CEILING CONSTRUCTION OPTIONS. NEED HELP!

[aggybass]

Hi,

I was hoping you guys could help me decide on the type of ceiling to put in this studio.

Its a 20'x 20' detached garage that I am converting for a friend (in exchange for studio time and some cash).It will be used for recording a variety of bands from acoustic to rock. He is worried mostly about low
frequency noise escaping(neighbours within 50' of the garage), and to some extent, noise getting in from the outside world(aircraft, road noise).

My main concern is safety of the new room within a room structure, being that we are in California.Just had a minor quake this morning actually.

Drawing A shows a complete room within a room with a 2x4 ceiling built on top of the new interior walls.

Drawing B shows resilient channel on the existing 2x6 joists,which I'm guessing will give less seperation, but will be easier/cheaper to construct,
and possibly safer than having all that lumber built on walls that are only tied to the existing structure with swaybraces.

Main questions are as follows:

1) Will example A have a huge advantage over example B as far as seperation/soundproofing?

2) A, The longest span of any of the 2x4 ceiling joists will be 15'. Will this be O.K or will we need to attach some kind of bracing between the existing joists and the new 2x4 ceiling?

3) In either method, I will have to use sway braces on the walls. How many over a 20' wall if I use something like Knightfly's home-made sway braces?

4) In B, should I put anything between the top plate of the new wall and the existing rafter (neoprene/acoustic caulk), or just leave a small gap?

5) Quick floor question- I'm trying to do the numbers on how many neoprene pucks to use, but I'm still confused as to how many extra pucks to use where the floor is directly under the floor.Will the floor end up with
different amounts of compression all over if I'm not careful, leading to an uneven floor surface? Would it be better to build the floor inside the walls
instead? Oh, and I forgot to put on the drawing that the existing garage floor is concrete.

Thanks very much. Your advice is much appreciated.

AG

[aggybass]

Just found the span calculator,which answered a couple of questions already. I've looked through hundreds of posts, but always seem to miss the most important ones. Now I know I have to use 2x6 or even 2x8 for the ceiling joists, but that makes me worry even more about tieing the interior walls to the existing framing,with all that extra weight. It will mean a lot of sway braces, no?

Thanks,

AG

[knightfly]

There are a number of problems with your proposed construction vs. intent, some depending on hours of operation and others just won't make you happy with room sound, etc - I'm completely out of time for today, but will try to get a LOT more specific in the next day or two, sorry... Steve

meantime, check out some of Paul Woodlock's posts re: floating floors, why/how/why NOT - search on "weakest link", check out some of Dan Fitzpatrick's later links/posts, etc, these will give some idea of where I'm going with this... Steve

[aggybass]

Thanks Steve, look foward to hearing back from you.

Ag

[the dreamer]

That gets you started for decoupling/floating floors:


SOS link
http://www.johnlsayers.com/phpBB2/viewt ... 8574#18574
http://www.recording.org/ftopict-22542-hvac.html


Florian

Florian, I "crunched" your long link so we wouldn't have to scroll sideways for the entire thread - If you're not sure how to do this, PM me and I'll show you (I think it'd mess up posts if I put it here - Steve