Garage studio - questions

Hello, This is my first posting. I've been researching the forum for a few months and found tons of great information, thank you for that. I have a few questions regarding my current project. I'm building a studio in my detached 2 car garage. Live room is 22'x16' w/vaulted ceiling, approx 12' high. Control room is 12'x16' w/8' ceiling and there's a small 7'x7' ISO booth. I'm in the process of framing the building. It sits on a concrete slab. I measured 110db (C weigh) in the live room, playing drums. Approximately 80db outside (12 feet away) and the city noise ordinance levels should be under 55db. I'm looking for a room within a room approach with emphasis in low frequency attenuation. My questions are: As far as the ceiling goes, the current outside leaf is shingles>OSB>frame all exposed in the inside. There's a ridge beam, joists and rafters. My contractor said he could finish the current ceiling by adding insulation and drywall to then install a new ridge beam below the existing one and new rafters that are essentially floating, although they will be attached to the inside wall frame. Then we will add insulation>5/8"drywall>GreenGlue>5/8"drywall - My first thought was this is a 3 leaf ceiling! but I was wondering if it can work. We had a hard time figuring out how to decouple the ceiling without installing new rafters, and this was sort of his interpretation of what a room within a room means... And one other question I had regarding the walls, the current outside walls are: siding>OSB>frame - I'd like to do: siding>OSB>frame>insulation>4"gap>innerframe>insulation>5/8"drywall>GreenGlue>5/8"drywall - Would this provide the best results? Lastly, I can simply have a 2 leaf wall between the control room and the live room, correct? Is there a better approach? Thank you.

anyone? ... :?

felipe411 wrote:

Hello, This is my first posting. I've been researching the forum for a few months and found tons of great information, thank you for that. I have a few questions regarding my current project. I'm building a studio in my detached 2 car garage. Live room is 22'x16' w/vaulted ceiling, approx 12' high. Control room is 12'x16' w/8' ceiling and there's a small 7'x7' ISO booth. I'm in the process of framing the building. It sits on a concrete slab.

How tall is the existing joist framing? The reason I ask is exactly how you plan to get 12 feet of height.

felipe411 wrote:

My questions are: As far as the ceiling goes, the current outside leaf is shingles>OSB>frame all exposed in the inside. There's a ridge beam, joists and rafters. My contractor said he could finish the current ceiling by adding insulation and drywall to then install a new ridge beam below the existing one and new rafters that are essentially floating, although they will be attached to the inside wall frame. Then we will add insulation>5/8"drywall>GreenGlue>5/8"drywall - My first thought was this is a 3 leaf ceiling! but I was wondering if it can work. We had a hard time figuring out how to decouple the ceiling without installing new rafters, and this was sort of his interpretation of what a room within a room means...

Yea, that would produce kind of half of a three leaf...but I am still unclear of what your structure looks like, height wise, and if this procedure you guys are thinking about will be produced in the entire structure.

felipe411 wrote:

And one other question I had regarding the walls, the current outside walls are: siding>OSB>frame - I'd like to do: siding>OSB>frame>insulation>4"gap>innerframe>insulation>5/8"drywall>GreenGlue>5/8"drywall - Would this provide the best results?

Towards a mass/air/mass assembly, yes this is correct. What type and how dense of a siding? If you have OSB as a sheathing and shearing componant then I would think you have a light weight siding. So you would want to mass up the exterior wall cavities at the stud areas in an attempt to reach your isolation goals.

felipe411 wrote:

Lastly, I can simply have a 2 leaf wall between the control room and the live room, correct? Is there a better approach?

You would need to maintain the mass/air/mass fully decoupled assembly procedures to produce and maintain your isolation requirements. The following image shows what is attempted to produce when we try to develop a fully decoupled mass/air/mass environment:

thank you for responding... The current joists sit at about 8', the rafters are about 12' (peak of the vaulted ceiling). I'll be droping the ceiling by 8" if I do it this way. I'm ok if it drops a bit... I'm planning on doing this only in the live room, the control room will be standard 8" tall ceiling. The siding is vinyl, pretty light. I can actually remove all of it and replace it with wood siding. Do you think I should beef up the exterior walls still? With another layer of OSB perhaps? I'm still confused about the control room/live room wall, should this be treated like an exterior wall? Thanks! :D I'll try to post a picture here soon

Here's a picture of the ceiling and the wall I described above. Please note the control room isn't framed yet. The vinyl siding and window will be removed to expose the frame, my question was how to treat this shared wall? There will be an interior leaf in the live room. Thank you.

The vinyl siding and window will be removed to expose the frame, my question was how to treat this shared wall? There will be an interior leaf in the live room.

You seem to have missed the point that Brien was making: you can't just have a "shared wall" between the rooms. Rather, each room must be built independently from the other, fully decoupled, such that you have a proper "room in a room". Like this: The same applies to the ceilings: Each room has it's own independent ceiling that sits on top of the inner-leaf walls for that room, without touching the walls for any other room, nor the outer leaf walls, nor the outer leaf ceiling.

I measured 110db (C weigh) in the live room, playing drums. Approximately 80db outside (12 feet away) and the city noise ordinance levels should be under 55db. I'm looking for a room within a room approach with emphasis in low frequency attenuation.

So you need a total of about 55 to 60 dB of isolation. Right now you have about 30, which is typical of normal house construction. And you need to make it one thousand times better... ! Yup, do the math: each time you increase the isolation by 10 dB, you need to stop 10 times more energy. So increasing from 30 to 40 is ten times, 30 to 50 is one hundred times, and 30 to 60 is one thousand times. This is why the ONLY way you can do that at a reasonable cost, is as outlined above: fully-decoupled 2-leaf MSM isolation.

My contractor said he could finish the current ceiling by adding insulation and drywall to then install a new ridge beam below the existing one and new rafters that are essentially floating, although they will be attached to the inside wall frame. Then we will add insulation>5/8"drywall>GreenGlue>5/8"drywall - My first thought was this is a 3 leaf ceiling!

Right. As Brien said, that would indeed be a 3-leaf ceiling.

but I was wondering if it can work. We had a hard time figuring out how to decouple the ceiling without installing new rafters, and this was sort of his interpretation of what a room within a room means...

Yes it can work. Sometimes there is no choice but to do a 3-leaf, and even though the isolation is lower than for the equivalent 2-leaf, you can compensate for that with more mass and bigger air gaps. In your case, you would do that by putting drywall on the bottom of those joists to create the "middle" leaf, then building your rooms under that, and putting the final ceilings on as a third leaf. If you get enough mass and air gaps, then you can still get the isolation you want.

Lastly, I can simply have a 2 leaf wall between the control room and the live room, correct? Is there a better approach?

Yep! Do each room as a single leaf, within the outer shell of the building, which is your outer leaf. That gives you the correct "fully-decoupled 2-leaf room-in-a-room" that you need for maximum isolation. The same applies to all doors and windows: they must also be done double, with a pair of back-to-back doors, and a pair of back-to-back glass panes. - Stuart -

Thanks guys! I now have a better understanding and feel pretty good about the build... I'll try to keep this updated with pictures and questions as I go along, thanks for the help!

Hey guys, just wondering if you can take a look at this layout and maybe give me some thoughts? I'm keeping things simple and functional, 2 rooms with an entrance. The rectangle on the left side of the control room represents the garage door, which will be completely removed. The one in the control room represents the glass. The red wall is the "shared" wall which we discussed above. Also, I can't seem to find density details for R13 insulation :shock: I looked at manufacturers websites and such... does anyone know? R13 seems more cost effective than mineral wool, for the walls and ceiling. Thanks!

thoughts? :D

anyone?

The control room exterior walls are up (the little garage window will be removed and the studio glass placed next to it on the opposite side of the door). Not the best weather for this type of work right now :? Anyone care to provide some input regarding the questions above? Also, regarding insulation, I found some posts stating density at 50kg/m3 for mineral wool as preferred/recommended... I was thinking about insulating the wall cavities with this: http://www.atsacoustics.com/item--Roxul ... -1006.html And standard R13-R15 for the ceilings ??? Thanks!

Control room ridge beam is up.

just wondering if you can take a look at this layout and maybe give me some thoughts?

There's not much to go on there! Just a couple of rectangles inside another rectangle... You'll have to provide a lot more detail for anyone to be able to offer useful comments. I'd suggest that you do the design in SketchUp, showing all the details, and post that here. That's probably why nobody commented: there's nothing to comment on! :)

I was thinking about insulating the wall cavities with this:

That would work fine, but you'll need more than 2". See if you can find 4" stuff, and use one of those for the outer leaf, and another for the inner leaf. Same for the ceiling. - Stuart -

There's not much to go on there! Just a couple of rectangles inside another rectangle... You'll have to provide a lot more detail for anyone to be able to offer useful comments. I'd suggest that you do the design in SketchUp, showing all the details, and post that here. That's probably why nobody commented: there's nothing to comment on! :)

Right, I just realized how basic it was :? . I'll download Sketchup today and put something together. I received a message from John with some suggestions as well, thank you all.

That would work fine, but you'll need more than 2". See if you can find 4" stuff, and use one of those for the outer leaf, and another for the inner leaf.

I can do 2 bats of 2" each for a total of 4", that should do it. Thanks!

Hello, I downloaded Sketchup last night and was able to put this together hoping to get some input. As you can tell, I'm not very good at it but I think this can give you a good idea of what I'm trying to do. Please note, in the live room, the slat resonators are supposed to be angled, I just couldn't figure out how to do it in Sketchup. I'm going for general broadband absorption and diffusion, not targeting any specific frequency. In the control room, I'm shooting for panels and bass traps in the corners. The black grid looking thing in the back wall is where the guitar amps are going to be. Let me know what you think, thanks! Also, regarding the mineral wool insulation, I priced it out and turns out to be really expensive for 2 sets of 2" to achieve 4" thickness. I can get 3" bats and cut the cost by 30%. Will it be ok to do 3" bats for the outer leaf and inner leaf? Thank you.

Hello! yesterday we removed the garage door and framed the last wall in the live room, the control room roof is framed and the live room floor is framed as well... next is all the interior framing, studio glass opening and electrical. We learned that removing the garage door should be done carefully as the spring holds a lot of tension and it could snap... I'm glad we checked youtube before we started!

the live room floor is framed as well

:shock: :!: :?: Floor? What floor? You already have a perfectly good concrete slab on grade down there, so why would you want to wreck the acoustics and isolation by framing a thin wooden floor above that??? Are you aware of how badly that will damage both your isolation and your acoustics? - Stuart -

The reason why the floor had to be framed in the live room is because it was slanted pretty badly (to prevent flooding), also the new concrete slab (control room) which is detached from the live room sat at a higher level. In order to level both rooms and install hardwood the floor in the live room was framed and insulated. It will connect to the inner frame in the live room completely detached from the outer frame.

That's the classic way to NOT float a floor. You probably haven't read this thread (below), but now would be a very good time to do that. http://www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=8173 - Stuart -

felipe411 wrote:

The reason why the floor had to be framed in the live room is because it was slanted pretty badly (to prevent flooding), also the new concrete slab (control room) which is detached from the live room sat at a higher level. In order to level both rooms and install hardwood the floor in the live room was framed and insulated. It will connect to the inner frame in the live room completely detached from the outer frame.

That's the classic way to NOT float a floor. You probably haven't read this thread (below), but now would be a very good time to do that. http://www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=8173 - Stuart -

I actually did quite a bit of research about this. My intention was not to float the floor as it didn't seem necessary. The floor built was standard, I just made sure the frame wasn't connected to any of the outer leaf walls. I suppose you can call it a "floating floor" as it sits on a frame but that wasn't my goal though. It was done that way for structural reasons, placing hardwood floors on a slanted surface wasn't an option and I didn't want my drums to roll away! I appreciate the feedback.

I actually did quite a bit of research about this.

Here on the forum? There are many threads about the problems with floated floors, they types of issue they cause, and the ways of avoiding that.

My intention was not to float the floor as it didn't seem necessary. The floor built was standard, I just made sure the frame wasn't connected to any of the outer leaf walls.

All that means is that it is decoupled from the outer leaf, which is good to a certain extent, but still does not prevent the acoustic issues.

It was done that way for structural reasons, placing hardwood floors on a slanted surface wasn't an option and I didn't want my drums to roll away!

There are other ways of leveling floors...

I suppose you can call it a "floating floor" as it sits on a frame but that wasn't my goal though.

Right, but that's what it is. Even though you didn't intend it to be one, it still is one. It is basically a very large drum: a flexible membrane stretched over a rigid frame, enclosing a resonant cavity. Like all drums, it will resonate at certain specific frequencies, and those could be excited either by impact or by sympathetic resonance. The frequencies that it is tuned to depend on three factors: the mass of the floor (or rather, the surface density), the depth of the air gap (which varies in your case, as the underlying slab slopes, implying broad resonance at many frequencies), and the resilience of the spring in between (the air in the cavity, in your case). Basic MSM theory applies, the same as for the walls and ceiling. Basically, your floor will resonate at some frequencies but not others, which is what floating floors are supposed to do, but for a properly floated floor the mass, depth and resilience are carefully chosen such that the fundamental resonant frequency is an octave lower than the the lowest frequency that needs isolating. That needs a lot of mass, as the above thread points out. That type of mass can only really be obtained from materials like concrete. Wood isn't massive enough to do that, so the resonant frequency will be very high, within the audible range. How much of a problem that will be, remains to be seen, but there will undoubtedly be resonance going on. That wasn't shown in your PDF or SKP files. That's one of the reasons why we suggest doing a complete model in SketchUp before people start building, so we can spot potential catastrophes in the design stage, where they are easy to fix, rather than in the "Oops! But I already build it! What now?" stage, where they are much harder (and more expensive) to fix. - Stuart -

I understand, do you have suggestions to alleviate the issue?

Remove the framed floor.

xSpace wrote:

Remove the framed floor.

Ok, will do.

Hey guys, I'm trying to figure out the HVAC. I have a mini split system I'll be using. My HVAC guy said he could run the copper pipe through the ceiling (between the inner/outer frames) across the room to then connect it to the outside unit. Will this be ok? I'm trying to resolve the ventilation issue. I've been reviewing the various silencer box designs. The question I have is how to calculate the size? Is there a formula? Or can anyone point me in the right direction? Once the box is built and installed, do I need a fan to push the air into the room? And lastly, if I'm mounting this box on a wall, should it be attached to the outside frame? or inside frame? The glass opening is done! Thanks!

Doing some siding today...