I have a duplex built in the 1950s. I would like to fix an acoustic issue where impact and airborne noise travels easily from the upper unit to the lower unit (units are separately rented). Noise from poor acoustics has caused problems mostly for the lower unit tenants (from impact noise such as from tenant upstairs walking and airborne noise such as talking (yelling sometimes), music, tv, etc) and has caused tenants to want to move out due to the noise issue.
I looked online for construction techniques to substantially reduce noise and would like to get your input if you addressed acoustics issues with your rental property or if you have expertise in how to address this issue.
I am considering removing the existing ceiling drywall in the lower unit to expose the wood studs. Any holes, gaps, or other openings would be filled in with acoustical glue (such as Green Glue) or acoustical putty. Next, fill all the spaces between the wood studs with soundproof insulation such as Roxul Safe & Sound. Next, add resilient channels and then attach drywall to the resilient channels.
In regard to adding drywall, I will have to consider using perhaps soundproof drywall (such as Quiet Rock) or adding two layers with drywall (maybe even add a layer of Green Glue between the drywall). Also, for good measure, I want to consider whether or not to add a layer of Mass Loaded Vynil (2 lb) after installing Safe&Sound insulation but before adding the resilient channels and drywall.
Further, should I soundproof the exterior walls in addition to the ceiling.
Your input and feedback would be greatly appreciated
It's an expensive under-taking. I have an apartment complex that is very problematic. If it's really quiet downstairs, you can literally hear a regular conversation upstairs. Walking sounds like someone stomping. Closing a kitchen cabinet sounds like someone is slamming it. Very frustrating.
Rather than tear the place down to the studs and spend tens of thousands trying to reduce noise, we simply warn everyone HEAVILY before they rent. They still express frustration, but they accept it because they've been warned. I haven't had anyone try to terminate a lease specifically because of noise.
I own two over-under duplexes. I live in the bottom floor of one of them.
1. Rugs and/or carpeting upstairs help the problem.
2. No small children upstairs help the problem.
3. Ask the people upstairs to take off their shoes.
4. The level of noise fix you are proposing is basically equivalent to building a soundproof musical studio. If you're willing to go to that expense or effort, more power to you! If not, here are three easier fixes you can try.
a. Acoustic glue-up panels
b. Dropped ceiling with acousic panels.
c. Second layer of finished drywall ceiling held in place with 2-inch screws.
5. If you lower the rent for the people downstairs, every time they hear noise upstairs it will remind them why they are paying less. In my case, I live downstairs in one of these duplexes. Every time the people upstairs make some noise, I actually feel like it's my money singing to me, telling me why I live free. I am not saying this is particularly normal, but, well, over the years I have developed an extraordinary loathing for paying mortgages, rents, HOA fees, utilities, building insurance premiums, and of course property taxes.
As free as the wind blows
As free as the grass grows
Born free to follow your heart...
And beauty surrounds you
The world still astounds you
Each time you look at a star...
Where no walls divide you
You're free as a roaring tide so there's no need to hide...
And life is worth living
But only worth living
'Cause you're born free...
If you are going to start ripping things apart, maybe look at the spray-in closed cell insulation as an option. It is dense and seals in the nooks and crannies quite well.
I agree with @Jim K. . Rugs and carpets would likely muffle the noise issue, but may not deal with it completely.
Thank you for your input, I appreciate it. I will have to weigh all the options. It makes sense not to overspend when there are less expensive alternatives including warning tenants in advance and having them agree to be considerate in regard to noise levels.
We had a similar issue as had hardwood floors. Not sure what you have in the upstairs unit but we carpeted the upstairs & it made a huge difference.