Large Second Floor Garage Studio Project

[cgardnerma]

Hello there!

First a little about myself. I played in a band for years and have been a studio hobbyist for 25 years. I am not a working pro, but have made records in my old studio which I built from scratch in an existing carriage house. My previous build in the 00's, with the help of Rod's book and I think an early version of this group (??), was a full control room and live room within a room in an existing residential structure. For 10 years, we rehearsed and tracked in it with great success. I have read Rod's book cover to cover twice. I was a contractor for 10 years.

I am in the planning stages (downpayment paid, waiting for first draft plans) for building a new 28 x 36 three-car garage on my one acre lot which will house my studio on the second floor. (Yes, I understand the limitations this creates.) This will replace a 24x24 "barn" that I have been using as my studio for about a year. The current structure is 2x4 construction with fiberglass insulation. The walls are single layer drywall and the cathedral ceiling is loosely fitted, rough pine boards with 1/4" gaps that does little more than hold the insulation in place! It also has cheap thermal windows facing neighbors property. Needless to say I don't have much isolation today, but between good neighbor/wife relations and keeping any loud drum/bass tracking in daytime hours, I have been able to limp by. Now it is time to tear it down and build a new home for our cars and my studio.

Here's some detail on the new project including isolation goals, property, and the new structure:

Budget:
- I am assuming a minimum of another $75K on top of the basic structure, but don't want to chase a few extra dB at huge expense.
- My decision to be upstairs and include windows limits the amount of achievable isolation, so I could use advice on avoiding expenses that would be negated by the second floor location or other core issues in my plans.

Isolation Goals:
- 90% of usage is quiet overdubbing and rough mixes, 10% of time I track live drums. Kids have been taking drum lessons. (~115db measured)
- Old building is only giving me 25-30dB (C-weighted/fast) at exterior wall.
- Only concern is wife/neighbors outside the structure. I can work around noises outside. I have been making it work with this, so I don't need miracles. But it is too loud and would bother me if I were a neighbor.
- Noise going to the 1st floor garage portion is not an issue beyond what needs to happen to keep noise contained within overall structure.
- Understand second floor location of my new room is problematic, but that is a settled part of plan. Given that, I would like to "max out" isolation up to that limitation.
- I'm hoping I can get to an honest 40-45dB TL which I think that when combined with with my "no drums after 10pm rule", gets me there. Obviously more is better.

Property:
- Neighbors will be behind new structure and to one side of new structure. About 75ft from exterior walls to their walls.
- My house is about 30 ft from gable end of new structure.
- Structure will be 15ft from property line at minimum. Perhaps 10 ft farther in final plan.
- Town only restricts "excessive noise" as far as I can tell, so keeping the neighbors happy is really the goal.

New Structure:
- 28 x 36 wood frame garage. (see attached pictures of very similar structure)
- 2 x 6 walls, trussed roof/ceiling, engineered joist 2nd floor.
- Second floor single room studio. Floor has 28ft clear span on engineered joists. (Big old drum head!)
- There WILL be windows. Given 90% of time in studio is quiet work, I am not willing sacrifice natural light. I will spend money here as needed or build window plugs for louder situations.
- Stairway to downstairs garage which I will build out for isolation as needed.

Current thinking:
- I am waiting for FIRST DRAFT plans so I have time to change just about anything.
- I have deleted any windows and doors facing neighboring properties
- I have spec'd laminated glass inserts in Anderson windows. This get to a claimed STC34. I know this doesn't get me there and I understand STC doesn't mean anything for the low end which will be my problem. Have questions below on this.
- Have spec'd double 1/2" plywood sheathing on walls to add mass
- Have upgrade roof sheathing to from 1/2 to 3/4" to add mass
- Have spec'd double 3/4 for floor to add mass
- I am assuming double 5/8 drywall with green glue. Willing to go to clips and hat if the floor/window situation can keep up. Would like to avoid room within room given cost/timeline and my more modest isolation goals, but not out of the question. More questions below on that.
- Insulation will likely be flash and batt with 1-2" of spray foam and the rest fiberglass. Foam is for air sealing, fiberglass for damping. I know I am making a tradeoff with the spray foam, but seam caulking this entire structure is not practical. Also dealing with very strict local code on insulation.
- Heat/AC will be mini split with supplemental resistive baseboard or panel for super cold spells
- I am shopping for a HRV which will include baffles as needed

Some current open questions:

1. Given the second floor location, joist construction, and obvious flanking path to outside, what is my best case isolation scenario? Am I right in thinking that I should base how far I go on other isolation paths on this "max" possible outcome?

2. I know my insistence on windows is my other limiting factor, but here it seems like I can spend money to get to 40-45dB if necessary. My current thinking is laminated Andersen windows only facing away from neighbors. If needed on actual testing, I am willing to retrofit neoprene gasketed, 1/2" laminated inserts in each of the windows. I know this would make a triple leaf with Andersens, but I won't pass inspection without a thermal window to start. Thoughts?

3. I know low end noise is largely omni-directional, so is it silly for me to delete doors/windows facing the neighbors? Do I gain anything here? Part of me hopes that the laminated windows only facing away from neighbors could be enough...

4. Any thoughts on my external leaf layering? Not sure I can do more there.

5. The roof truss structure is an interesting challenge. Given what you see in pictures, do I still treat this as a two-leaf system and simply cram as much fiberglass in there as I can? It's a big air space, obviously.

6. Any thought on how to treat the inner floor leaf? I spec'd double 3/4" T&G plywood for now just to add mass, but I'm pretty lost here given the flanking path to outside. I don't have live load/dead load specs for the floor yet, but I am definitely not going to spec steel beams and pour a slab!

7. On the outer floor leaf (facing down to garage), what should I do here? Fiberglass and double drywall? Clips and hat? Because this is a big empty garage below, I am unsure how to treat this.

8. Similar to above, I am unsure how to treat the ground floor garage area in general. I am willing to do what is needed here, but the garage doors and windows are obviously weak spots. I will likely insulate and drywall at a minimum. Am I OK focusing on isolating the upper room and leaving it at that?

9. Finally, I know I mentioned I wanted to avoid room within a room. My thinking is that I can do less given my relatively modest isolation requirements. I was also assuming the second floor location and subsequent flanking paths would sacrifice much of the benefit of room within a room. Am I wrong? I could reconsider here.

Pictures of new structure (nearly identical to what I am building):

Garage_Outside.jpg

Garage_Inside.jpg

Thanks so much for listening. I'm grateful for any feedback/guidance/mockery you all can share.

Chris

[Gregwor]

1. Given the second floor location, joist construction, and obvious flanking path to outside, what is my best case isolation scenario? Am I right in thinking that I should base how far I go on other isolation paths on this "max" possible outcome?

You're probably governed by mass law here.

2. I know my insistence on windows is my other limiting factor, but here it seems like I can spend money to get to 40-45dB if necessary. My current thinking is laminated Andersen windows only facing away from neighbors. If needed on actual testing, I am willing to retrofit neoprene gasketed, 1/2" laminated inserts in each of the windows. I know this would make a triple leaf with Andersens, but I won't pass inspection without a thermal window to start. Thoughts?

You need to find their full frequency isolation values. Mass is everything here.

3. I know low end noise is largely omni-directional, so is it silly for me to delete doors/windows facing the neighbors? Do I gain anything here? Part of me hopes that the laminated windows only facing away from neighbors could be enough...

It's not silly. If there is going to be a part that "leaks" it's going to doors or windows.

4. Any thoughts on my external leaf layering? Not sure I can do more there.

Since you're relying on mass law here, I would use 2 layers of 3/4" with Green Glue.

5. The roof truss structure is an interesting challenge. Given what you see in pictures, do I still treat this as a two-leaf system and simply cram as much fiberglass in there as I can? It's a big air space, obviously.

What style of roof is it (I mean, what ventilation method)?

6. Any thought on how to treat the inner floor leaf? I spec'd double 3/4" T&G plywood for now just to add mass, but I'm pretty lost here given the flanking path to outside. I don't have live load/dead load specs for the floor yet, but I am definitely not going to spec steel beams and pour a slab!

Make sure your joists/structure can handle any weight you might throw at it! I would also Green Glue this.

7. On the outer floor leaf (facing down to garage), what should I do here? Fiberglass and double drywall? Clips and hat? Because this is a big empty garage below, I am unsure how to treat this.

Even if you clip and hat the ceiling sheathing, you're still flanking at the walls so I see that as a waste of money (clips and hat are expensive). Plus, since it's a garage, you will probably want things hanging off of it (such as garage door rails) so your isolation will be trashed from that stuff since you can't hang heavy things off of your clips and hat.

8. Similar to above, I am unsure how to treat the ground floor garage area in general. I am willing to do what is needed here, but the garage doors and windows are obviously weak spots. I will likely insulate and drywall at a minimum. Am I OK focusing on isolating the upper room and leaving it at that?

Concentrate on isolating the room where your noise is coming from --- your recording room.

9. Finally, I know I mentioned I wanted to avoid room within a room. My thinking is that I can do less given my relatively modest isolation requirements. I was also assuming the second floor location and subsequent flanking paths would sacrifice much of the benefit of room within a room. Am I wrong? I could reconsider here.

Your price will go up drastically if you want a room a room for obvious reasons and the fact that your structure would have to be extremely beefed up in order to hold the extra weight.

Greg

[cgardnerma]

>>Greg, thank you so much. This is very helpful. Comments and follow on questions below.

1. Given the second floor location, joist construction, and obvious flanking path to outside, what is my best case isolation scenario? Am I right in thinking that I should base how far I go on other isolation paths on this "max" possible outcome?

You're probably governed by mass law here.

>>Yes, for sure. It seems the biggest question is given the floor flanking to outside structure, what's a reasonable expectation of max TL to the outside? Is 40dB in the realm of possibility? Without an existing structure to test, it's guesswork, I know. But this figure helps drive where to invest and where not to.

>>Related question: Does hat and clip in upstairs studio room make sense given the floor with flanking straight outside? If it gets me 4-5dB and better low end control I might do it, but if the floor will be just drumming out to the walls, perhaps not. There doesn't seem to be any easy math to calculate how a floor resonating/flanking translates into the real world.

2. I know my insistence on windows is my other limiting factor, but here it seems like I can spend money to get to 40-45dB if necessary. My current thinking is laminated Andersen windows only facing away from neighbors. If needed on actual testing, I am willing to retrofit neoprene gasketed, 1/2" laminated inserts in each of the windows. I know this would make a triple leaf with Andersens, but I won't pass inspection without a thermal window to start. Thoughts?

You need to find their full frequency isolation values. Mass is everything here.

>>Still looking here. I have my builder working with Andersen on more detailed specs.

3. I know low end noise is largely omni-directional, so is it silly for me to delete doors/windows facing the neighbors? Do I gain anything here? Part of me hopes that the laminated windows only facing away from neighbors could be enough...

It's not silly. If there is going to be a part that "leaks" it's going to doors or windows.

4. Any thoughts on my external leaf layering? Not sure I can do more there.

Since you're relying on mass law here, I would use 2 layers of 3/4" with Green Glue.

5. The roof truss structure is an interesting challenge. Given what you see in pictures, do I still treat this as a two-leaf system and simply cram as much fiberglass in there as I can? It's a big air space, obviously.

What style of roof is it (I mean, what ventilation method)?

>>It will be non-vented since I am doing 2" of foam and then fiberglass to R49 or so.

6. Any thought on how to treat the inner floor leaf? I spec'd double 3/4" T&G plywood for now just to add mass, but I'm pretty lost here given the flanking path to outside. I don't have live load/dead load specs for the floor yet, but I am definitely not going to spec steel beams and pour a slab!

Make sure your joists/structure can handle any weight you might throw at it! I would also Green Glue this.

>>I confirmed a 10 psf dead load and 40 psf live load for structure. It can handle double 3/4" with a 10psf dead load rating. Good thought on green glue.

>>Second question: The plan is for double floor installed PRIOR to the framing for second story walls. This obviously continues the flanking issue since wall plate will go on top of double floor. I could install the second layer AFTER the walls go up, but that may be more trouble than its worth for minimal gains. Thoughts?

7. On the outer floor leaf (facing down to garage), what should I do here? Fiberglass and double drywall? Clips and hat? Because this is a big empty garage below, I am unsure how to treat this.

Even if you clip and hat the ceiling sheathing, you're still flanking at the walls so I see that as a waste of money (clips and hat are expensive). Plus, since it's a garage, you will probably want things hanging off of it (such as garage door rails) so your isolation will be trashed from that stuff since you can't hang heavy things off of your clips and hat.

>>OK, this is very helpful. Big head slap on mounting things to ceiling! I will indeed insulate and double drywall for isolating the upstairs, but skip the clips.

8. Similar to above, I am unsure how to treat the ground floor garage area in general. I am willing to do what is needed here, but the garage doors and windows are obviously weak spots. I will likely insulate and drywall at a minimum. Am I OK focusing on isolating the upper room and leaving it at that?

Concentrate on isolating the room where your noise is coming from --- your recording room.

>>Perfect.

9. Finally, I know I mentioned I wanted to avoid room within a room. My thinking is that I can do less given my relatively modest isolation requirements. I was also assuming the second floor location and subsequent flanking paths would sacrifice much of the benefit of room within a room. Am I wrong? I could reconsider here.

Your price will go up drastically if you want a room a room for obvious reasons and the fact that your structure would have to be extremely beefed up in order to hold the extra weight.

>>Right. Wasn't even thinking about dead load, but of course you are right.

Greg

[Gregwor]

Comments and follow on questions below.

To make it easier to read in the future, just copy whatever sentence or paragraph you want to reply to, then put the quote button and paste the text. Reply below each one

what's a reasonable expectation of max TL to the outside? Is 40dB in the realm of possibility? Without an existing structure to test, it's guesswork, I know. But this figure helps drive where to invest and where not to.

Mass law says that in a perfectly sealed and constructed build, 2 layers of 5/8" drywall will give you 32.93 dB of isolation. That is the broadband frequency isolation, not at a specific frequency of course.

>>Related question: Does hat and clip in upstairs studio room make sense given the floor with flanking straight outside? If it gets me 4-5dB and better low end control I might do it, but if the floor will be just drumming out to the walls, perhaps not. There doesn't seem to be any easy math to calculate how a floor resonating/flanking translates into the real world.

Exactly, your floor is going to be the weak link if you clip + hat the rest of the room. You could "float" the floor using Glenn's drum riser design style. That would help but you would lose some room height doing that. That would be your best bet probably.

>>It will be non-vented since I am doing 2" of foam and then fiberglass to R49 or so.

They yes, treat it as a 2 leaf system. Seal everything, stuff the cavity with insulation.

>>I confirmed a 10 psf dead load and 40 psf live load for structure. It can handle double 3/4" with a 10psf dead load rating. Good thought on green glue.

Okay so make sure that you're good to go if you were to throw down insulation and another 2 layers of 3/4" plus all of your gear, furniture and people up there.

>>Second question: The plan is for double floor installed PRIOR to the framing for second story walls. This obviously continues the flanking issue since wall plate will go on top of double floor. I could install the second layer AFTER the walls go up, but that may be more trouble than its worth for minimal gains. Thoughts?

The order won't matter. Do whatever is faster and ultimately cheaper to build. Again, I think your flooring issue can be resolved or at least improved by floating subfloor on insulation.

Greg

[Elusive Sounds]

Hi Chris,

Interesting read here. Looks like you will end up with a very nice garage studio combo. I'm dealing with a lot of the same questions as I am researching isolating my little studio room that sits on top of an attached garage.

As for your external windows, if you have a local manufacturer that can build you custom window units, take a look at the PDF here. It will give you an idea of what you can expect for TL based on the STC and OITC specs:

STC VIRACON.pdf

It is not 100% clear to me how effective these methods are against airborne sound, but for your floor situation, have you considered a decoupled (not floated) solution such as what is outlined by Rod Gervais in figures 10.16 and 10.19?

10.16.png

10.19.png

Another example of these techniques are shown in Glenn's Drum Riser design:

GLENN-example drum riser 2.jpg

These are some of the methods I am looking into for my studio, with the addition of generous amounts of green glue between all solid layers.

Please keep us posted of your progress and design decision.

Thanks,
Marc

[cgardnerma]

Hi Chris,

Interesting read here. Looks like you will end up with a very nice garage studio combo. I'm dealing with a lot of the same questions as I am researching isolating my little studio room that sits on top of an attached garage.

As for your external windows, if you have a local manufacturer that can build you custom window units, take a look at the PDF here. It will give you an idea of what you can expect for TL based on the STC and OITC specs:

STC VIRACON.pdf

It is not 100% clear to me how effective these methods are against airborne sound, but for your floor situation, have you considered a decoupled (not floated) solution such as what is outlined by Rod Gervais in figures 10.16 and 10.19?

10.16.png

10.19.png

Another example of these techniques are shown in Glenn's Drum Riser design:

GLENN-example drum riser 2.jpg

These are some of the methods I am looking into for my studio, with the addition of generous amounts of green glue between all solid layers.

Please keep us posted of your progress and design decision.

Thanks,
Marc

Will do, Marc. As you can imagine, the process is a little clogged up at the moment with all the business shutdowns, but we're still moving forward. I was able to switch my floor deck to a truss system which will hold more load so I can up the mass on the floor. Still, since I am not on a slab, I am not expecting miracles, due to flanking paths. The plan will end up being doubled up exterior sheathing, doubled up 3/4 on floor, double drywall and green glue, double windows and good neighbor relations!

cg