Soundproofing an Office Ceiling
I found your website and it has been very helpful. I’m hoping you can help us select the right products to solve a bad sound problem.
We are a CPA firm, and just moved into a newly built-out office suite. The total suite is 1700 sq. feet with 5 private offices. We have a terrible problem in that we can all clearly hear conversations in adjoining offices. We also have a bad echo in the offices.
Our offices have 14 foot ceilings, and the plenum above the drop down ceilings is another 6 feet. (We are on the first floor of a five story building, and the plenum above us is used to house lots of duct work, etc for the whole building. The return air is vented through the ceiling lights.
The walls are standard metal studs with sheet rock and insulation within. Our sense is that the sound problem is the ceiling. We looked at your Plenum Barrier-Sound absorber, but our contractor is concerned that it will be too difficult to install. The plenum is 6 feet high, and full of duct work, wiring, etc. He says it would be a huge “cut and paste job” and would wind up looking like a patchwork quilt.
We’ve also considered putting the Wall Panels in our offices, hoping that would absorb the sound before it has a chance to enter the plenum.
Any advice would be much appreciated!! I am a CPA and not a contractor, but our contractor really seems stumped.
Thanks for the E-mail. I can tell you that the problem is, in fact, the ceiling so that will be my area of focus. The ceiling treatment won’t help the echo problem in the room but taking care of that it really quite easy so we can deal with that later. It will probably be easiest to discuss this so please feel free to call me if you would like.
I have already talked to two people today about a problem very similar to this and have at least one other E-mail about something similar which means that I am going to draft an entry on my blog about this and publish it so others are able to get this information as well. I do want to put this out there right now- a drop ceiling is about the worst thing to start with when you are trying to block sound. I don’t mean to take the wind out of your sails or discourage you, but I need you to understand that for my own sanity.
Before you begin to look for options for blocking the sound, you need to find where the sound is leaking out, or leaking out the most. Without doing this, It would be like trying to plug a leaky fish tank without knowing where it were leaking. This can be done quite easily with your ears, and believe it or not, your eyes. I commonly suggest exploring this in two ways. The first would be to wait until the office is as quiet as possible (before or after hours) and get a radio or CD player as a good, constant noise source. Pick a song with lyrics rather than just music and put it areas in adjacent rooms. Go into the room in question and listen. Is it coming through the ducts, the ceiling, the cracks around the door, under the door, through the wall, etc. Trust your ear. The other way is to turn on the lights in every room around the room in question before going into the room and turn the lights off. Look for light. Where you have light leaks, you have sound leaks. IMPORTANT – Keep in mind, light leaks may be above the drop ceiling tiles, so take one of those out before you start.
Blocking sound is done by keeping three things in mind. (1)Common air space, (2)mass & density and (3)hard surface contact. These are the three ways that sound travels into or out of a room, and it works in that order. Sound is a lot like water, so visualizing water traveling in to or out of a room usually helps people understand this whole idea. The first thing above, common air space, is the FIRST path that sound uses, so this needs to be explored first. Believe it or not, if you have a 5% air gap in any kind of a noise barrier, 90% of the sound leaks through that air space. So, with this in mind, I would like you to explore three areas, the air gaps around the door, the HVAC system and the common wall (which will lead into the second).
Hopefully you were able to use the light test to come up with common air gaps. I would start there and fix those before treating EVERYTHING in the room. Chances are that this will not only be the most cost effective part of the whole process but it may reduce it to an acceptable level. Using my past experience and knowledge, these areas are just about always the air gaps around the door and the ceiling. We have a few different types of DOOR SEAL KITS that can be attached to just about any door and seal up the jamb (sides and top) as well as the door bottom. For the ceiling, you may want to look at the BARRIER-DECOUPLER which is the most cost effective approach by far but does not have a class A fire rating, our 8lb COMPOSITE ECHO ELIMINATOR which will not block quite as much sound as the barrier-decoupler but it is class A fire rated. Both of these would be put onto the backs of the ceiling tiles that you have now. IMPORTANT – Both of these options will add a lot of weight to the ceiling so you will likely need to add extra supports so that the ceiling does not fall down under the added weight. If you are looking for replacement ceiling tiles, you may want to explore the SOUND BARREIR ACT CEILING TILES which have the mass loaded vinyl backer but are by far, the most expensive approach. Ballpark prices (not including shipping or packing fees that may apply):
The one thing that makes this situation more difficult than most is the plenum return for the HVAC system. This basically means that there is no way to isolate the common air spaces between the offices which has a major impact on the final result. The only way that I have heard to help is to get an HVAC Contractor to fabricate and install “L” shape boots for above the ceiling tiles so that the sound being pulled from the room is forces to make a right turn. These boots are lined with our QUIET LINER which is a roll of cotton that has an antimicrobial facing on one side. This basically acts like a car muffler forcing the sound to pass by an absorptive surface.
I have not yet talked about the walls which I can leave for future correspondence if needed. I have helped quite a few people in the past do the best that they can with noise issues like this and always suggest treating the doors and the ceiling, and in this case, the plenum return factor and then use the offices for a week and re-assess the problem. The idea here is that you want to plug the biggest leaks first and then step back and see what you’ve done. It may be perfect and you can go about your business and it may need further investigation and treatment. With that said, I always suggest that people call me back if they need additional products or if there is something that didn’t work and I very rarely hear back from people which leads me to believe that the solution worked, or worked well enough to make them happy. In my business, no news is good news.