Acoustical Surfaces – Soundproofing Blog

I have a psychological office in St. Louis. Mostly our clients do not talk loud, however, sometimes our clients are brain injured and they make quite a bit of noise. In other rooms, counseling might be going on. We are in a three story building with regular tiles above, and when we moved in, they put extra insulation over the wall joists, but I knew that wouldn’t do it.
We are getting busier, and I don’t know what to do. I’m thinking of white noise, I don’t know if we have enough money for new tiles, and I don’t think I want to chance the foam stuff that I would put in, instead of landlord, who would probably nix the whole idea. We have four offices that are affected, all about 9X12 or a little larger. Do you have any ideas or persons I could contact in st. Louis? Or types of companies? Or heavy materials that maybe I could put on top of the tiles between the rooms? I feel like I can only whisper when I talk about things/people because they might be able to hear us. Looking forward to your post.

C.C.
St. Louis, MO

The problem of the sound transmission issue is unfortunately a very common problem. I get calls all the time from people in similar situations who are looking for products to help stop sound traveling from one office or exam room to the other. Confidentiality and patient privacy is extremely important. Many people call me looking for a product to put on the wall, and because I have helped so many people, I start the conversation by asking three main questions.

1. Do the offices have the standard drop-in ceiling tiles? (The answer is almost always yes)
2. Does the wall between the offices go all the way up to the roof deck? (Most people don’t know and I tell them to pop out a tile and have a look)
3. Are there any air gaps around the door, between the bottom of the door and the floor or around the door jamb. If you don’t know, turn the lights off in the hallway and on in the office and see if any light leaks through. (Almost all of these doors have fairly significant air gaps)

When most office spaces are constructed, the contractors run the services along the ceiling, install the drop ceiling tiles and build the walls up to the ceiling tiles. From a construction standpoint, this is ideal, but from an acoustical standpoint it couldn’t be worse. The only thing that you have separating two offices that share a common wall are two ceiling tiles that are designed as an aesthetic barrier and to absorb some reverberation. They do not block much sound at all, it is not their job. The sound travels easily through one ceiling tile, over the wall and comes into the other office.

The door to the room is also a significant area for sound to leak into our out of the space. If ANY common air space is shared between one side of the door an the other, sound WILL leak through that gap. A 1% air gap in any kind of a sound barrier will leak 30% of the sound from one side to the other. Furthermore, a 5% air gap (ie: a ¼” gap between the door and the floor) will leak 90% of the sound through. Try it. Close your door and put your ear right where the door meets the door jamb. You might want to lock the door or block it with you foot so someone doesn’t pop you in the head trying to get into the room. Most of the time you will be able to very clearly hear what is being said on the other side of the door.

I’m sure you already have a pretty good grasp on the problem because it sounds like you have tried to take steps to fix it, but unfortunately the “insulation” on top of the ceiling tiles wasn’t quite the right product to do the job. LOTS and lots of people call me and tell me that this was their first step to try to soundproof the offices, but insulation doesn’t block any sound at all, it absorbs echo, but I can go into that later.

You’re probably sitting there saying “On with it, What products do I need!?”
If I were in your situation, I would order enough Barrier-Decoupler to cover all of the ceiling tiles and a Door Seal Kit to install on the door. You may also want to order a SoundScreen white noise machine. I would be happy to draft a quote for you based on the size of the ceiling, the height and width of the door and the SoundScreen machines are $69.95 each. I will go into the details about the products below.

The Barrier-Decoupler is designed to be a simple noise barrier. The product is 3/8″ thick, weighs 1lb per square foot and comes in two different roll sizes (54″ x 20′ and 54″ x 30′) (90 square feet or 135 square feet). It can easily be cut with a sharp scissors or a razor blade and simply put on the backs of the existing ceiling tiles. This will add a significant amount of weight to the ceiling, so if you have 2′ x 4′ tiles, I often suggest adding a T-bar cross beam across the center of the tile so that the existing tile doesn’t bow with the added weight. The Barrier-Decoupler has an STC rating of 26, which means that it stops an average of 26 dBa from passing through it.

The product is made up of a 1/8″ Mass loaded vinyl noise barrier adhered to an ¼” polyurethane foam decoupler. The mass and weight of the vinyl is the “active ingredient” and will stop approximately the same amount of sound as a typical wall. The foam is intended to touch the tiles and stand the vinyl off of the tiles and the track. This separation GREATLY improves the performance of the vinyl as it allows the vinyl to move. As the sound wave hits the vinyl, because of the mass and density, the vinyl will move very slightly transforming the airborne wave of energy into heat by moving the vinyl. The insulation that you installed does not have much density at all, it is mostly air. Because sound travels through air, sound travels through insulation.

The Door Seal kits are also a good idea when you are trying to stop sound. The kits are a retro-fit product that are designed to install onto the door jamb as well as the door itself. They provide a neoprene gasket to make the seal. The jamb seal is stationary and the door bottom is a spring loaded mechanism that closes to the ground as the door is shut. We offer two different kits, the Standard kit (1/2″ thick) and the Heavy Duty kit (7/8″ thick). The standard kit is normally installed onto a hollow-core door, and the heavy duty kit generally goes onto a solid core door. The difference is the amount of gasketing that makes the seal.

I commonly tell people to start with the ceiling and the door, and if the problem still exists to call me back and we can re-approach the situation. I rarely hear back from people, which is a good sign. Don’t get me wrong, I would love to sell more product but if the problem is fixed, and people are happy then I did my job. The nice thing about this is that out of all of the products that I have, these are some of the most cost effective. I like being able to tell people things like “let’s start with the cheapest products and work our way up if we need to.”

The white noise machine is also not a bad idea at all. You want to put this in the room where your “listeners” would be, not in the room where the noise will be made. The white noise machine will raise the ambient noise level in the room so that the sound coming from other areas are harder to hear. The sound that it makes is similar to a small fan or a small space heater running- kind of a whir or a hum, or a combination of both. Each machine covers a space no larger than 12″ x 12″. I could make all kinds of analogies here, but I think I’ve gotten long winded enough.

Again, I would be happy to put a product list together for you, figure out the cheapest way to get it there, and fax or E-mail a quote to you. You have provided me with the measurements of the room, but I would like to get the measurements of the door if that is a route that you want to look into. Unfortunately I don’t have any remote representation, but I have helped out enough people in similar situations that I feel quite comfortable helping you over the phone or E-mail.

Filed under:
Commercial, Office Acoustics, Soundproofing by Ted W