Soundproofing

charlesmd

Ive got a customer that I finished a basement for about two years ago and she has her bedroom directly over the basement bedroom. Shes been asking me about solutions for sound suppression. There isnt any insulation in the ceiling(I leave it as an option-she opted out). Has anyone ever used quiet rock? Is there something else I can advise her about. Ive got
a call in to my drywaller but I think hes out for a while(hunting season).
Thanks, Charles

genecarp

There are many options for soundproofing, had she opted for insullation, she probably would not be complaining now. if opening up the cieling is an option, open it and insulate, if not go over the sheetrock with 1/2'' ridgid insulating board, then sheetrock over that.

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AARC Drywall

I use the quiet rock on a houe, that was over 1.5 mill...the homeowner wanted all the basement done with it then 1/2" on top...
great stuff...also they packed in insulation before drywall...made a heck of a diffrence.

J

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Dougmt

I've heard good reviews of this stuff greengluecompany.com (need 15 posts to include the link) from the AV guys. It's an elastomer that is sandwiched between two layers of drywall. You've already got one layer up....
Doug

neolitic

Have had the best results with
resilient channel and 5/8 rock,
rigid fiberglass batts in joist spaces.

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James Boyd

I thought this was a good article. http://www.soundproofingcompany.com/...m_construction

I looked at quiet rock but my jobs can't afford the cost. I've used the green glue and I read somewhere the test differences between the two. When I assemble 5/8 rock and greenglue it's fast. I use the pails now and a gun they provided.

Anyway, I reached the idea that the greenglue was better and cheaper, and I have more billable labor

James Boyd

Neo when you say rigid insulation, are you meaning foam panels? I read a really interesting post somewhere sometime that nothing beats batt fiberglass.

EDIT: I see you said rigid fiberglass

BUTCHERMAN

Insulating does nothing for sound. If you can't afford quiet rock then I would suggest doubling the ceiling. Layers of rock provide sound proofing more than insulating. I've done a lot of theatre rooms in homes and quiet rock does work best. But at $100 for an 8x4 board plus the caulk it's ridiculous. Now they make this flannel stuff that is suppose to work good. But I don't how good it is or the cost. I do know it throws off the ceiling when you rock over it.

genecarp

http://alsnetbiz.com/homeimprovement/faq10b.html check this out. G

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James Boyd

Insulation provides some improvement. Not as much as the mass of drywall, but a wall tested with it does better than without. I think the problem is that people rely on it as the big answer.

You should seriously look at the greenglue. I did the math and reading a while ago. Cheaper than quiet rock and tests better.

The flannel stuff I think is the recycled blue jean stuff. I have bid that twice, but no actual job yet. I'm anxious to try it, although it doesn't work better than fiberglass. Dow has some recycled polyester also that I saw but never tried yet.

James Boyd

I started looking at that link, Gene, but they're promoting a soundproofing paint, it looks like. There is no such thing, so it makes me wonder. Also the "really, really serious" diagram he has is a waste. Resilient channel on a second stud wall is redundant.

It's cool that you posted some help, don't get me wrong.

neolitic

There is this:
http://truesoundcontrol.com/products...FQykagodZj8Fyg
I've bought the same thing cheaper
from JM,or OC, can't remember right now.
It's much more effective than fluffy
insulation batts.
Two layers of 5/8 on resilient channel will
give the greatest effect for the buck.

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BKFranks

Should have put sound attenuation batts in there. Something like Thermafiber or Owens Corning. Since it's a basement you might want to minimize the amount the ceiling is dropped using resilient channel and another layer of drywall. So the insulation should have been tried first. Is there carpet on the floor upstairs? That helps to minimize the sound compared to a hardwood floor.

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charlesmd

The fly in the ointment here.... No there isnt carpet above, its hardwood flooring. I also didnt mention the sprinkler head in the bedroom in the basement.
Sorry about that, still havent heard from my drywaller. If I add drywall(another layer) the head would be concealed or the flow impeded, Frederick City md is real strict about fire code.I wont be drawing a permit for this anyway, but dont want to interfere with the sprinkler head. I guess the bottom line here is what shes willing to pay to have it done correctly. its all on her, I did give her the option before..I like the option of quiet rock but dont want to get her hopes up spending all the money to do it then find out its not enough. if I dont here from my drywaller soon, Im gonna go piss on his cmere deer and yank his ass out of the tree...(Iknow where he hunts).Thanks for all the input, ill let you know what happens. charles.

James Boyd

Neo, those panels don't work any better than fluffy fiberglass. I'm sorry. I went down this same road a year ago asking questions on forums where recording studio and theater designers hang. I was clobbered with lab info. Piles of it.

The panels you linked perform the same as R19 when installed IN an wall or IN a ceiling.

Charles, you can:

lower the sprinkler heads
install some drywall channel and clips
R19 fiberglass
double 5/8" rock.

Or you can actually install drywall strips and glue to the bottom of the subfloor. There's an article online about this. It stops a lot of the vibration before it even gets into the framing.

James Boyd

Franks, the RC channel on top of an existing ceiling will trap a small air cavity and make a disaster

neolitic

That must mean that you know something
that no sound engineer or recording studio
designer knows.
Care to back it up with actual published
controlled studies?
You can't do it.

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James Boyd

Not looking to argue. As I said, I looked into all of this in detail a year ago.

Look at research done by the NRC in Canada. Largest scale, most distinguished acoustics lab in North America, if not the world.

One study they conducted was IRC Internal Report IR-766
April 1998.

Consider these 2 floor tests:

#TLF-95-085a 90mm Fiberglass Batts STC 51
#TLF-95-065a 90 mm Rock Fiber Batts STC 51

What these test numbers (STC) don't show is that the fiberglass actually has a slight edge in the lower (bass ) frequencies. Since low frequencies are what we wind up hearing most of, it is most advantagous to use fiberglass over mineral.

Having said all of this, here's a quote from that report:

"Putting sound absorbing material in the cavity of a joist floor with a ceiling that is not resiliently suspended provides no significant increase in sound insulation."

We might argue that a little, but the fellow is saying that insulation makes a big difference if you are using double stud framing, or resilient clips, even resilient channel. Insulation makes a more minimal difference in a standard wall or ceiling.

neolitic

Which is pretty much what I said.
Isolation and absorption.

I've never done a recording studio,
or radio broadcast booth where
they speced fluffy batts, it has
always been rigid.

The best thig the guy could do
is hang the ceiling in 1" sheet lead.

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James Boyd

If anyone's using rigid batts, they're spending more than necessary. That was my point. It's a shame this information isn't talked about more, but I guess we can't rely on the manufacturers to point this out.

Also, there's nothing wrong with more expensive insulations, per say. They're just more expensive is all.