Low budget garage conversion for mix and overdubs.

[trodden]

Hello everyone. First off, I've learned a lot from this forum over the past 7-8 years it's been around. The last two studios I've owned were constructed from what I've learned here, even though each of them had some severe corners cut due to budgets and them also being in rentals. I had really hoped that the next time I was here poking around on this forum, I'd be an actual property owner and finally starting to plan out my dream studio and never have to deal with it again…

Well, that's not the case. I, along with many other people, was finally priced out of Seattle which has changed drastically over the last 4 years, much like San Francisco and Oakland due to the tech industry. When my landlord said he wanted his building back, I couldn't afford something similar in Seattle as a renter or buyer since the real estate market has changed so much over the 6 years I was in my old building. With 60 days, and with little options, my fiancé and I decided to head south to Tacoma, WA where there's still cheap rent and the possibility of actually owning something. Seattle has become so expensive that owning a house or a building is now out of the question for our incomes. So here we are, in a rental house with the plan of being in it for two to three years while we continue to save and either buy in Tacoma, or buy somewhere else affordable if Tacoma doesn't work out for us for whatever reason.

I left thousands of dollars worth of construction in my last place. I don't really feel like doing that again since I know this will be only for a couple of years. I looked at the option of renting a rehearsal studio to throw all my gear in, and that would be a monthly rent of $250-$400. I already pay monthly rent in Seattle for a rehearsal space for one of the bands I'm in and there isn't room to move a small studio in as well. Plus rehearsal spaces have poor isolation between the rooms. Instead we found a small house with a small detached garage in the back. I figured I could spend X amount of money on making it useable which would still be cheaper than paying a monthly rent on a rehearsal studio for 2 years. And I'm finding that I'm going to have to cut even more corners this time.

There isn't much to this structure. It's just a wood frame with two layers for the outside skin (with tar paper between the two layers) on top of a concrete slab. It's cold, and when the radio is loudly playing inside, I can hear it pretty well on the outside. It's also not very secure. So yeah… bleak.

My goals: Create a space where I can mix and do overdubs. Keeping the heat and sound in as well as offering some security to my gear. I will not be tracking full bands or drum kits. I will be using other rooms, commercial facilities for full band tracking and taking projects here to finish. There will be electric guitar, bass, vocal, key overdubs. I'll also use the place to work on my music which will entail practicing and composing bass, guitar, and keyboards. I'm willing to turn down my volume levels after 10:00 p.m. in order to comply with noise ordinance in trade to spending money I don't have or want to lose on the build out. However, I'd like to be able to mix at a useable level, without headphones, after 10:00 P.M. When I do move out of this place, I will need to easily convert it back to an operating garage.

My Plan: I will be splitting the 20' 9" X 15' X 8' (inside dimensions) into a 11' 5.5" X 15' X 8' work space and a 9' 3.5" X 15' storage area since our tiny house has very little storage and no basement. I will be insulating and sheet rocking the workspace area in a standard way that one would finish any garage for everyday use. I will construct an iso booth off of the wall used to split the space into two that extends into the storage area. I will be removing the electric garage door opener but keeping the garage tracks and therefore allowing the garage door to be functional manually. Mostly because I want it to easily be switched back to a garage when I leave. I will be plugging up and sheet rocking over the garage window. I will be doing most of the work myself besides having an electrician friend to help with the wire work so it meets code for drywall finish. Budget $1200 preferred and $1800 max.

I was able to save all of the rigid fiberglass treatment and bass traps that I had hanging in my old place as well as the rock wool superchunks.

Problems/Concerns:
1. Finishing off the work area will be merely constructing a two leaf wall. Outside layer-insulation-sheetrock (2 layers of 5/8"). This doesn't provide a whole lot of isolation to the outside world, however I cannot afford (money and space along with having to turn it back to a garage) a room within a room construction, but it will be a step up from what is already standing. I'm here to ask, should I beef up the outside skin with 5/8 rock in-between the studs before applying insulation and then the two layers of rock? How much more iso am I getting by adding not only 2 layers of 5/8" rock on my inside walls, but by also beefing up the outside skin with 5/8 rock in-between the studs? Would any of you suggest skipping either the beef up idea or the second layer of rock because its returns are not worth the costs?

2. The wall I build dividing the garage… Which is better, keeping it a two leaf build with 5/8" on each side, or doubling up the 5/8" on the "studio" side and leaving the other side open (insulation exposed)?

2. Flanking paths: Building the iso booth off of the wall that I'm constructing to split up the garage into two areas leads to flanking pat, isolation loss. This iso booth is for me to house guitar amps, bass amps, singers when doing overdubs and give me some iso away from the amps. I'm willing to not have amps turned to 11 after 10:00 pm. in order to accommodate my neighbors and comply to noise ordinance. Since I'm already cutting corners with my two leaf wall being my ONLY wall, how much am I throwing away by constructing the iso booth off of a flanking wall? If I were to build the iso booth as its own separate entity, that would require me purchasing two sliding glass doors rather than a single door. Iso booth will be "inside out wall" construction with two layers of 5/8 rock on the outside. The iso booth will also be constructed under the garage door rails.

Attached is a sketchup file of my rough idea. I can't get the more detailed sketchup file small enough to post so here are some photos as well.

Garage Conversion rough idea.skp

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photo 1.JPG

Here's what I'm working with regarding the first layer making the outside skin of the building. This is the largest that the gaps get.

photo 3.JPG

[trodden]

Feedback anyone? Re: My ideas and concerns posted above?

[Soundman2020]

Sounds like a pretty bleak situation! But all is not lost: you do have that outbuilding, and it does seem usable. As some people say here: "If that's all you've got, well it sure as hell is better than no place at all!"

I'd like to be able to mix at a useable level, without headphones, after 10:00 P.M.

So levels of around 80 to 90 dBC inside? How quiet do you need that to be outsides (legally))

11' 5.5" X 15' X 8' work space

Decent size. Not huge, but certainly usable for a CR. But how high?

insulating and sheet rocking the workspace area in a standard way that one would finish any garage for everyday use

Well, that limits your options considerably, for isolation! About the only way of doing that is with RSIC clips and hat channel, then a couple of layers of drywall with GG. You should get 40-something dB of isolation out of that (assuming you can seal the outer-leaf well), so your 90 dB inside would down to about 50 dB outside. Is that enough?

therefore allowing the garage door to be functional manually

That won't leave much height to work with. I would consider putting the storage area under the garage door zone, and using the rest of the garage for the CR, so you can use the full available height, up to the joists.

I will be doing most of the work myself besides having an electrician friend to help with the wire work so it meets code for drywall finish. Budget $1200 preferred and $1800 max.

That won't go very far. Your HVAC alone could set you back that much. Sorry, but you are going to need to increase your budget quite a bit to make this feasible.

1. Finishing off the work area will be merely constructing a two leaf wall.

Then you will be limited to typical house isolation levels, around 30 dB or so. That pretty much blows away your dream, of being able to mix on speakers at midnight. You'd need around 50 dB of isolation to accomplish that, which is roughly one hundred times more than you can achieve with a typical coupled two-leaf wall.

I'm here to ask, should I beef up the outside skin with 5/8 rock in-between the studs before applying insulation and then the two layers of rock?

You definitely should yes. Without any doubt. But you don't have the budget to do that, and I'm not convinced it is worth it if you do not decouple the inner-leaf.

How much more iso am I getting by adding not only 2 layers of 5/8" rock on my inside walls, but by also beefing up the outside skin with 5/8 rock in-between the studs?

A fully coupled two-leaf wall is governed mostly by Mass law equations, plus some input from resonance. Assuming mass law alone, two sheets of5/8" drywall will get you about 33 dB of isolation. 4 sheets will get you about 38 dB. Allowing for some resonance help, you might get 40 dB out of that in the mid range, but in the low end of the spectrum you would be getting LESS than 38 dB.

Would any of you suggest skipping either the beef up idea or the second layer of rock because its returns are not worth the costs?

To be very honest, unless you decouple the inner-leaf, then the entire project is probably not worth the cost. You'd get some isolation, yes, but the results would be disappointing, and you'd likely end up mixing on headphones after 10 PM anyway.

2. The wall I build dividing the garage… Which is better, keeping it a two leaf build with 5/8" on each side, or doubling up the 5/8" on the "studio" side and leaving the other side open (insulation exposed)?

Two-leaf. Hands down, no questions asked, absolutely, and without any doubt. 2-leaf MSM construction will ALWAYS get you an order of magnitude increase in isolation, at least, all other factors being equal.

However, that assumes that you do the other walls the same way: if not, then your total isolation will be exactly as good as the WEAKEST wall, whichever one that turns out to be (it might be your ceiling).

Since I'm already cutting corners with my two leaf wall being my ONLY wall,

Fish tank. Think of this a fish tank. Let's say you wanted to build an aquarium to have in your living room, so you can watch the fish swimming around. So you buy a metal frame to make the tank. Then you figure "but I only want to watch them from the front, so I'll only buy one piece of glass for that side of the tank, and I'll do nothing to the other sides". How well do you think that aquarium will hold water? That's about how well your room will hold sound, if you only have one wall that is any good at isolating....

how much am I throwing away by constructing the iso booth off of a flanking wall?

Basically, all of it! If you do not decouple your rooms from each other, you are limited by the flanking and transmission of the ordinary house wall that you are talking about. So your isolation will be in the region of 30 dB here as well. So an amp running at 100 dB, for example, will be very much audible both inside the room and outside the garage, at around 70 dB. That's loud.

If I were to build the iso booth as its own separate entity, that would require me purchasing two sliding glass doors rather than a single door.

Why do you need glass doors on an amp isolation booth? I promise you, the amps really don't care if they can see you or not! You could put a single, very heavy "superdoor" on there, and get reasonable isolation, even for a proper 2-leaf system. Of course, a pair of doors back to back would be even better, but a superdoor can still give you decent isolation.

Iso booth will be "inside out wall" construction with two layers of 5/8 rock on the outside.

Now you are not making sense: you said that you were NOT going to build a "room in a room", but now you are talking about an inside-out wall, which obviously implies that it IS a room-in-a-room build! So I'm confused...

Here's what I'm working with regarding the first layer making the outside skin of the building. This is the largest that the gaps get.

If you are serious about getting good isolation here, you'd need to seal all of those gaps with caulk, then add a layer of 5/8" drywall to beef it up, preferably with Green Glue. If you don't do that and instead just nail drywall to the studs, exactly as is, I'd guess that your total isolation would be in the high 20's.

I can't get the more detailed sketchup file small enough to post so here are some photos as well.

Put it on DropBox, then post the link here.

OK, reality check: If that were my place, and the main goal were to be able to use the room to mix at normal levels any hour of the day or night, this is what I would do:

- Seal and beef up the outer leaf, caulking every single last crack that I could possibly find, then add a layer of 5/8" fire-rated drywall "beef" between every pair of studs, using a full schedule of Green Glue on each one.
- Do the same for whatever is up there as roofing right now, if feasible. If not, then build a "middle-leaf" ceiling up there some place with the same surface density as the outer-leaf wall.
- Build a simple 2 x 4 stud frame to separate the storage area from the CR
- Put two layers of 5/8" fire-rated drywall on only ONE side of that frame, and suitable insulation in the cavity.
- Build a 2 x "X" frame for the inner-leaf ceiling, where "X" depends on the load.
- Put two layers of 5/8" fire-rated drywall on only ONE side of that frame, and suitable insulation above, in the cavity.
- Build a simple 2x4 stud frame for the iso-booth, not connected to any other framing, as a stand-alone unit.
- Put two layers of 5/8" fire-rated drywall on only the OUTSIDE of that frame.
- Put RSIC clips on the stud faces, and hat channel in the clips, on the INSIDE of the iso booth.
- Put two layers of 5/8" fire-rated drywall on the hat channel, with Green Glue in between, and suitable insulation in the cavity.
- Install the electrical system.
- Install the HVAC system, which would be one mini-split for the CR and one mini-split for the iso-booth, plus ventilation for the CR, with suitable silencer boxes, ducts, fans, and registers.
- Build and install the doors for the CR, and the doors for the iso booth.
- Install the DAW temporarily in the CR (using the "standard" layout for such a room), and do an initial REW test.
- Install the typical basic treatment that will be needed, without any doubt.}
- Do another REW test to see how well that worked, and what still needs to be done.
- Design and build suitable treatment to deal with the problems highlighted in the baseline REW test.
- Install major absorption all over the interior of the iso-booth.
- Done!

I'd estimate that I could get upwards of 50 dB isolation out of that, if I did it well. My 90 dB midnight-mix would be down to 40 dB right outside the walls, which probably already meets local regulations, but at 15 feet away it would be below 30 dB, which certainly meets them. (I'm assuming that the wall of my neighbor's house is at least 15 feet away from the studio wall).

So that's how I would do it. Of course, it would cost substantially more than US$ 1800 to do that, but it would meet my design specs.

If I wanted to save money and also make it usable at the end as a garage, my second choice would be to drop the second frame, and replace that with RSIC clips and hat channel for creating the inner decoupled leaf, and I would then have to take a 5 to 10 dB hit on my isolation.

Not sure if that helps!

- Stuart -