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Matt P
01-13-2008, 6:05 PM
This is kind of off-topic, but you guys are experts on construction, so I thought I'd give it a try.

I own an apartment with a very noisy upstairs neighbor. Building has cement floors. I understand that the only thing that really helps reduce noise is MASS. If I used some kind of concrete anchors to put a layer of cement board on MY ceiling, would the resulting thickness increase significantly help the noise? I could always cover the cement-board ceiling with drywall. Is this mechanically feasible?

Crazy, I know.
Tx,
Matt

Steve Leverich
01-13-2008, 6:23 PM
That won't help enough to even measure the difference in noise level - for a single leaf barrier (such as a concrete floor/ceiling) it takes DOUBLE the thickness to get a 3 dB difference in sound levels.

IF you have the ceiling height to spare AND the ceiling as built can support the extra weight, the most effective way to cut sound transmission is with a second leaf of mass suspended with isolated hangers, and standard fiberglass (not foam) insulation laid on top of the new layer. 1 or 2 layers of gypsum wallboard (sheetrock) makes a good second leaf.

For 'way more than you wanted to know about this, go here

Recording Studio Design Index (http://www.johnlsayers.com/phpBB2/index.php)

and read through the "stickies" at the top of the Construction forum. I've been studying acoustics/sound control off and on for over 20 years, and wrote the majority of what's posted there in the sticky section. Haven't had enough time lately to do that, but there are still VERY knowledgable and helpful people there including one (Rod Gervais) who is a professional engineer and has a book on Amazon titled HOME RECORDING STUDIO - Build It Like the Pros .

Whatever you do, find out EXACTLY how your ceilings are built before you decide on a course of action - otherwise, you may either get hurt/killed or at the least, disappointed in your results... Steve

Jamie Buxton
01-13-2008, 6:27 PM
You've got the basic principle correct: mass is good. Even better is isolated mass. Stuff called resilient channel has been the industry standard for decades. You fasten the channel to your framing, and hang the drywall (or cement board) on the channel. The channel provides very little bridging for conducted sound to get to the drywall. Google for more technical info. You probably can't buy resilient channel at your local Home Depot, but you will be able to find it at suppliers which sell to drywall companies.

As to using cement board versus drywall, it is a compromise between cost and workability. Whichever provides the higher mass, costs you less, and is easier to work with -- that's the one for you.

Mike McCann
01-13-2008, 6:41 PM
If yiou are in an apartment. Better check with the landlord about doing any major changes to the apt. They usually only allow painting what you are thinking about doing is pretty major change to the apt.

Jim Andrew
01-13-2008, 7:36 PM
Would not a suspended ceiling be a good way to eliminate noise? You said the floors are concrete, which are usually a great sound deadener compared to wood flooring. And if you don't own the building, I would check with the landlord. Jim

Mike Marcade
01-13-2008, 7:41 PM
How about quieting down the neighbor? You can use your imagination for the means of your choice. :D:D:D

Lee Koepke
01-13-2008, 9:04 PM
the RC channel and possibly a gypsum product "sound board" or the old name, homosite ???, then overlay with type c rated drywall.

building / fire codes come into play here as well. usually codes require one hour fire rating between dwelling units, and the entire assembly installed has to be PER the UL rating. modifying that system is not something to be taken lightly.

a local general contractor / architect / building official would be a good contact.

Andrew Nemeth
01-13-2008, 10:09 PM
Owens Corning (I believe) makes a whole line of products and describes methods for sound insulation for all sorts of applications. I used a product called resilient channeling that I screwed perpendicular to the joists in the ceiling of my basement shop. The drywall gets hung on this channeling and is allowed to "float". All the flat seams are taped and I cut the corners pretty tight and just caulked them with elastimeric caulk. When you push on the ceiling you can see it flex. This channeling, combined with their fiberglass insulation in the joist cavities has reduced the noise in the rest of the house dramatically. I can do everything but the loudest processes (surface planer w/ DC) almost anytime day or night directly under the master bedroom without any complaints.

I purchased the channeling at a drywall supply company and the rest of the materials at the BORG. I did the project and research almost 10 years ago so i don't know what is available currently. If you have any questions or need help tracking anything down feel free to ask.

PS- As a landlord I would be very hesitant to have just any tenant do this type of modification to an apartment. However, if I trusted the tenant (and I had a big enough security deposit), I would be delighted if they made this improvement. If they did a good job I might actually give them a discount on rent for a month or two for upgrading the property if there was indeed a sound problem. The point is, check with your landlord before doing anything. Make sure to get something in writing to protect you in the future or you may end up loosing not only your security deposit but you may end up in court for additional damages.

Chris Padilla
01-14-2008, 10:44 AM
http://soundproofing.org/

This site will make you dizzy but LOTTSA good info there.

Steve Leverich
01-14-2008, 5:19 PM
Chris, I hate to say it but people who actually study this subject (I know several) agree that there is more MIS-information at that site than there is fact. IF you check out the first link I posted you will find people who actually DO this for a living and know what they're talking about.

For example, Rod (friend of mine) builds professional studios for a living, and has been personally thanked by Steven Spielberg for building the quietest sound stage Steven had ever worked in. Another friend of mine who posts there regularly was responsible for the design team of the world's quietest recording studio - Galaxy in Belgium http://www.galaxy.be/

I know these facilities are far beyond the needs or budget of even "nawm's" place, but the principles of isolation remain the same, and they're NOT always intuitive.

Soundproofing.org is in the business of selling you as much product as you'll buy, and their recommendations typically prove this... Steve

Matt P
01-14-2008, 7:11 PM
Thank you - you guys are GREAT!

Ben Grunow
01-14-2008, 8:20 PM
Only thing not mentioned here is a sheet vinyl product which we use under drywall with good results. It is HEAVY. 33' roll is around 200lbs so get help. If interested PM me and I will get the name and mfgr for you as I have forgotten as usual.

Ben

Matt Mutus
01-14-2008, 8:21 PM
I just helped a friend soundproof a garage. He did a lot of research first and the options are many - he discovered it mainly comes down to your budget. The more you want to spend, the more options you have.

What we did is put a layer of regular sheetrock on the ceiling and wall, putting a silicone bead first on each stud. That was followed by a layer of MLV (mass loaded vinyl). The original plan was to put another layer of sheetrock over the MLV, but we might stop here, depending on how it works as is.

That is a heavy load so take care to accomodate it, we added cross members to the ceiling joists to support the weight.

What I learned in a nutshell are these guidelines: 1) decrease vibration at key points (structural members) 2) add density in layers (MLV is good at only 1/8 thickness) and 3) if possible get some air space in between two separate dense layers.

Not sure if that can help you, but he spoke with a few soundproofing consultants in his research - If you like I'll get their contact info.

Steve Leverich
01-14-2008, 11:22 PM
"if possible get some air space in between two separate dense layers" -

Matt, this is true ONLY if there is a TOTAL of 2 separate masses - as long as each layer is firmly against the next, these would only count as one "leaf" of mass, but the minute you leave even a half inch between layers, you LESSEN your isolation. The optimum use of mass (whether gypsum, concrete, MDF, Mass-loaded vinyl or whatever) is mass-air-mass.

Examples - a solid concrete wall with an air gap and 2 layers of gypsum wallboard (touching each other, but NOT the concrete) is a mass-air-mass construct. If you add another (touching the first two) layer of wallboard, you'll help your isolation. If you add another frame and another SEPARATE layer of wallboard, you won't see any noticeable improvement.

BUT - if you were to put ALL THREE layers of wallboard on the SECOND frame with nothing in between but fiberglass insulation, you would get the best isolation that's possible with that total amount of mass. The air/insulation gap improves low frequency isolation the wider the gap becomes.

If you can't use completely separate frames for the two centers of mass in either a wall or a ceiling, then one of the various resilient mounting methods is the next best thing - there is one called RISC clips that uses standard furring channels that is actually stronger and more foolproof than the older metal resilient channel that was referred to earlier.

This mass-air-mass principle also works for windows - a triple-glazed insulated glass window won't give as good isolation (especially at lower frequencies) as if you increased the mass of a double-paned insulated window to match the total mass of the 3-pane. The main reason for this is that air acts as a spring - and it's a fairly stiff one at that.

If you put a 3rd leaf of mass between two other leaves with air on both sides, you've effectively "shortened the spring", making it stiffer and therefore more coupled between masses. More coupling = better transfer, which in this case is BAD. Also, having 3 separate masses makes it a mass-air-mass-air-mass construct, which will have 3 effective resonant frequencies - one caused by the two outer leaves, one caused by leaf 1 and 2, and one caused by leaf 2 and 3. Any resonant frequency gets through the wall/ceiling/window better than NON-resonant ones, so now your wall has 3 weak points (frequencies) instead of just one.

There's a TON more to be learned on this, but it can all be found at the link near the top of this thread... Steve

Matt Mutus
01-15-2008, 12:43 AM
INteresting, thanks for the info - you clearly know more than me about this stuff. :)

Steve Leverich
01-15-2008, 1:25 AM
Thanks Matt, I'd be really depressed if I didn't - unless you've ALSO spent the last 25 years (off and on) digging into it :D and helping several thousand musicians worldwide in the past 4 years to build studios they'd never have had - those last 4 years were also a peak in my own learning curve, including friendships with several VERY smart people who were willing to share.

In spite of spending an average of about 20 hours a week helping others, I feel I got the better part of the deal every time someone finished doing what we recommended and were amazed that they couldn't tell a drummer was thrashing his kit on the other side of a wall, till they opened the door(s) and had to plug their ears :eek:

I've actually had a few people build spaces, then THANK me for badgering them to tear down entire walls and start over - the difference in isolation can be that amazing... Steve

Chris Padilla
01-15-2008, 10:22 AM
Good stuff, Steve. Thanks for the link. I WAS planning a master bath addition to my master bedroom (2nd story) and was seriously considering some stuff on the soundproof.org site. Unfortunately, bids came in about 50% higher that I expected so no new master bath! :(

I have your link added to my "sound" bookmarks for that one day in the future when I build my own home!

Matt Mutus
01-15-2008, 11:33 AM
Steve, since we're on the topic... maybe I can ask your advice.

The reason for my friends garage is my band need a new spot to practice. The inside wall touches the house, the outside wall faces the neighbor. The back wall has a regular door and the front wall is a retractable garage door. It has a peak ceiling sloping up/down from front to back. There are no windows.

The outside wall is concrete up to about 7 feet, then above that raw framing up to the peak. The ceiling is also just bare frame. The house wall is all concrete up to the peak.

What we've done is put insulation into all framed areas, then apply silicone to studs, followed by sheetrock then MLV. While the original plan was to add another layer of sheetrock over the MLV, we're now thinking of seeing how it works before going any further.

for the concrete wall on the house side, we are going to frame a wall 3-4 inches out and then hang sheetrock/MLV/sheetrock on that. We were also planning to do the same to the other concrete walls which don't touch the house, however we now want to test before going any further. There is not a lot of floor space so if we will avoid framing out new walls if we can.

My biggest concern is the doors, especially the garage door. The system will only be as good as the weakest link and this seems to be it.

My friend has made some hanging pieces that will block the doors when we play, I forget exacty, but the are mainly insulation and MLV from what I remember. He got this idea from a guy who was advising him.

1) for the bare framed areas, do you think another layer of sheetrock on top of the MLV will have enough impact to make it worth the trouble? or will it be a case of diminishing return give that it's a huge PITA to do it.

2) Short of buying a new garage door, do you have any tips to soundproof the doors, espcially the garage door. What ever is there has to be removable.

thanks very much - Matt

Steve Leverich
01-15-2008, 5:15 PM
Matt, this is a common problem with few workable solutions - here is one of the best, check a few pages either side of this one

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3876&postdays=0&postorder=asc&start=435

The basic concepts of sound isolation are

1. Hermetic seal (if it won't float, it won't hold sound in or out)
2. Mass - the more the better but ALWAYS in TWO places - no more, no less.
2-a. IF this isn't possible (like the garage door) then try to build your mass-air-mass construct as close as possible to the door, use an extra layer of mass (like 3 sheets instead of two) - the idea here is to minimise the "3-leaf effect" by beefing up the two leaves you have control over, thereby lessening the "3-leaf problem".

Avoid flanking - if your inner walls/ceiling cannot be separately framed, then using resilient mounts for inner wallboard (ALL layers) is a (very) second best. Best is a floated room-in-room, which becomes very math-intensive. Not recommended for less than high-budget with NASTY neighbors.

As to being able to breath in your hermetic room - check out the "stickies" at the top of the Construction forum, under "ventilation, poor man's air conditioning, etc." - the secret is long, large cross-section ducts with at least two 90 degree corners and fiberglass duct liner (such as JohnsManville "superduct")

I've probably forgotten to mention a few items - for a few evening's reading, here's the best place to start

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=2125

I've done several representative sketches on that site for different scenarios, but you can imagine that in 4 years they've gotten kinda buried - if, after reading thru the "reference section", you still have questions (I'm sure you will) post back here and I'll see what I can do.

It'll help if you can draw a sketch of some kind showing your walls, in enough detail to see where frames, panels,layers, holes, and insulation are located.

It'd also help if I knew whether you need to be able to actually OPEN the garage door or just "return the space to normal" after you don't need it for practice... Steve

Matt Mutus
01-15-2008, 5:52 PM
Steve thanks for the detailed response. I'll read through the material and see if I have any followup questions.

as for the garage door, it will definitely have to be opened to get our gear in and out between gigs/practice.

thanks again, Matt

Steve Leverich
01-15-2008, 5:55 PM
" as for the garage door, it will definitely have to be opened to get our gear in and out"

:(:(:(:(:(:(:(:(

I had ta ASK... you SURE there isn't another door for that? Durn... Steve

Matt Mutus
01-15-2008, 6:33 PM
well there is a back door but it's pretty thin. 28 inches I believe. Be a real pain to carry stuff around and through the skinny door. I'm not sure the guy who owns the house wants to permanently or even semi-permanently block off the garage door.

But it's his wife and kids on the other side of the wall, and his neighbors - so if he's happy I'm happy :)