance.

 

You don't need any vapor barrier on a wall or ceiling that is insulated only for sound. The only time you want a vapor barrier is when there is a significant temperature difference from one side of the wall to the other. And in these cases, you only want one vapor barrier -- on the warmer side.