Author Topic: Duplex: Soundproofing between floors, next steps?  (Read 3953 times)


  • *
  • Posts: 3
Duplex: Soundproofing between floors, next steps?
« on: April 15, 2018, 12:21:30 PM »
Hello -

This community is awesome. I have read numerous stories and learned a lot, my only regret is not finding this website sooner :-o

My story/request:

I have a duplex, which is split level and is of brick construction (exterior walls) and solid wooden joists. I live in the bottom portion and rent out the top. The entire upstairs is carpeted/padded except for the kitchen. The kitchen happens to be above my bedroom. In the past this was not a problem, but my new tenants work late (dont come home til 10-11) and then they are stomping around in the kitchen. I have talked to them about being quite and honestly I am not even sure if its them at this point or just the poor construction. Once I realized this problem I scrambled to fix it in several attempts.

Attempt 1: I cut holes at every joist and blew in insulation. This worked good for the airbone noises. I could not really hear anyone talking or any noise like that. However, I could still hear them walking around and dropping things.

Attempt 2: I found out about Green Glue and read that adding mass to the ceiling would lessen the vibrations. So, I added two layers of 5/8 drywall to the ceiling with green glue sandwiched in between. This helped a bit, but not a dramatic improvement. Airborne noises are virtually non existent, but the impact noises were still easily heard.

Attempt 3: I asked the tenants to let me know when they were going on vacation and I would do some improvements upstairs. The kitchen floor was porceline tile, which was on cement board that was screwed directly to the wooden subfloor - no underlayment. So what I did while there were gone was I installed a floating lament floor on top of the tile floor. I used a premium wool underlayment underneath the floating floor, which claimed high IIC numbers. This seemed to work well. It definitely dampened the impact noise but I can still hear it. Its not terrible, but I have become fixated on figure this out once and for all.

So that takes me to today. I am not sure where I should attack this problem from now. Should I installed a vinyl floor on top of the floating with a better underlayment? Should I throw in the towel on my bedroom ceiling and do a decoupled ceiling? Any suggestions on what would be the best approach?

Thanks for listening!



  • *
  • Posts: 3
Re: Duplex: Soundproofing between floors, next steps?
« Reply #1 on: April 06, 2019, 09:37:07 PM »
Soundproofing between floor in existing construction to reduce impact (footstep) noise is the most common soundproofing request.

You need to decouple the floor. That is done with RC channel. But you can't just add RC channel to an exiting ceiling or you end up with the triple leaf effect - which can magnify the sound. In,4317.0.html I post my recommendation. I'm waiting to hear from Randy S to see if that's a (pun intended) sound approach.

Randy S

  • Guest
Re: Duplex: Soundproofing between floors, next steps?
« Reply #2 on: April 08, 2019, 05:57:40 PM »
to decouple or roll the dice on durometer????

the question of the century...

depending on where you have the room to do one of these applications it would entail losing another 1 1/2" for best reduction or 1/2" for better reduction then you have.

Rick is correct on the channel statement for decoupling but you have applied "MASS LAW" successfully and you would have to decouple then put it back... :(
 in order to reload that amount of mass you would need clip and channel not RC channel as it is not recommended for more then 2 layers of drywall.

as for you attempt upstairs you can pull it all back up except for the cement board layer and tile and install a decoupled floating sublfoor on top ( 2" lift) and this would also prevent flanking impact around a decoupled ceiling below.
I like decoupling over durometer as you have broken the amount of pathways to the original subfloor and used a puck system with a 50-60 durometer apposed to covering the entire floor again only relying on durometer.

Space becomes my only battle on the flooring systems.

Feel free to reach out and call me direct.

Randy S.