airplane noise

cyeazel · Post by **cyeazel** » Mon Jul 11, 2005 10:35 pm

Hello. I'm Chris from Northlake IL (suburb of Chicago) and I have a quick ceiling question. After reviewing the refrence/temp FAQ section, I think it said no RC is better for low frequency isolation, which would include airplanes. Anyways, my existing ceiling is 3 inches of rubber with corregated steel underlayment and is 10 ft in height. I plan to rest my new 8ft ceiling on top of the newly framed walls (room in room) and my question is what is the best drywall combo to use?
Should I just do 3 layers of 5/8" drywall or is that not needed considering I'll have a 24 inch air gap between the existing and newly built ceiling?

knightfly · Post by **knightfly** » Sun Jul 17, 2005 6:49 am

Chris, welcome to the board; if you read the "before you post" sticky, it asks you to edit your profile to include a location. I know you said where you were from, but eventually those get "lost in the shuffle", unlike profiles which stay with every post - anyway, your question -

I would frame the inner ceiling heavy enough for 3 layers of 5/8, but initially only hang two layers - with separate framing, RC is totally unnecessary. I would also put at least 12" of fluffy fiberglass insulation between inner and outer ceiling, and if you can afford it a complete fill. Make sure any small cracks in the upper ceiling are completely SEALED with butyl (expensive) caulk or acoustic rated (cheaper but sometimes harder to find) caulk. This goes also for any other joints in the construction where sound can escape (or intrude) -

If you need help determining spans for different weights, post back with your span lengths and I'll help you calculate... Steve

cyeazel · Post by **cyeazel** » Wed Jul 20, 2005 12:52 am

Steve, thanks a lot for the reply. I've been wanting to find out about butyl sealant and it's acoustic applications so I guess it's good stuff seeing as you recommend it for the ceiling. I have an unlimited supply of it. I figured it had to be useful for something but I didn't want to use it until I was sure. So is it cool to use it (butyl) in other areas of the construction also (seams and perimeters of drywall etc.)? Oh yeah, I'll go and fix my profile.

knightfly · Post by **knightfly** » Wed Jul 20, 2005 4:06 am

Most likely the butyl you have is fine (for everything), but to be sure can you post a close-up pic of one of the tubes so I can see what it is? (please crop the unimportant parts and set size as close to 750 pixels wide as you can) Thanks... Steve

cyeazel · Post by **cyeazel** » Wed Jul 20, 2005 6:12 am

I can't post a pic right now because I don't have a camera. I do have a product data sheet though. The stuff I have is a premium grade butyl based sealant. It remains permanently flexible, tacky and resistant to moisture. It's actually comes in flexible rope gasket form instead of a tube, you just peel it and apply wherever needed. It is very easy to work with and to shape/fit for specific size gaps. It has a 99% solids content (ASTM D6), won't shrink or harden with age etc, etc, won't lose adhesion capabilities (ASTM C990). It is manufactured by ADCO products.

Does any of this info help? Is more needed? I can get a camera eventually, just not sure when.

knightfly · Post by **knightfly** » Wed Jul 20, 2005 7:04 am

A Part # or name would make it easier; only thing I found that sounds close to your description was this

http://www.adcoglobal.com/adcoproducts/pdf/WT64.pdf

Any more info available? Steve

cyeazel · Post by **cyeazel** » Wed Jul 20, 2005 10:29 am

Sorry Steve, I gave you the wrong link on accident. The correct address is http://www.adcocorp.com

The period at the end of the previous sentence and previous post screwed up the address. Anyway, the product is ST-30. Just type that into the product search and it should give you some more info on it.

knightfly · Post by **knightfly** » Thu Jul 21, 2005 5:50 am

Found the pdf specs finally; sounds like this stuff isn't real "squishy" - will you be able to force it into cracks OK, or will you need to be really careful to maintain a constant gap so it will work? Steve

cyeazel · Post by **cyeazel** » Thu Jul 21, 2005 6:16 am

It seemed pretty squishy to me. It's easy to resize and shape it to fit smaller openings if needed. But yeah, it is a thicker rope to begin with so I will need to resize it a lot of times. It's better to have to much sealant for cracks than not enough though right?

knightfly · Post by **knightfly** » Fri Jul 22, 2005 8:28 am

Sorta; but "just right" wins. One of the reasons the "Z" joints work better is that you get more than one try at sealing, so if one layer's bead leaks a bit there are 2-3 more to make up for it... Steve

cyeazel · Post by **cyeazel** » Tue Jul 26, 2005 1:49 am

Steve, I have a couple of drawings of my space. It might be kind of hard to read some of the text but the layout is clear. Should I post it or is it not worth it? I also have some pics on the way too.

knightfly · Post by **knightfly** » Fri Jul 29, 2005 11:35 am

By all means, post 'em - just remember to resize as necessary so they're no more than 750 pixels wide (not much smaller tho, or we can't see details :=) Steve

cyeazel · Post by **cyeazel** » Fri Jul 29, 2005 11:47 pm

Cool. I'll post some stuff as soon as I put it all together.