I live in a 1-story condominium. The unit above my bedroom makes 3 types of noise that bothers me: 1. General walking noises 2. There is a toilet/shower above me. 3. There is a washing machine above me. I already tore down my bedroom ceiling once before and had someone insulate it. At the time I really didn't know much about insulation. I kept telling the guy that I needed to soundproof it as much as possible, and that the only reason I was having this done was for sound purposes. He kept saying that this would work out great. He put some Kraft-faced R19 insulation between the ceiling and the floor joists. The ceiling drywall that was selected was 5/8" thick, and was called Firerock, which was supposed to be thicker and more dense than regular drywall. I was very dissappointed to find that this helped a little bit, but not as much as I expected. I am planning to tear it down and re-insulate it again, because nothing is more annoying than to be woken up by noise. My question is the following: 1. Is there a problem with having too much insulation? Do you need to have air ventilation? The R19 insulation only filled about half the depth of the space between the floor and ceiling. I was thinking about putting in two layers of Owens Corning QuiteZone Acoustic Batts [3 1/2" thick each] and also put in a layer of standard R30 [9"(?)]insulation. This means that there would be no air flow at all. I'm not sure if that would cause moisture to build up and lead to mold problems, or cause the wood to detiorate over time. As far as I know there wouldn't be any heat related problems with the insulation because the only pipes that would touch the insulation would be water drainage pipes from the shower/toilet and washing machine. I know that the special Owens Corning QuiteZone Acoustic Batts are fiberglass, and do not absore moisture. I realize that this will not fully solve the walking around problems as they go through the wood, but it should help out with the other two.