Garage Conversion - How to deal with existing outer wall?

[BigGreenLamp!]

I'm in the beginning stages of converting a garage into a home studio. YES!!! DREAMS COMIN' ALIVE!

It's a quiet residential area, and I want to be able to record bands, so good sound isolation is my main priority.

I've been obsessively reading Rod's book, and all sorts of online forums and build diaries. I'd like to do this well, of course, so my first choice is to do 2-leaf MAM walls (Double studs, R-13 insulation, two layers of drywall per side with green glue in between). However, I'm not sure how to best do this on the outer walls, working within this garage space. The walls are aluminum (I think? Some kind of metal...), and have framework inside of it. Below are a couple of pics to show what I'm talking about.

So, my question is, how do I build a two-leaf wall system in here without having the outer frame and aluminum act as a "third leaf"? Is that something not to worry about, since the aluminum is rather thin and not really acting like much of a wall?

I'm wondering if, instead, it would be wise to beef-up the outer wall with mass (Drywall), add insulation, and use THAT assembly as the outer of the two leafs? Would it be a problem if the inner wall was the traditional 2-sheets of drywall, and the outer wall is a combination of aluminum and drywall? This would of course save my space and some material costs, although the outer wall would be thick (due to clearing the window frames), and I'd really have to pack in a lot of insulation to fill it up.

FYI - I'm planning on totally covering up the windows and garage door. I'd like to keep them, to keep the appearance of a normal garage from the outside, but have no problem blocking them from the inside to improve my sound isolation and to keep costs down.

Thanks, and I look forward to any advice!

[Dominick Costanzo]

You're fine adding mass to the first wall.
But how is that wall framed?
It doesn't look like the framing is on 16" centers.
You'll have to add to the existing framing if you want to use it as an isolation wall
You don't have to pack it full with insulation, just line it.
Skip the green glue.
What's your plan for the ceiling?
_________________
Dominick Costanzo

[BigGreenLamp!]

Yup, I'd definitely need to add to the existing framing. That's good to know about "just lining" the insulation, as opposed to packing it in there.

Why skip the Green Glue? Is it that you don't think it helps much in general, or that it wouldn't help THIS particular outer assembly?

My plan for the ceiling is level it off on the inside (As much as I'd love to keep the vaulted ceiling for the tracking space, I'm afraid it would be too hard to build a properly isolated ceiling assembly, with all the rafters and whatnot up there). Am I wrong about that? Leveling it would still give me approximately-10' in height. I'm thinking of doing single-stud assembly, 2 layers of drywall on top, insulation, then 2 layers of drywall on the bottom with Genie Clips/hat channel and green glue.

[Dominick Costanzo]

Green Glue isn't cost effective. Anywhere.
You could put up a 3rd layer of 5/8" sheetrock for much less and get better isolation.
_________________
Dominick Costanzo

[goose134]

Agreed on the framing concerns. Aside from the walls, if you want to hang 2 or even 3 layers of rock on the ceiling, you'll have to beef up the framing. I had a garage very similar to yours years ago. They do OK, but with the drywall you'll be hanging, they need help. If you're planning to cover the windows anyway, I'd frame another wall and rock it thrice. As for the ceiling, if yours is like mine, it'll be lumber every other joist spaced around 30" apart. You don't need to support the roof any more, just give the rock something to hang on.

Just nail up some lumber for rafters (2x 10's ought to do it) to fill in the gaps between the existing framing. Nail or screw in a stiffener and you're set. Stiffener is just a board that is nailed down to the top side to prevent wow and flex from the framing.
_________________
I make a living as an electrician, not recording in the basement.

[norton]

Green glue not cost effective? What? Please explain that to me.

From the extensive testing I've done in lab situations, the amount of mass and alternative construction methods necessary to accomplish the low end effectiveness of green glue far outstrips it's cost. In that equation I am considering both time, labor and materials...not to mention the amount of floor space the wall starts to eat up.

You don't need to use gg...but if you are really trying to keep sound out and in your room... You will want to use some sort of resilient clip and channel system.

The most effective (cost/performance/ease of use) are the green glue clips.

If you don't want to spend that much, you can go with a resilient channel....make sure it's the floppiest you can find. Home depot is unlikely to have the good stuff....look for drywall suppliers in your area, or industrial building suppliers. If you have trouble finding one go to www.thomasnet.com and use their industrial search engine to find something close to you.

That's one of the main keys to effective walls....making them air tight, but still floppy enough to move sympathetically.

Call up John Hile at The soundproofingcompany.com. He will be able to walk you through every step you will need to take to get the results you are looking for.

This area of the world is filled with bullshit, misinformation, and voodoo.... John has spent time working in a testing facillity, he knows what works and is on top of current changes in best practices etc. Good luck with the project! I hope it turns out perfect.

[norton]

Dominic....a single extra layer of 5/8 rock will not outperform green glue or a similar sound isolating compound sandwich of sheetrock. It just doesn't.

In the top end of the sound spectrum maybe the performance is close....but thats not the problem, low end transmission is the problem and Sheetrock alone can not match either green glue type products, or resilient channel assemblies.

[Nick Sevilla]

Hi,

I did the exact same thing to mine 4 years ago. I added a window, and used a double door, called a steel entry door, which has dpulbe glass, and insulated as well. Helps with the noise transmission. I recommend you replace your door with a better one, and that you keep one or two windows for fresh air.

I used :

Outer wall. 1950's original sheetrock.
2x4 lumber framing, original, and replaced what was too old.
Added 2x6 framing to ceiling, to hang the inner ceiling from, and allow space to run
Electrical for lighting and a ceiling fan.
1lb per square foot mass loaded vynil. Covered the framing of the walls and ceiling completely, as this was the only way to get a decent isolation without sacrificing the inner space.
Auralex RC8 resilient channels for mounting the inner walls, and ceiling. This was placed on top of the vynil, to mount a double layer of drywall. The drywall was mounted staggered, so the seams of the first layer got covered by the second layer, to reduce sound transmission.

I also installed floating floor, using 2x6 framing lumber standing on its edge, and using rubber U boats, to isolate the frame from the concrete floor. Mic cables and headphone sends were placed in the floor, and come up to three places around the studio, to minimize cable messiness. These come up to the console and patchbay.

I have pictures:
http://www.nicksevilla.com/nicksevilla.com/My_Photo_Albums/Pages/Studio_Photos.html

I used a licenced contractor for all the construction and electrical, so it is up to code. Check your local building codes and ordinances about modifying existing structures like a garage for other purposes. Make sure you know the laws, so you don't end up having to tear it down later, or worse.

Cheers
_________________
The Song. Nothing else really matters.