HI,
I am trying to figure out the best and most economical way to sound proof hardwood floors. Its new constuction so I still have a lot of options.
I have done some research on underlays that may work as well as what can be done to the ceiling floor construction (insulation, resilient channels, double drywall etc.). However, there seem to be so many options, I can’t figure out which is the best.
Just wondering if anyone had some suggestions how to get the best results at a reasonable cost.
Thanks
Replies
No easy and/or inexpensive way. To prevent sound transmission, you need to 1. seal everything really well to prevent airborne transmission, 2. use dense materials (as much mass in the transmission path as possible) and 3. decouple layers of those heavy materials from each other with elastomeric layers. None of which is necessarily simple or reasonable in cost.
We have done projects with sound issues. You can use special drywall with metal in it. I seem to remember it was about $80 a 4x8 sheet. Steel and concrete floors are always better than wood on wood joists. Heavy tile on slide mat on thick cement board is very good. Dense carpeting on the noisy side absorbs sound at the source. So do drapes, cloth wall coverings and lots of fluffy furniture. Hardwood is not good for blocking or absorbing sound. Remember musical instruments are hardwood. Lots of sand in the sound path are one cheap material you could use, but it's not really practical for a floor.
If you must use hardwood, I would float the hardwood on an elastomeric membrane and use rubber gasketing or caulk around the floor edges. Keep in mind that sound is also transmitted through the wood structure around that floor (wall framing). Also warn customer not to expect too much.
If the sound source is mechanical equipment below the floor, it is best to insulate/absorb at the source and leave the floor alone.
DG/Builder
I am trying to do the same thing with walls. I happened across some cotton insulation that they claim works much better than fibrglass for found absorption. They are treated with boric acid for fire and bug prevention. They seem like they would work a lot better than fiberglass, not to mention that fiberglass is evil.
Paula
For the walls go with 1/2" soundboard each side 5/8" wallboard over that. I refered to an old building constuction textbook for that when I remodeled a police cheif's office. The studs are like strings being plucked when soundwaves hit them therefore the soundboard is first defense to soften those sound waves before they reach the studs and vibrate them. Insulation, by itself, does little since it's between the vibrating strings or studs. The insulation will slow transmission from wall face to wall face though, so I did both and it really works well.
Also, as was said the denser and more massive the wall, the less vibration and transference.
Thanks for the reply. We are planning 1/2" soundboard and then 1/2 drywall. You didn't mention the channels to help separate the drywall from the studs. Did you use those too?One side is tongue and groove and it is already installed. I plan to use acoustic caulk to seal up any holes created by electrical, lights, etc.I hope I'm not hijacking the original thread. I think the topic of sound transmission between walls and between floors is sufficiently similar. Paula
Edited 1/6/2006 9:37 am ET by Paularado
STC - is a rating system for sound tranmission control.If you do a google on STC Wall (ceiling) Assmeblies and STC Sound Control and the like you will get all kinds of hits that will show the specific differences between different methods.http://www.cwc.ca/design/building_science/sound_control/code.phphttp://www.stcratings.com/http://www.stcratings.com/assemblies.htmlhttp://www.quietsolution.com/Construction_Solutions/construction_solutions.htmlhttp://www.pac-intl.com/tests_wl_wood.htmlhttp://irc.nrc-cnrc.gc.ca/pubs/ctus/20_e.htmlhttp://www.cwc.ca/design/building_science/sound_control/floor.phphttp://www.pac-intl.com/assy_dwgs_fc_wood.htmlhttp://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/90246.htm
STC is a means to measure sound transmission but I'm fairly certain that STC does not account for frequences below 120Hz. Containing the base is far more difficult than the mids and highs.
From the first post I couldn't quite tell if the goal was to suppress noise from the floor into the space below, or the other way around. Both perhaps?
If you are set on hard(wood) floors then install some kind of isolation between the finished floor and the sub floor. Cork was mentioned but there are thinner materials available. This will lessen the impact noise transmitted to the space below. It won't eliminate it.
If you wish to reduce sound transmission from the space below to adjoining spaces, as was pointed out, de-coupling and mass are the way to go about it. Idealy, if you could build a room within a room, that would yeald the best results. Based upon the reading I've done I'll have to offer my disagreement on the use of sound board in any wall construction - you're better off with two layers of drywall, more mass. Agreed - insualtion does not to a lot, but it is not worthless either - helps contain the upper mids and highs. Apparently there is almost no measureable difference in the type of insulation to be used, fiberglass, cotton, old (clean) underware will all do the job.
If ya really want to know about sound control go over to http://www.avsforum.com, scroll down and find the "Dedicated Home Theater" forum, and read there. There's a couple of folks that really know the science beind this. Read anything by Brian R.
Dan
" but I'm fairly certain that STC does not account for frequences below 120Hz."Some of sources them also have inpulse ratings for floors.
Paula-
The info I had didn't suggest the tracks. After reading what I did I think I'd be worried that they'd be extra "chords".
De-coupling might be a better route than insulating; you want to install a low-density layer under the floor that is a poor sound conductor. Cork is one of the best, given its low density. Do a Google for cork +soundproofing.
Bruce
Between the mountains and the desert ...
I agree with ya on the cork there using it on the job I'm on right now---- million+ condos in a highrise.
Thanks for that info. I want to do some sound deadening between the basement and a first floor bedroom (the furnace noise is way to loud when it kicks on in the middle of the night) and was wondering if installing the cork on the bottom of the basement ceiling joists would work? And then covering that with drywall. Thanks.
How about containing or reducing furnace noise...would seem a lot simpler than treating the floor above.
Go down and listen to the thing when it starts. Is it fan noise, duct resonance, burner? All would be approached a little differently. As mentioned, the frequency (and that don't mean how often) would dictate ways to mitigate.
Surrounding furnace with absoprtion would be feasible. Think mini sound proof room. It doesn't even have to completely enclose the thing....just absorb radiated sound.
A pic might give more more to go on.PJ
Everything will be okay in the end. If it's not okay, it's not the end.
Let's say the cor would help, if it was covered with drywall. But Peter's simple idea...go to the source of the noise...is worth pursuing too.Bruce
Between the mountains and the desert ...
cork underlayment
ditch