New Design - moved from Studio Construction

I moved this from the studio construction forum over here. It will primarily be my diary, and if others see something really dumb that I am doing, they can offer what they have. Hopefully it will help others as they design as well. _______________________ Hey all - I am starting plans for a garage/studio/apartment design. Unfortunately for me, the studio will be the last part that gets built (probably years down the road), but one of the critical aspects of the initial design. The plan is to be able to record full bands (typically rock/pop), purely for personal use (I don't plan on being for hire), on the main floor. I only have the shell drawn up now, because, simply, that's what I'm starting to plan for now. The general size will be a 30'x44' building. The front 30'x24' will be a garage, the back 30'x20' will be the studio. I will then be building a second floor over the garage area, as a small apartment. The garage and little apartment will be the first priority to be finished. As far as surrounding area, I live on a two acre plot, with corn fields totally surrounding me, a (local) state highway east of me by approximately 500 feet, the nearest friendly neighbor is 250 feet away, the nearest one that doesn't appreciate music is 0.5 miles away, the closest truly busy freeway is 1.5 miles away. The biggest outside concern would be a random heavy truck on the state highway, or tractors plowing the field. Actual decibel levels for these, I don't have. Budget: Well, honestly, I don't know. The initial construction of the building I expect will be in the $20,000 range, with finishing the "apartment" to be that again - as I plan on doing all the work myself (with the exception of the concrete work for the foundation). The studio itself I understand will be thousands more, so I will deal with that when I can afford to. I just want to make sure the preliminary work is done properly while I have the chance, so I don't have to fight a bad mistake later. I don't have it drawn in yet, but the door to the studio will be from the garage. At least, that's the plan now. I plan on no windows in the studio to the outside, and HVAC I am still deciding on. I could use electric heat, based off from a separate service to this building. Since I live in Michigan, air conditioning is nice, but not absolutely necessary. However, I am also considering an HVAC system for the apartment, and may be able to leach from that system. Again, I am VERY early in the design. For electricity, I have a 400 amp single-phase service for my property. 200 amps currently go to the house, leaving 200 amps available to this building. I plan on placing two 100 amp panels in this building - one for the apartment/garage, one for the studio. If I do decide to heat with electric baseboard heat, I can work from the 100 amp panel for the garage/apartment. My questions are here, and I will update as the design updates.: (1) Since the studio area will be similar to an addition to the back of the garage, I planned on placing two layers of half-inch sheets of drywall on the garage side for the outer leaf there. I did not do the same for that wall of the apartment, I didn't think it was necessary. Am I correct? Then two layers of half-inch OSB around the studio section alone (outside of the building). The studs for the studio will then, necessarily, be 1/2 inch inboard compared to the studs for the garage. Does this make sense? - Answer: With the design changed to a scissor truss, I can place two layers of drywall in the area intersecting with the apartment wall, and not worry about the resonant frequency as it will be below the frequency range applicable to sound isolation (2) If I use two layers of half inch drywall on the ceiling of the primary studio, will this be sufficient to block sound to the garage/apartment? I know that, at this point, I would then have the headers and studs exposed on the studio side of the walls, but I wanted to be able to leave room for either inside-out walls, or to give more space for the air gap between leaves. The last thing that I want to do is place boards on the inside and outside of these studded walls, as that would create a three leaf system. Answer: Answered above I am attempting to attach the sketchup file, but it's currently 1MB - and I am getting a max file size error of 500kB. What am I doing wrong? answered - I had to clean it up and zip the file More questions coming later, I'm sure. New questions up: (3) When I pour my floor (inside the foundation), is it an idea to pour separate isolated slabs for each of the "room-in-room" rooms? Answer thus far: By the looks of it, others are starting to ask similar questions. It looks like the answer is that the structure would be compromised too much, and I should simply pour one floor. (4) Since I've gone with scissor trusses for the ceiling/roof of the shell, It has created a concern with my control room. In order to increase room volume further away from the speakers, I have to turn the room around - which means my back would be facing the live room - losing visual communication. Which is more important? If I have forgotten anything, please let me know. I have attempted to be as thorough as possible.

welcome bob - in sketchup go to window, model info, statistics and click purge unused. Every component you pull into sketchup is stored, when you purge everything it removes the ones you are using in the model. The board is currently set to accept attachments up to 800kb.

Thanks John. That didn't do it, but I just zipped the file, and it dropped to 150kB. Hopefully that'll work. The file is attached, and I have NONE of the studio designed yet in it - just the building and the framing of the apartment. My primary concern right now is the connection between the studio area and garage/apartment. I do have a basic design that I drew up in Solidworks, and am adding it as picture. The doors are not shown yet, but the plan is going from the garage to the control room, through the control room to the iso booth, and through the iso booth to the live room. I understand that I will require a beam somewhere across the span of the ceiling line of the studio, but I don't have a place for it yet. Once I get a good solid studio design in place, I will be able to place the beam. Also, please ignore that I don't have a rail on the steps going up to the apartment in the sketchup file - I just haven't gotten that drawn in yet.

Bob - if you replaced your trusses with scissor trusses over the live room you'd get more ceiling height and an angled ceiling.

I'll need to check to see if scissor trusses will span 30 feet with snow load. It would definitely give more space. I've set the current ceiling height at 9 feet to give me that extra space, but I assumed that the beam would be necessary due to the span - and that would take away from that space.

Hi Bob.

bwilkinson wrote:

"Since I live in Michigan, air conditioning is nice, but not absolutely necessary. However, I am also considering an HVAC system for the apartment, and may be able to leach from that system."

Actually that may not be as easy as you think. When heat and air systems are installed they are designed for specific room/volume so having a heat and air that the installers designed for one place and then attempting to pull from it into another part of the building, effectively cutting the systems ability in half +/- will create problems in both parts of the building. Moisture extraction comes to mind as does return air. I have a small room but when equipment is turned on, amps, black boxes, computer(s), guitar amps, keyboards, overhead lighting et. al., it gets hot, any time of the year. It's Spring here @ Xit4 and my room is warm even now ;) Think about that HVAC as it is often one of the biggest oversights and can prove to be one of the bigger room to room, machine to room, air-borne leaks you may encounter.

bwilkinson wrote:

"(2) If I use two layers of half inch drywall on the ceiling of the primary studio, will this be sufficient to block sound to the garage/apartment? "

Depends on several things. The air gap makes a difference on how low the frequencies go that the assembly can isolate but this area(ceiling) has to looked at just as if it is a wall assembly. The best results will be from decoupling the ceiling of the studio from the rest of the structure. If this is what you are already inclined to do, then let me move forward. When you take into account the levels of sound that this room will be subject to this determination will allow you to better understand if this idea of 2 - 1/2 inch sheets of rock will do what you need. Based on the dimensions you mentioned above, you are going to use wood I-beams or floor trusses to make this span? You have several options with a new build, weight restrictions permitting. You can add the mass directly to the top of the floor trusses which is the easiest of any solution...bar none. The alternative is that you will cut out strips of whatever you use for mass and install in-between the ceiling joists. Which will prove to be both time consuming, frustrating and tedious...trust me ;) If you are not thinking about using floor trusses or wood I-beams to make that span, reconsider. If you place a pole(s) it will complicate the build. It can be done, but there again, easy is what you are going to want after about three months into the studio build, whenever that date finally comes for you.

bwilkinson wrote:

I'll need to check to see if scissor trusses will span 30 feet with snow load.

Check out Marc's build in Canada where snow load is pretty serious :) viewtopic.php?f=2&t=8985&start=30

X - HVAC: I think I misspoke myself when I said I would leach from the apartment. That's typical of me expecting that everyone else knows what I am thinking when I state it. What I meant to state was that I could have the HVAC system designed, when it is installed in the apartment, to be designed for both the apartment and the studio - rather than installing two different systems. Ceiling: My plan is to put in 9 foot ceilings in the building, then building my individual rooms with a totally separated ceiling, most likely in the 8 to 8 1/2 foot range. So, the ceiling in the building would actually act as my outer leaf, and I would have a second set of "ceiling joists" mounted on top of my inner leaf walls, creating my inner leaf. In addition, with John's advice about the scissor trusses, I can get even more room! Now, however, I really need to take a look at how the "inner rooms" will lay out with the building, and how I can make that work. I don't think I was perfectly clear on my discussion of where the apartment will sit - I've updated this from when it was in the construction forum. The garage will be 30'x24'. The apartment will be 30'x24' - the second floor of the garage. The studio will be 30'x20', attached to the north wall of the garage/apartment. John - Seeing that makes perfect sense! Simply placing a truss widthwise across the room at the peak, and tying the pitched trusses directly into that gives me two advantages - (1) it gives me the raised ceiling, and (2) eliminates the need to place a beam below, taking up precious room. I may even be able to do something similar in the garage area for the apartment floor joists, in which I can place a beam in the center of the building, and tie the joists into the side with joist hangers - assuming that the strengths work out. One thing I do consider, though, is that by using scissor trusses, I will have part of the studio airspace directly connected to the apartment - whereas the current design, building a flat ceiling, will have the ceiling of the studio airspace at the same level as the ceiling of the garage - therefore the apartment would not be directly "coupled" by air to the studio.

Okay, I'm stuck with the outer leaf mass issue. Attached, you will see the intersection of the wall where the studio will attached to the rest of the building. I have oversimplified it to show the problem. My current plan is to place two sheets of gypsum board on the garage side of the first floor wall, and nothing on the studio side of the wall. The inner leaf mass will be, obviously, attached to the framing of each individual room. This would give me the greatest air gap between leaves. However, the apartment (second floor) is where I get into trouble. If you see in the picture, the ceiling of the studio, using scissor trusses, would now encroach on the apartment studs. This will then mean that I would either have to place two sheets of gypsum on that wall inside the apartment, as well as two sheets of OSB on that outside wall (above the roof trusses), or I would have to place two sheets of gypsum on the studio side of that wall, creating a three leaf system. This problem didn't occur when I used a flat ceiling, because my ceiling was below this area. I was able to avoid the problem. Is there an easy way out of this? Will it be simpler for me to go back to a flat ceiling, and accept the lost height to avoid the can of worms I'm opening?

I don't see a problem - just make sure they don't connect to each other.

I don't understand what you mean, John. The roof truss will have to connect to the wall - that is the end wall of the studio shell.

Then I guess I'm not understanding your description and picture. Maybe if you could post your SkecthUp model here, it would be easier to understand what the issue is. - Stuart -

Bob - there are two trusses in the design I pointed you to. One is the main building truss which is lined underneath creating the outer leaf. The other is the inner truss creating the inner leaf. the outer leaf truss will connect to your apartment wall, the inner one will attach to your room within room wall. here's the outer trusses on place connected to the trusses over the control room which in your structure would be your apartment wall. The lower trusses are then added inside and they sit on the studio walls as shown in this picture.

I now understand the confusion. Please understand, I am only discussing the outer leaf truss. It attaches to the framing of the rest of the building. So far, we are together. Here's where we diverge: I need a SEALED outer leaf. To seal it, I wanted the 1" of gypsum on the garage side of the wall, and studs exposed in the studio. Again, I'm only discussing outer leaf. Now, in the apartment, (second floor) I have gypsum in the apartment. On the studio side of the studs, I have a truss attached. Above the truss (on the wall), I have OSB and siding. Below the ceiling side of the truss (on the wall), I have air. I can put my hand between the studs, and touch the gypsum in the apartment. I can reach between the truss and the gypsum upward, inside the apartment wall. This is not a good sealed outer leaf. If I cover this up with 1" of gypsum (on the studio side of the studs), I now have two leaves between the studio and apartment, and have not even started building my actual inner leaf yet. Please do not take this as me being sarcastic at all, I'm trying to explain this "big bird style" because I am not doing well at explaining it thus far.

If what you are refering to is the "concern area" in the drawing, do not worry about triple leaf. The space above the ceiling line is so large that the resonance point is way below any frequency of concern. Andre

Andre - thank you, it sounds like I finally explained it properly. So, if I understand your answer, because the "pocket" created between the two sides of gypsum will be open to the attic space above the studio (and ultimately, by ridge and soffit vents to the outside), it will not create an effective "spring" (as in the mass-spring-mass) to cause resonance in the frequency range of audio, so I simply don't worry about it?

bwilkinson wrote:

Andre - thank you, it sounds like I finally explained it properly. So, if I understand your answer, because the "pocket" created between the two sides of gypsum will be open to the attic space above the studio (and ultimately, by ridge and soffit vents to the outside), it will not create an effective "spring" (as in the mass-spring-mass) to cause resonance in the frequency range of audio, so I simply don't worry about it?

The important thing is you do not have to worry about it. Read my reply again. There is no mention whatsoever of the attic being open. There is no mention of there not being a MSM resonance. Because the attic is such a large volume, the MSM frequency is very low. So low that is not significant for sound isolation. If that does not seem straighforward, welcome to acoustics. :? Andre

Okay, I'll trust it. I was simply attempting to understand the "why" of it.

So, if I understand your answer, because the "pocket" created between the two sides of gypsum will be open to the attic space above the studio (and ultimately, by ridge and soffit vents to the outside),

Maybe I'm really dense, but I still don't understand what you are saying. How can both sides of a sheet of drywall both be facing the attic space? I really suggest that you should post a 3D SketchUp model of your design (.skp), since what you are describing is ambiguous, and could mean several different things.

it will not create an effective "spring" (as in the mass-spring-mass) to cause resonance in the frequency range of audio, so I simply don't worry about it?

Not really correct. Any time you have a pair of large, flat, massive surfaces facing each other across an air gap, you have an MSM system. The spring is there (the air space) and the two masses are there. Therefore you always will have an MSM system, and it always will have a resonant frequency. Or rather, an MSMSM system in yoru case, since you seem to be describing a 3-leaf system. What André is saying, is that for a very large air gap (several feet) the resonant frequency will be so low that it doesn't matter. Because the air gap is so big, the combined resonant frequency will be less than half of the lowest frequency that humans can here, so the 3-leaf effect will not be increasing the resonance dip to an area of the spectrum that is high enough to be of concern. That is assuming that you actually are describing a three-leaf system with a very large air gap. Your description MIGHT be talking about that, but it also might not. Only a clear, detailed 3D model can tell for sure... - Stuart -

Soundman2020 wrote:

That is assuming that you actually are describing a three-leaf system with a very large air gap. Your description MIGHT be talking about that, but it also might not. Only a clear, detailed 3D model can tell for sure...

You expanded on my short expaanation wonderfully. The part I quoted is most important to the OP. A clear model (drawing) of what is being discussed will remove any ambiguity. Clearly, Andre

Stuart - the updated file is attached, zipped. I have placed the gypsum in the area in question, and updated to the best of my ability. The "pocket" I was talking about is the space between the studs, covered by drywall both on the studio side and the apartment side. However, it is not completely closed in the studio side. In the attic space of the studio, the studs are exposed. So, the "pressure" that would normally build due to vibration of the drywall in a sealed stud wall has an escape route - into the attic of the studio. This makes an effect of a larger air gap between the two sides of wallboard. Correct? Also, I believe we are saying the same thing - but my nuances were missed. I did not mean to say that it did not create an MSM resonance - just not one in the {effective} audio range. By saying that it did not create an effective spring, effective was meant to be key.

the updated file is attached, zipped. I have placed the gypsum in the area in question, and updated to the best of my ability.

OK, well I'm not seeing a three-leaf in the roof at all! I'm only seeing a 2-leaf: You have the roof itself, (which you show only as shingles with no deck underneath but I guess in reality there will be an 18mm plywood deck, and probably some beefing underneath): that is one leaf, your outer leaf. Then you have 2 layers of drywall under the joists, for your ceiling: That is the other leaf, your inner leaf. There's no 3rd leaf there, that I can see. BUT!!!! that's the roof. You have a major issue with your walls: What I DO see is that you have no inner leaf walls at all! :shock: Both your roof (outer leaf) and ceiling (inner leaf) are resting on the one-and-only same single stud frame wall! So you have zero isolation there, basically!!!! :shock: :shock: :!: To fix that, you need to build a SEPARATE stud frame for your inner leaf wall. You correctly have your roof resting on the outer leaf, and that's perfect. But you need to build a totally separate, decoupled stud frame just an inch or so inside of that, and your ceiling joists will rest on that inner frame, NOT on the outer frame. There must be no contact at all between the two frames. Nothing can touch, not even a single nail. I think that might be the source of your confusion. Once you fix that, it should all fall into place.

The "pocket" I was talking about is the space between the studs, covered by drywall both on the studio side and the apartment side.

That should never happen: With a proper MSM build, you should never, ever have a single set of studs that has drywall on both sides. If you do that, your leaves are coupled and your isolation is severely compromised... You need to use separate frames, with drywall on only ONE side of each set. - Stuart -

I will reiterate. Right now, I am only working on the outer leaf. I have not begun to design my control room. I have not begun to design my live room. I have not begun to design my iso booth. I have created a room - a shell, that in the future, I will place in it a separately designed control room, with separate walls. I will also place in this shell a live room. I may also place a small iso room, if I can get it to fit. However, right now I am mostly concerned with getting the shell properly sealed with one leaf. From what you are currently telling me, I am now afraid that I am not doing this. From what I have read on this site, the outer leaf needs to be sealed. Using the roof as the outer leaf is a bad thing, from what I understand, because code requires full venting to eliminate moisture buildup and ultimately rot and mold. This is a full air gap that would allow any sound vibrations right on through. So, my outer leaf was the two sheets of drywall on the ceiling, the two sheets of OSB on each of the walls around the studio shell, the two sheets of drywall between the garage and the studio (on the garage side of the studs), and the two sheets of drywall on that same studded wall, on the studio side, located from the bottom edge of the top plate, continuing upward past the floor joists of the second floor, and ending at the peak of the vaulted ceiling. I understand that if my inner leaf were the ceiling, it would be useless. The vibration from the sound would simply travel through the ceiling trusses. Please understand that I placed the look of the siding, roofing, etc all in there just to make it easier to see. I did not intend for those to be construed as the thickness of the actual siding and roofing. So, back to my original question - understanding that I will, in the future, place my walls for my room-in-room construction later on, once I get the shell properly designed - is this sufficient for the ***outer*** leaf? Guys, I really am not trying to be difficult. I understand that you are all taking your time to help me, and simply, you don't have to - you choose to. However, I have been designing the same way for fifteen years, and it is very difficult for me to change that. As I build my design, I start from the outside and work inward - one step at a time. If I need to modify the outer component to fit something inside as I go, I do that. However, I cannot simply put the whole design together, then work through all the details. I will miss something - I've seen it happen. So, right now I work on the outside - what will keep rain off my body, and is the maximum space I believe I can afford to build. Then I need to seal it, and make sure it's sealed properly (in this case, both from weather and sound). Then, I build my interior space, one room at a time until they are all complete. I have a general concept of the room sizes and shapes, and am building from the outside in with those in mind. However, right now I'm only focusing with the "outside." I have to have a building before I can make a studio.

"This will then mean that I would either have to place two sheets of gypsum on that wall inside the apartment, as well as two sheets of OSB on that outside wall (above the roof trusses), or I would have to place two sheets of gypsum on the studio side of that wall, creating a three leaf system." I think the confusion, Bob, is orientation. To be fair, there is not one room built that does not have minimum one three leaf. That is the one that exists between the floor and the ceiling and the roof/upper floor. It's kinda like the notion that there is a spider within three feet of where ever you are in your home. Your concern is not with the ceiling/roof as is being posited on, correct? Your main concern is that there is not going to be enough >isolation< between the upper wall from your recording room to this apartment. Horizontal, that is the view I see based on your graphics and suggestions, not vertical. But even the isolation attempts can be dismissed when that truss is attached to the upper framing of the apartment. When you consider that low frequency is going to be the agent that creeps into the apartment and flanking is the road it takes, you can build that area up as heavy as you want but the gremlins will still find water. Brien

Brien, you are exactly correct in my concern - and maybe it's simply a case of me over analyzing it - it's been known to happen... :roll: I think I understand now, and will continue design. One other thing that I had considered, and this may be a completely loopy idea (I've been known to have those, too!), was with the concrete floor. Of course, when I build my load bearing building, state code requires that I take the foundation below the frost line (in my case, 42" - ugh) for any structure over 400 square feet. However, structures under 400 square feet can simply be built on a pad. When I build my control room, my live room, and (if it occurs) my iso booth, each of those would easily be under that 400 square foot area. So, I was considering pouring the concrete pads for the floor in smaller sizes, with elastomeric expansion joints between them. Each pad would be the size of the individual room, ie the control room would be on one pad, the live room on one pad, (including the stud walls, of course) etc, all encased inside the foundation wall of the building itself. Or is the flanking path through the concrete (sitting on solid soil) so minimal that I'm putting entirely too much work and analysis into this? In addition, of course, it could then allow for varying levels of settling over years, and could cause more structural issues than it would solve with sound isolation. If I'm totally off base, let me know - I can take it. Thanks everyone!