Caulking question

[Velvet Elvis 2]

Guys,

I read this: http://www.audiovideointeriors.com/inte ... ndex1.html where the person claims that he built a theater room using cement sealing caulk instead of acoustical caulk... any ideas as to whether this is smart?

Second, I read a thread that Knightfly commented in and he said it WAS NOT important to caulk around the framing of the rooms because they simply support the drywall. Can someone confirm or deny this?

I am building in a basement and am curious as to whether or not I need to caulk everything during the framing portion or whether I can wait (should wait) until I am drywalling.

Confused.

Jim

[SonicClang]

Caulk everything!!!! use a caulk that will remain plyable after it has dried. The combined effect of caulking everything will help reduce sound transmission between rooms. If a crack is too big to caulk, use great stuff, and then go over any remaining small crack with caulk.

There's no easy way around it, you must caulk. I've gone through hundreds, if not thousands of tubes of caulk during the 6 years of construction of my studio. Get used to it, you'll learn to love caulking.

[knightfly]

OK, first off why would you want to use a "maybe" product when the real deal is available for less than $5 per 29 oz tube just by looking around a bit? There's a REASON the stuff is called "acoustic" caulk by manufacturers...

Second, I stand by my comments about NOT needing to caulk EVERYTHING - the airtight seal needs to ONLY seal the innermost surfaces of the room together. IN fact, if we could be CERTAIN that EACH bead of caulk/backer rod would be perfect, there's very little reason (maybe a dB or two) to caulk anything but the LAST layer of drywall (although I don't recommend being this trusting )

Other than that, if your framing is going on concrete you need a thermal break; commercially available products go by names like "sill seal", etc - I've had good luck just using a couple layers of 30# building felt, but you need SOMETHING under the wall frame's bottom plate whether you're framing in wood or steel.

If you're still paranoid about caulk, you won't HURT anything by using it everywhere; you'll just waste time/effort/money that's unnecessary... Steve

[Velvet Elvis 2]

Steve,

Thanks for the reply... I'm actually very happy that I don't need to caulk everything (other than the drywall layers) as it saves me a ton of money.

As for the sill seal... what is the purpose of that?

The walls that exist already (framed when the house was built by city code) are just standard 2x4 walls on pressure treated sills... but they are on concrete.

Thanks again,
Jim

[knightfly]

With pressure treated wood you can get away with putting it against concrete, but I don't recommend it - remember codes are MINIMUM requirements.

In a perimeter wall, the sill seal is used to prevent air infiltration AND keep the concrete (which is in contact with the ground) from wicking heat out of the structure (energy efficiency) hence the term, "thermal break" - as in, break the thermal path - for inner walls, the main purpose is to isolate framing (wood or steel) from any source of moisture (the concrete) - but it would also lessen heat loss thru framing into the ground a small amount.

If you've not already found it, check out the couple of threads in the REFERENCE section on caulking, these should help clarify most questions... Steve

[SonicClang]

I wouldn't be so trusting with the caulking. There's no way I'd only caulk the final layer. What isn't blocked by the first layer of caulk, will hopefully be blocked by the second, and then there's the final one to block what's left. Once the walls are up you don't have a chance to caulk them if you think you've got a leak, so all I'm going to say is it's better to play it safe than to be sorry later. Do what you want though. Even the guy handing out the "only caulk the final layer" advice said himself he isn't that trusting.