[chrismorse]

Hi Steve,
Is this DIY?
Are any walls/ceiling open, that is, uninsulated, open framing? How much noise reduction are you after?

As mentioned, gaps and holes can let a lot of hot/cold air & noise through.

Building material density, layering and physical separation, all impact noise transmission, so, if your walls are insulated with fiberglass/foam or blown in cellulose, It might be cost prohibitive to go back to the framing to improve the noise reduction with HD rock wool, sound board and high density drywall.

I have removed interior trim/finish, screwed sound board and an additional layer of drywall to an existing wall between apartments.

A more effective & costly approach is to build another framed wall, not connected to an adjacent wall, insulating the gap and applying another layer of drywall. This physical seperation of one wall from another is the most effective way to prevent sound from transmitting vibration from one room to another, or from outside to the inside.

I did a major remodel, changing a downstairs basement to a seperate unit for a newly wed son and daughter in law. We removed the basement ceiling and insulation, (previously inhabited with rats), did the necessayr plumbing and wiring changes, then installed R-30 fiberglass in the ceiling joists, placed strips of 1/4 neoprene on the bottom of the joists and strapped, (crosswise) with 1x6 boards. We then installed 1/2 sound board, then 5/8 drywall.

This did a good job muffling the pitter pat of 5 year old feet on the hardwood floor above in the kitchen. The strapping supported the drywall and minimized the transmission of sound. The rubber isolation also helped.

So, how "open" are the walls, What is in there??

chris