As I tackle this topic about soundproofing a room with egg cartons, my immediate thought is ‘Who would do that?’ And ‘Why would someone do that?’ And ‘What would make anyone think it works?’ (Also, probably, ‘What are they smoking?’) After a little research I have the answers.
Keep in mind that sound is a combination of Impact Noise (something hitting the wall or floor) and Airborne Noise (sound traveling through the air). It is also important to decide whether you want to stop the sound from leaving the room or stop the noise from entering the room–or both.
Why use egg cartons for soundproofing?
Good question. Egg cartons resemble the shape of some acoustic foam panels like the JBER acoustic panels. I am sure that gave someone the idea to use egg cartons. They are plentiful, inexpensive (you already paid for, and used, the eggs), and it gives a person a feeling that they are recycling.
And it is relatively easy to assume they will work–if shape is the main determining factor. Someone with a limited budget, or someone with a serious interest in Reduce, Re-use, Recycle, can be excused for coming to the conclusion that egg cartons will help soundproof a room or reduce ‘common wall’ noise.
I have seen pictures of them painted and arranged on the walls in different designs. This provides the option of being able to change the design or color without re-painting the walls. On the other hand, your wall will probably be left with glue spots (or spots where the glue pulled the paint off), or many small holes made by the push pins used to attach your egg cartons to the walls and/or ceilings.
Do egg cartons for soundproofing work?
In a word ‘No’. I might define soundproofing as ‘A science based creative art used to provide peaceful surroundings’. Egg cartons can be made to look creative but their only acoustic value is to reduce echo in a narrow sound range band. As for keeping noise out, or keeping sound in the room–they do neither. Nick Colleran at Acoustics First had a lab test done on egg carton acoustics. You also may also be interested in an egg carton acoustic myth busting YouTube video.
Can they be made to work better?
They would probably work better if you left the eggs in them. That would at least provide more mass. Materials with higher mass cut down on particle vibration necessary for sound. People have doubled up the cartons trying to make them more efficient, but they are still a porous material with very little mass that does little to stop, or absorb, sound. Quite often the ‘law of diminishing returns’ takes effect when you start with a bad idea and spend more time and money trying to improve it.
Alternatives to soundproofing with egg cartons
Now that we have exposed the egg carton myth, we can look at some soundproofing ideas that actually work. As always with soundproofing, you must answer the ‘keep the sound inside, or keep the noise outside’ question. Bathrooms (Please see our article on How to Soundproof a Bathroom.), and your kid–the next great rock ‘n roll drummer–are ‘keep it inside’; while car alarms and traffic noises are ‘keep it outside’. Because of the egg cartons, I will assume the room is a music studio or home entertainment room, and make some suggestions for those applications.
Installing ‘real’ soundproofing panels
When soundproofing a room (or most anything else) the goal is to achieve the highest STC (Sound Transmission Class) rating possible. I have included the following chart from Wikipedia Sound Transmission Class along with this link to give you more information on STC than you ever wanted. It will give you some idea of what to expect, and what you are trying to accomplish, when soundproofing your room.
|STC RATING||What can be heard|
|25||Normal speech can be understood|
|30||Loud speech can be understood|
|35||Loud speech audible but not intelligible|
|40||Loud speech audible as a murmur|
|45||Loud speech heard but not audible|
|50||Loud sounds faintly heard|
|60+||Good soundproofing; most sounds do not disturb neighboring residents.|
Soundproofing expectations and needs are fairly personal preferences. How much, and what kind of sound is too much? For instance, I can sleep through all but the most violent thunderstorms, but I find that hearing the tap dripping is crazy-making. Do you own the house? How much do you want to, or are you willing to, spend? What is a reasonable balance? In a previous article, (How to soundproof a bathroom), I talked about removing drywall to the studs and sub-floor to the joists. Assuming that the egg carton idea is a hint about either finances or lack of aggressiveness, here are some suggestions for soundproofing the walls and/or ceiling. In no particular order:
- Acoustic Paint – Coat of Silence sound deadening paint by Acoustical Surfaces Inc. claims to improve your room’s STC rating by 2.3 – 3.0. It sounds great but I have zero experience with the product. Don’t even know anyone who has used it. Kind of sounds like egg cartons to me. If you are interested, take a long look before buying.
- Acoustic Wallpaper – If, like me, you consider wallpaper something that comes in a roll, then this also kind of sounds like egg cartons. But if we include some Google results (such as Bubos Acoustic Panels) for what I call panels (with many attractive finishes), they will have some value at soundproofing. The Bubos panels have an NRC rating of 0.9. They are attached with 3M Heavy Duty double sided tape, 3M spray adhesive, or they can be screwed on. They are only 4/10″ thick and have the added advantage of being flame retardant.
Note: NRC (Noise Reduction Coefficient) is a measurement of the amount of sound being absorbed in a room. (Please see Wikipedia – Noise Reduction Coefficient for an ‘in depth’ explanation.) It is a rating range from 0.0 – 1.0. The 0.0 rating means that no sound created inside the room is being absorbed. 1.0 means that all of the sound created inside the room is being absorbed. For example: If the NRC rating is 0.75, then 75% of the sound is being absorbed by the panels and 25% is reflected back into the room.
- Pyramid Acoustic Panels – Because they are shaped somewhat like egg cartons and that is, after all, what we started talking about. These are 2″ thick foam panels made to absorb sound. They can be attached to your wall with glue, double sided tape, Velcro, or even stapled to the walls and ceiling. They are used in recording studios or media rooms because of their sound absorbing qualities. But you can also use them in any room that you are trying to make quieter. Their NRC rating is approximately 0.65.
- Sorry, I cannot resist another shot at something that resembles an egg carton. I would go for the Bubos panels every time over the Pyramid panels. The Bubos have a better NRC rating and they are way thinner–so they do not intrude into the room near as much. And, because they are made of 100% polyester instead of foam, they not only absorb sound created in the room, but provide some soundproofing for noise from outside of the room. They will cost you a bit more–but in this case, I think you get what you pay for.
- Furniture, Pictures, Wall Hangings, and Carpet – I am certain that you have experienced the sound in an empty room. It echos and reverberates. Once the same room is furnished, the sounds will be greatly diminished. So, if at all possible, add furniture to the room, hang pictures, or other types of wall hangings, and carpet if the existing floor is hardwood or laminate. The heavier, thicker, and more solid–the better. All of these will add mass to the walls and room in general which absorbs and dampens sounds.
- Sound Absorbing Blankets – If you want a quick and relatively easy way to absorb sound–consider blankets. Basically there are 2 quality levels. You can use heavy-duty moving blankets with an NRC rating of 0.3 – 0.5 or acoustic quality blankets with and NRC rating of 0.8 from Vocal Booth to Go. Essentially you are going to cover the walls in the room with these so buy some with grommets for easier installation. A couple of things to keep in mind–you will get a better result if they are 3 inches away from the wall, and an even better result if they are pleated. So if you are willing to lose up to 6 inches of space on each wall, it is well worth considering. (You will have to hang them on rods–not just nail them onto the wall.)
- Drywall and Green Glue – Now for some serious soundproofing. Most of the above suggestions are about adding an inexpensive, and non-intrusive, treatment to the walls of the room. They absorb sound and/or diffuse sound from inside the room. If you want to try to eliminate sounds from both inside, and outside the room–and do not mind spending more time and money–give some consideration to adding another layer of drywall throughout the room complete with Green Glue sandwiched between the existing drywall and the new layer. This will give you an STC rating of 43. (Go to Green Glue Company for more information and an installation video.)
You will need approximately 2 tubes of Green Glue for each new sheet of 1/2″ drywall installed. Remove all of the furniture, baseboard, casing, and wall hangings. Put the Green Glue on the backs of the new drywall and install over the existing. It is best to avoid having the new drywall joints line up with the existing ones. Tape the drywall and paint. You will have to extend the door and window frames by 1/2″ to get your casing to fit properly. Also extend any electrical boxes. The chart below (from Wikipedia Sound Transmission Class) shows that you will increase the STC rating from 33 to 43.
|27||Single pane glass window (typical value) (Dual pane glass window range is 26–32)“STC Ratings”.|
|33||Single layer of 1/2″ drywall on each side, wood studs, no insulation (typical interior wall)|
|39||Single layer of 1/2″ drywall on each side, wood studs, fiberglass insulation |
|44||4″ Hollow CMU (Concrete Masonry Unit) |
|45||Double layer of 1/2″ drywall on each side, wood studs, batt insulation in wall|
|46||Single layer of 1/2″ drywall, glued to 6″ lightweight concrete block wall, painted both sides|
|46||6″ Hollow CMU (Concrete Masonry Unit) |
|48||8″ Hollow CMU (Concrete Masonry Unit) |
|50||10″ Hollow CMU (Concrete Masonry Unit) |
|52||8″ Hollow CMU (Concrete Masonry Unit) with 2″ Z-Bars and 1/2″ Drywall on each side |
|54||Single layer of 1/2″ drywall, glued to 8″ dense concrete block wall, painted both sides|
|54||8″ Hollow CMU (Concrete Masonry Unit) with 1 1/2″ Wood Furring, 1 1/2″ Fiberglass Insulation and 1/2″ Drywall on each side |
|55||Double layer of 1/2″ drywall on each side, on staggered wood stud wall, batt insulation in wall|
|59||Double layer of 1/2″ drywall on each side, on wood stud wall, resilient channels on one side, batt insulation|
|63||Double layer of 1/2″ drywall on each side, on double wood/metal stud walls (spaced 1″ apart), double batt insulation|
|64||8″ Hollow CMU (Concrete Masonry Unit) with 3″ Steel Studs, Fiberglass Insulation and 1/2″ Drywall on each side |
|72||8″ concrete block wall, painted, with 1/2″ drywall on independent steel stud walls, each side, insulation in cavities|
- Drywall and Mass Loaded Vinyl – Mass Loaded Vinyl (MLV) is one of the products at the top of the soundproofing heap. The one pound per square foot product recommended for walls will give you an additional STC rating of 26. So added to the nominal STC of 33 of your existing interior wall, and with another layer of drywall, you will achieve an STC rating of 60+ (please see charts above). You are getting into the ‘virtually soundproof’ range.
Before adding the MLV to your walls add 1/2″ furring strips to each stud, then the MLV, then another layer of drywall. Tape and paint drywall. Extend door and window jambs, and electrical outlets. Then re-install baseboard, casing, and fixtures. This is the costliest option I have presented–also the best.
Keep in mind that you do not have to soundproof the entire room. If you only have one wall between you and your kid, and she/he is complaining that your ZZ Top is too loud–just do the one wall. Or suggest she/he move out and get a job.
Because I come from the ‘glue it and screw it’ school of construction, and because this stuff is heavy, and because poop happens, I would install a crown molding at the top of the wall against the ceiling and over the MLV to hold the top in place–just in case gravity works, and it wants to peel down from the top.
Soundproofing floors, doors, and windows
Although you can attach egg cartons to your doors and windows–if you are really determined–using them on the floor just will not work. The quickest and easiest cure for the floor is an area rug. It will cut down Impact Noise such as footsteps or something being dropped. It will also absorb some of the Airborne Noise because of its mass. You can also add a soundproofing mat under it.
For the door you can use any of the suggestions listed above. Just attach whichever product you chose to the inside of the door slab. You can even do the same thing with windows if natural light, or ventilation, are not major requirements. But short of replacing the door slab with a solid core door, weatherstripping, and all of the extra work involved (see How to Soundproof a Bathroom), and replacing the window with a triple glazed unit, your best options are soundproof curtains. Heavy and thick will almost always block, or absorb more sound.
One option is black-out curtains. You can find them in many colors and they have the added advantage of preventing light coming in the windows or around the door–if darkness is important to you. They are usually heavier than standard curtains so ensure that the rods you are using are well secured. (Note: If there is no wood backing at the locations where you want to attach the rod, give some consideration to installing a pine or oak board above the window or door. Make it wide enough and long enough to so you can find solid framing to screw it to. Once it is solid you can attach the rod wherever it works best.) The Moondream 3 in 1 curtain claims to reduce sound by 7 decibels.
An even better option is a curtain made with mass loaded vinyl available from Residential Acoustics. They have an STC rating of 26. These curtains can be even heavier than black-out curtains. (MLV weighs one pound per square foot.) Some of these curtains come with Velcro or magnetic perimeter seals; making them even more efficient at reducing Airborne Sound from escaping the room or intruding into the room.
Note: Make sure when installing your door curtain, that it can be moved completely out of the way. If it is a sliding curtain, the rod should be long enough to ensure you are not having to push it aside every time you go in or out. If it is a roll-up curtain, it should roll high enough that the door does not hit it. You will certainly need your wood mounting board for this application because you will be attaching the curtain well above the door header–if there is one. For best soundproofing, your door curtain should touch the floor. Touch–not drag or fold.
Although my wife went to university with someone living in an old bus who insulated the entire thing with egg cartons–and survived while getting a degree–I suspect it was a ‘hippie thing’. Quite possibly drugs and alcohol were involved. Egg cartons will do nothing for either insulation or soundproofing–but in the case of the bus, they will provide Glory Days conversation.