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Soundproofing An Office Space

north star

Oct 19, 2009
& > & > &

I have an existing small office that needs to be soundproofed.

Currently, the plan is to remove the existing sheetrock walls and
install Sound Attenuation ( Batt type ) Insulation in to the walls
and over the existing L.A.T. ceiling, along with some sort of rubber
around the top of the walls where it intersects with the
L.A.T. ceiling.

I am asking for input on "How to soundproof" the single supply
air duct in to this office and the "return-air-into-an-open air
plenum"..........Noise is traveling mostly in & around the open air
plenum.......There are no plans to replace the 2 ft. x 2 ft. carpet
squares, ...yet !

Have any of you had good results in soundproofing the Supply Air
and Return Air from offices, or other elements of office spaces ?

Also, what about soundproofing doors , or around them?..........This
particular office has a solid core wooden door.

Thanks for your input ! :)

% < % < %
The best plan might be to take the walls to the deck above the ceiling. The return could be routed to the plenum through a transfer duct lined with insulation.


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If your not going to raise the walls to the deck then the return register should be attached to a length of flex duct that is coiled into a spiral. That is about the best you can get easily. are you trying to keep the noise in the office or out of the office?
Supply duct shouldn’t be a problem, it’s closed all the way back to the blower. Plenum return is your problem. I think JP‘s idea would work. It would be easy to try anyway.
If you don't extend the walls up to the deck you should at least lay some unfaced batt insulation over the ceiling extending 3 ft. each side of the wall.
M ~ M ~ M

Thanks to all for your input !

The intent is to have all of the noise remain in this one small office.
Adjacent offices have already complained.

Regarding the Supply Air ducting, when the air is on, the noise levels
are restrained [ somewhat ] from traveling upstream in the airflow.
When the air if off, then sound travels in to other nearby offices.

Paul, ...the current proposal is to install Sound Attenuation Batt
Insulation; such as the Owens Corning, Pink Next Gen Fiberglass
Sound Attenuation Batts, over the existing ceiling tiles and an
additional 3 - 5 ft. beyond.

The desired level of soundproofing has not yet been voiced by
Leadership........They just want the complaining to stop !

Q = Q = Q
I don't think your plan will get you more than 5 or 10 dB.

In the walls, I'd blow in cellulose and then hang another layer of gwb on resilient channels. I'll assume floor is a slab. You could put a floating floor in but last item. Extending walls to deck is a good option, but not easy to get everything sealed tight. Replacing acp with a drywall ceiling would seem simpler. Ideally hung on resilient hangers, 5/8 or double 1/2, and batts in top.

Try to eliminate back to back electrical boxes, and most definitely gasket door. Hopefully it's solid core and it gets closed. The number of my times we've addressed noise transfer only to learn they didn't close the doors.

Lined heavy guage duct for return - think periscope shape and at least 6' - and lined supply - better heavy guage metal. The flex let's the noise break out.

You might be well served by hiring an acoustical consultant who can quantify the situation and how much modifications will help, as well as give you someone to blame if it goes poorly. They probably can save you more than they cost. If I knew where you were, I might be able to suggest as someone. I've worked with many in US.
Before you go throwing money at the problem, maybe go in after hours, put a radio in the room playing loudly, and see if you determine where the sounds is transferring.
& * & * &

** bill1952 ** & ** e hilton **, ...thank you for your input !

bill, ...the location of the bldg. is in the Southeastern U.S..........Too many
eyes & ears to specify the location.

e hilton, ...I have walked by the office in question at various times and
the sound seems to be coming over the top of the wall and in to a
corridor, and "Yes, out the door", because it is left open.

Z - Z - Z
I know a person in Tampa area - former USG corporate acoustician - supervising all the testing at Riverbanks Laboratories and writing the manuals. PM me if interested.