Soundproofing an existing ceiling

cwest54

I have a brand new drywall and plaster ceiling that was put right on top of the ceiling joists with a dead space all the way up to the subflooring of the second floor. Voices in the room above are not a murmur; you can practically make out what they are saying. I don't want to to have to tear down the celing and start over. Would spraying insulation foam into this cavity do a good job of dampening the sound?

Just Bill

Soundproofing after the construction is a tricky thing. Adding insulation may work wonders or it may do nothing. The type of insulation is often more important. There is a new product, 'Roxul', that claims superior sound proofing. I don't think it comes in a blow in version.

rightit

You'll likely not only have problems with voices, but also impact sound. Insulation will help to a certain degree and within certain frequencies, but there are several elements that are essential to soundproofing. My recommendation is that you understand what sound you need to diminish and how best to accomplish it, as it's easy to spend the time and money launching a solution only to find it doesn't meet your expectations. Soundproofing can require expense and effort. Best to go with what is right the first time.

These links to article libraries will provide you with some good information covering the problems of soundprrofing and how to solve them. They sell soundproofing products, but I have found their information to be objective and accurate:

http://www.greengluecompany.com/technicallibrary.php

http://www.soundproofingcompany.com/library/articles/

http://www.soundproofing.org/

Ted White

You definitely don't want foam. About all you can do is to add more mass and damp that mass with damping compound. Standard 5/8" drywall is heavy and cheap.

Insulation will help a bit but only if is of low density. Higher density will risk conduction. This is a real risk with anything blown in.

Stanchek

Just a thought. What is the flooring upstairs? Maybe some carpet with high density pad? Also a thought, though it requires a bit of work. A drywall overlay on the existing ceiling. I did a very expensive condo job where the customer had us do 3 layers of drywall on walls and ceiling. And let me tell ya, that place was soundproof. Just some thoughts.

fixrite

There is also a drywall sound board that is equal to 8 sheets of drywall for sound dampening. Sound deadening and sound proofing are looked at as two different kettles of fish. You would most likely benefit from installation of both sound deadening drywall and roxul insulation. Did my basement that way and huge difference. Kids can play pool as well as video games on the big screen and we don't hear them at all. But we can listen in on them with the intercom system and that makes for a fun time once in a while.

Ted White

That is a myth, actually. The board is a fine (albeit expensive) product but there has never been any test data or even a theory that would support 1=8. It is a marketing sound bite. Nothing more.

fixrite

Yes it is expensive, but that is based on opinion.I do not wish to argue about just how many sheets of regular drywall this is equal to,all I know is it works and he was looking for a solution. NO myth there.

Ted White

No myth that pre-damped drywall can work well. I was speaking specifically to the marketing sound bite which is unfounded and therefore misleading.

fixrite

You say it is an unfounded and misleading but those are just general derogatory statements, with no supporting documentation, sounds ( forgive the pun) like you are doing exactly what you accuse the other company of doing........hmmmmm

Ted White

You're not acquainted with the industry, so I can appreciate your perspective. They've been called out on this for many years within the acoustics community.

It is unfounded if there's never been any supportive documentation or dialog. Try asking them as many others have.

The continued use of the sound bite without supporting documentation would be considered misleading by most. The burden of proof is upon them, not me.

fixrite

Acquainted with the product I am. Just as I am acquainted with other products. Although I may not know the exact specifics on any one product does not make me ignorant. Although some may think they know it all about everything, I do not. I stand by my statement made earlier, using roxal and sound deadening drywall works. There are many other products out there that do a very good job and need to be installed differently as they are a different product. Some are better than others which is par for the course. Seems like you have a bad taste for a specific product, I did not mention brands or anything of the sort. Only trying to offer a reasonable solution to a challenge someone was having. I think at this point I should look at fixing the in floor heating of my igloo as it gets cold here in Canuck land.

Ted White

PLease don't take this the wrong way. No one said you were ignorant.

Of course Roxul and pre-damped drywall can work well. No one said it did not.

What I have a bad taste for is any company that preys on someone's intuition rather than relying on industry standard independent testing to forward a point.

kranabetterp

I need to soundproof my ceiling. Although this is a diy site I was hoping someone would know if I hire a general contractor or a drywaller to take down my ceiling/add roxul instillation/resilient channel and then drywall. I have read that it is tricky to put up the resilient channel properly. Thanks.

Ted White

Resilient Channel is not only tricky, is mis-installed more times than not. 85% according to the companies that manufacture it. It has no structural rating and anyone who bends steel is free to make whatever they like for a profile. THis is why it is the #1 soundproofing product in litigation. It simply does not deliver.

I would suggest you focus on getting a good drywall guy. The finishing of the drywall (mud and tape) is technically the most difficult part of all of this. Then simply give him the plan of what to do.

http://www.soundproofingcompany.com/...fing-ceilings/