noise from stairs

[badman70]

Hi,

I moved in to new construction 3 level townhouse end unit.  The party wall is double studded wall with 3" air gap and insulation on 1 side.  I used acoustical caulking in all rooms before the trim was put up.  I don't have any problem with airborne noise but impact noise.

Both my neighbors stairwells are attached to the other side of the party wall.  The stairs were built with carpet and i doubt they removed it.  And with 4 guys in their 20's living next door they run up and down all day and night. 

Is their anything I can do thats economical?

Dave

[Randy S]

Dave,
When it comes to impact noise the main rule of thumb is to "decouple from the structure". The only way to get a valuable reduction based on cost would be to seperate the stairs from the adjoining wall and soundproof the wall. Any other approach would come with questionable results.

[badman70]

I obviously can’t do anything about moving the neighbor’s stairs and I have not seen walls that are more soundproof than the double wall with 2- 5/8” of drywall on each side and insulation in-between. 

The neighbor’s stairs are carpeted and despite the good wall construction I can still hear them when they run down the stairs because the energy is transmitted directly into the wall.

What about adding a third layer of drywall with green glue in-between?  Their web sight claims to dramatically reduce impact noise.  Would you say their claims are false?

If I did that, flanking noise should now dominate and since there is no floor or ceiling directly above or below my neighbors stairs (2 flights of stairs down and up) the noise could only be transmitted by the landings of the stairs.  At this point I believe most of the energy is being transmitted through the wall.  Once the energy has made it way to my side of the wall, I’m sure it is radiating through my floor and ceiling, but it definitely sounds like it only coming from the wall. 

I hope this should make the impact noise more tolerable, I realize I won’t eliminate it completely.

What is your opinion please?

[Randy S]

Green Glue is a great product, we use it in all of our professional systems. Becuase you can not decouple from the structure, we would view this as a band-aid solution and would deliver some reduction. To maximize your reduction due to impact I would recommend doing a more aggresive "Band-aid".
Two layers of 1/2" drywall and two layers (2 tubes per 4'x8' sheet) of green glue. You can do this 1 layer at a time and review results just keep in mind green glue will take 30 days cure time before you see optimal results.

[badman70]

Thanks for the reply,

It sound like there is some hope for me.  Only 1 other thing i am concerned about.  The wall in question has a couple of outlets.  I guess i will have to get extentions for them, but I know they will degrade performance.  I'm just hoping the project will still be worth it.  What do you think?

Dave

[Randy S]

Yes you will need extentions for the outlets, when you pull the outlet from the box to add the extention use some acoustical caulk and seal the holes in the back of the box (airtight) then get outlet insulators.
Here is a link to show you-- http://www.usahardware.com/inet/shop/item/41360/icn/20-516237/wj_dennis_co/1062.htm
This will help prevent the boxes from being speaker in the wall.

One more thing- If you want to take that "Band-aid" solution up a notch add a layer of MLV w/psa sound barrier in the sandwich and this will help alot.

http://www.soundproofing.org/infopages/flooring.htm

[confuzed]

I have the exact problem - we moved to a newly constructed house and a few mths later our neighbors sold their house, and now our neighbors are a family with 3 young boys who run up and down the hardwood stairs all the time and we can hear and feel the noise and its becoming extremely annoying to me - from going from nice and quiet to loud thumping noises.  We only hear the noise when they go up and down the stairs so i am assuming it is the impact of them ruining that is coming into our house.  Would the recommendation below also help with my problem? the wall where the stairs are, are 2 stories high, would i have install drywall all the way up to the top? Any help is greatly appreciated!

[Randy S]

The correct approach would be to "Decouple" your wall if you dont have a staircase on the same wall.
The "Band-aid" approach below is not the best but, will deliver some relief if you cant afford to install a sound control wall system and decouple the wall.
Normally staircases share the same wall for both units and this is why the "Band-aid" approched is used.

[Randy S]

And yes floor to ceiling and wall to wall is required for results.

[badman70]

The correct approach would be to "Decouple" your wall if you dont have a staircase on the same wall.
The "Band-aid" approach below is not the best but, will deliver some relief if you cant afford to install a sound control wall system and decouple the wall.
Normally staircases share the same wall for both units and this is why the "Band-aid" approched is used.

Randy,

I'm still have some trouble understanding why It's so loud because the wall is already decoupled.  It's a double wall with a 3" airspace.  And 2 layers of 5/8 drywall on either side.  I can feel the vibration when they run up and down the stairs when I put my hand on the wall.  There are no materials that are continuous between the 2 units with the exception of the thin plywood subfloor because they can't have an air gap between the stories between the units.  The plywood has 2 saw cuts to decouple it under the base for each part of the double wall.  This wall is already supposed to be high 50's STC in the field.  I do know that the neighbors stairs are attached to their side of the double wall.

I have the same problem as the other poster in this thread as it is a 3 story townhouse. 

I still don't know what to do about the carpet as I will have to remove the molding on the wall, and the carpet tacks and pay someone to put it back together.  The cost of the green glue is going to be less than a tenth of the labor if I can find people to do this for me.  Then I'm worried after spending thousands   it might not work.

Dave

[Randy S]

Dave,
This is absolutely structure borne impact noise and you absolutely have a hard connection between units somewhere even with your double wall.
In your specific situation, the decoupling of their staircase is the correct approach and that does not sound like an option. I'm sorry to say, you are only going to be able to achieve a certain reduction based on dampening with "Green Glue". Filling the cavity with a blown in insulation might help with the "boom" sound in the wall if needed. Since your wall should already be 50 STC a dampener might be all you need depending on how many hard connections you really have.

If you would like, give me a call and we can dive into this further and see if we can figure out how it is traveling. Most likely you are sharing ceilng joist for the upper stories. You will need blueprints of your townhome for me to look at.
My information is below, I look forward to hear from you.