Detached shop conversion

Greetings! This is my first post, but I've lurked for some time doing research for my upcoming detached shop conversion. I'm purchasing a house with a 20'x17' shop. Will be converting it into an live room, primarily for my drumming and some solo recording projects. For now at least mixing will take place in the room as well, but mostly I'll just be using it for practicing. Need a lot of open space to accommodate several large drum kits. I'll be doing much of the work myself, with the help of my father in law who is a professional contractor (have to keep him reigned in on some acoustic myths though!). Have read Rod Gervais' book pretty thoroughly, so I have a good understanding of isolation techniques. About the room: - 20'x17' - Gabled(?) roof with truss, as seen http://www.carpentry-pro-framer.com/images/common-roof-truss.png. - Approx 8' "ceiling height" (no ceiling currently installed) - Concrete slab foundation - Studs with 16" spacing, T1-11 siding, currently pink insulation covered by crappy wood paneling - 1 window to be removed - 1 skylight Goals: - As much open space as available (one big room) - Great isolation (I play loud, probably 120db, neighbors are 30' or so away). Don't need to play all night, but would like it to be as quite as possible during reasonable hours. - Will figure out acoustic treatments later, concentrating on isolation for now - Budget under $4000, including treatments (hopefully!) Current plans: - Rip out crappy 3rd leaf wood paneling. Hopefully the existing in wall insulation is ok for the outer leaf. - Construct "room in room" with 1" (enough?) spacing between existing studs and new framing (using 2"x4" framing, 24" spacing) - Fill new framing with Roxul bats. - install 1/2" drywall, green glue, then 5/8" drywall (plus tape/mud/caulk, etc) - Install Fantech SH704 fan in "attic" for ventilation, isolated by sealed MDF box. - Replace current outer door with, install a second inner solid core door with appropriate sealing door jamb. - Not sure how to deal with ceiling. Questions: Walls - Is 1" space between new and existing framing enough? I'm losing close to a foot all around with that, so would like to find the right balance here. - Do I need a solid core door for the outer door as well as inner? I think Rod's book said yes, but father in law says no. Ceiling Father in law tells me that the ceiling can be raised by moving the truss up (basically installing new truss members higher, then cutting away the lower parts of the original). Higher ceilings are great for drums, so I'd like to to this in some fashion, particularly without creating a bunch of new corners. I'm considering either: - A sloped ceiling (8' at low end, on the 21' side, to as high as I can get on the other 21' side, maybe 10' - A partial gabled ceiling (no idea if that's what it's called), like /---\ (ascii!) - Stick with the 8' (minus a few inches for isolation materials) flat ceiling Any thoughts about which of these might be acoustically preferable? Concerns regarding the construction, ability to hang ceiling clouds on the sloped ceiling, etc? Is it best to hang the ceiling with RC1 in a case like this? Skylight Obviously the skylight to the inner room has to go for isolation. Can I leave it up in the attic space I'll be creating, or is it going to cause issues? HVAC - I figure the Fantech SH704 will be more than adequate for ventilation. I plan to install it in the attic space, run a zig-zag (is L shape enough?) ducts to the outside vents, and another zig-zag (L shape?) to vents in the room. What's the best placement for vents for fresh in/stale out in the room and the outer walls? - It's not super cold here in the winter, but I believe code requires some sort of heat. Is an in wall cadet heater suitable? Yeah, I should probably check local code here... That's all I can think of for now, I'm sure there will be more. I hope to start framing this coming weekend, so wouldn't complain if folks were kind enough to offer suggestions soon. ;) I'm attaching a crapping floor plan (haven't figured out Sketchup yet) which might help explain the basic plan of my wall construction.

Hi "Bawoo". Welcome! Some comments:

"T1-11 siding, "

What is "T1-11 siding"? Maybe its well know where you are, but I have no idea. Can you describe it in detail? If that's your outer leaf, I assume it is very massive. dense and rigid?

Great isolation (I play loud, probably 120db,

:shock: That's loud, for sure! OK, assuming your local noise regulations are like most places, you need to get that down to around 40 or so. That means 80 dB of isolation! :shock: :shock: We are talking SERIOUS construction here if you want to play that loud and also abide by the law. 80 dB TL is tough to do. 1) How did you determine how loud you are? 2) What do your municipal regulations say about the legal limits? 3) If you are not aiming for the legal limits, what number are you aiming for?

Hopefully the existing in wall insulation is ok for the outer leaf.

Hopefully, but you might have to take it out anyway, so you can seal the outer leaf properly. It has to be sealed airtight. Also, you might need to beef up that outer leaf form the inside, to get the levels of isolation you are talking about.

Construct "room in room"

:yahoo: Yup!

with 1" (enough?) spacing between existing studs and new framing

1" gap between framing? For 80 dB of isolation? I'd say that's not enough.

install 1/2" drywall, green glue, then 5/8" drywall (plus tape/mud/caulk, etc)

Why 1/2" plus 5/8"? Not necessary, no great benefit, and you need MASS for your wall to get those levels: you don't need to be worried about coincidence dip. I'd go with both layers of 5/8", and you might even need a third layer.

Replace current outer door with, install a second inner solid core door with appropriate sealing door jamb.

Multiple seals. Each door needs at least two independent seals, probably 3 for your case, all around all 4 edges: sides, top and bottom. Completely airtight.

Is 1" space between new and existing framing enough?

For 80 dB TL? Probably not!

- Not sure how to deal with ceiling.

What is up there already? The ceiling has to be the same as the walls: at least two x 5/8" with GG. That's assuming that the existing roof already has stacks of mass on it, and doesn't need beefing up.

Do I need a solid core door for the outer door as well as inner? I think Rod's book said yes, but father in law says no.

Yes. You are right. Rod is right, father in law is not right. Hollow core and foam-filled doors are practically worthless, acoustically, even for a normal build. But to get 80 dB of TL you are going to need very massive doors, with 3 seals on each door and a large air gap.

- A sloped ceiling (8' at low end, on the 21' side, to as high as I can get on the other 21' side, maybe 10'

That would be my plan. It gives you a good start for your control room, if you want to go with an RFZ design.

I hope to start framing this coming weekend,

:shock: :?: :?: Are you SURE you are ready for that??? You are asking some pretty basic questions here, and very little of what you are talking about is on your plans. To my mind, it doesn't sound like you are ready to build anything yet! I'd start by getting a sound level meter and measuring your REAL levels on your drum kit, measuring how much isolation you already have, measuring the levels at your neighbors' houses, and checking your local regulations to find out what the limits are: Only with REAL measurements in hand can you decide on your isolation plan. Once you have a number, check IR-761 and IR-766 for possible construction methods, to find one that will get you that level of isolation. Then, and only then, can you start framing. My 0.02 - Stuart -

Thanks much for the quick reply Stuart. Let's see if I can make a sensible inline response...

Soundman2020 wrote:

What is "T1-11 siding"? Maybe its well know where you are, but I have no idea. Can you describe it in detail? If that's your outer leaf, I assume it is very massive. dense and rigid?

It's definitely not particularly massive. It's semi-cheap siding used in the States, basically an OSB manufactured wood product, 5/8" thick I think. Roughly equivalent in density to plywood.

Soundman2020 wrote:

Bawoo wrote:

Great isolation (I play loud, probably 120db,

:shock: That's loud, for sure! OK, assuming your local noise regulations are like most places, you need to get that down to around 40 or so. That means 80 dB of isolation! 1) How did you determine how loud you are? 2) What do your municipal regulations say about the legal limits? 3) If you are not aiming for the legal limits, what number are you aiming for?

Perhaps I overestimated here, going from memory of readings a guy at church took while I was being noisy. I haven't done any readings. I can tell you that I play rimshots much of the time, and generally bash as loud as a drummer can (tastefully of course! :)). I guess we're mostly concerned with kick drums and low frequencies, which are perhaps more like 100db (per Modern Drummer mag). I don't think I need 80db. Local limits are vague, something like "don't unreasonably create noise which can be heard in another home and would be unreasonably disturbing". In any case, I've been equally noisy in every house I've lived in for 25 years and never had problems, so I'm just trying to get to "better" here. 65db? As vague as the municipal code, I know... ;)

Soundman2020 wrote:

Bawoo wrote:

Hopefully the existing in wall insulation is ok for the outer leaf.

Hopefully, but you might have to take it out anyway, so you can seal the outer leaf properly. It has to be sealed airtight. Also, you might need to beef up that outer leaf form the inside, to get the levels of isolation you are talking about.

So one has to seal the OUTER leaf as well as the inner? Guess I missed this one in my reading. How is this different than building a room in a room somewhere else in the house, or in the basement? Of course I assume that the more sealed the better, but I won't what a mess I may be in if I keep the outer construction. As far as I can tell it's equivalent to the construction of the rest of the house, only using crappy wood paneling inside rather than drywall, and the ceiling is open to the rafter/truss.

Soundman2020 wrote:

1" gap between framing? For 80 dB of isolation? I'd say that's not enough.

How about for 65db? What would be a recommended or standard gap?

Soundman2020 wrote:

Bawoo wrote:

install 1/2" drywall, green glue, then 5/8" drywall (plus tape/mud/caulk, etc)

Why 1/2" plus 5/8"? Not necessary, no great benefit, and you need MASS for your wall to get those levels: you don't need to be worried about coincidence dip. I'd go with both layers of 5/8", and you might even need a third layer.

I had planned that after reading that the different thicknesses would dampen different frequencies. Not at all opposed to doing both 5/8" if the consensus is that's better. As to the third I think I'll plan on testing with two and seeing how it goes (could become a problem with door framing design though, hmm...)

Soundman2020 wrote:

Bawoo wrote:

Replace current outer door with, install a second inner solid core door with appropriate sealing door jamb.

Multiple seals. Each door needs at least two independent seals, probably 3 for your case, all around all 4 edges: sides, top and bottom. Completely airtight.

Yep, got it about airtight on both doors, just didn't articulate this clearly. Will go with solid core for the outer as well. I'm not sure what you mean by 3 independent seals though?

Soundman2020 wrote:

Bawoo wrote:

- Not sure how to deal with ceiling.

What is up there already? The ceiling has to be the same as the walls: at least two x 5/8" with GG. That's assuming that the existing roof already has stacks of mass on it, and doesn't need beefing up.

The ceiling is currently open to the underside of the roof. Obviously I have to insulate up there before building the ceiling.

Soundman2020 wrote:

Bawoo wrote:

- A sloped ceiling (8' at low end, on the 21' side, to as high as I can get on the other 21' side, maybe 10'

That would be my plan. It gives you a good start for your control room, if you want to go with an RFZ design.

There isn't going to be a control room, though it's possible as an add on later since the slab extends quite a ways out for a carport. For now I'm just looking at in room acoustics. My experience has been that high ceiling is always better for drumming (particularly when one of my kits sits rather high with 24" kicks and deep rack toms). Knowing that parallel surfaces are bad and corners are bad, I'm basically deciding between sloped, flat, or semi cathedral ceiling. I lean towards sloped (sounds like you agree), but am soliciting other opinions. :shot:

Soundman2020 wrote:

Bawoo wrote:

I hope to start framing this coming weekend,

:shock: :?: :?: Are you SURE you are ready for that??? You are asking some pretty basic questions here, and very little of what you are talking about is on your plans. To my mind, it doesn't sound like you are ready to build anything yet!

Perhaps, caution is oft the better part of valor. But given that I'm not necessarily looking for a specific level but rather a general "much better than none" I may be able to at least get a start. There's some demolition to do first too, I'll more than likely not get started quote that quickly (note that I said hoping :lol:). Thanks again for your input! I'll look into IR-761 and IR-766. -Peter

Hi Peter! (Much better to put a name to a handle, then just a handle!)

It's definitely not particularly massive. It's semi-cheap siding used in the States, basically an OSB manufactured wood product, 5/8" thick I think. Roughly equivalent in density to plywood.

OK, you probably will want to beef that up, to get good isolation. There's a technique commonly recommended here which allows you to do that without touching the outside: Once you get your "lousy paneling" off the inside of the room, take out the insulation (and keep it for re-use, if it is good), exposing the studs and the inner surface of the T1-11. Seal that if you can, then cut strips of 5/8" drywall to fit neatly between the studs, up against the surface of the T1-11. Hold that in place with cleats, and caulk all around the edges for an air-tight seal. That gives you a lot of extra mass on your outer leaf. You can do yet another layer in the same way, if you really need high levels of isolation.

So one has to seal the OUTER leaf as well as the inner? Guess I missed this one in my reading.

Yup! Both leaves must be sealed, airtight. This is not to create the MSM system, as people sometimes think, but rather simply to optimize it, but more importantly to "stop sound getting out". Even a tiny crack under the wall or around the edges can be a major sound leak, and compromise your isolation. If air can get through, so can sound. You need to seal all cracks on both leaves. You want to totally hermetic seals for maximum isolation.

How is this different than building a room in a room somewhere else in the house, or in the basement?

It's exactly the same: For maximum isolation, both leaves of the MSM system need to be fully sealed, regardless of how or where you build it. The principles of two-leaf "room-in-a-room" construction are the same everywhere.

but I won't what a mess I may be in if I keep the outer construction.

Well, if you beef up that outer leaf, you can make sure that your seal on the "beef" layer is perfect, but there's an underlying principle here that I'm sure you have heard of: Murphy's law. Murphy just LOVES studio builders, since there are just so many things that can go wrong! So the idea is to seal twice, even where once is really enough. So if you can, I'd still try to seal the existing T1-11 layer before you add your "beef", then seal the beef as well. That way, the gap that you didn't see in one stud bay on the T1-11 will be covered by the seal on the "beef", and the gap that you missed in another stud bay on the beef will be covered by the underlying seal on the siding. Are you getting the impression that seals are important? :)

How about for 65db? What would be a recommended or standard gap?

My standard answer: "It all depends." ! :) What many people don't realize is that a room-in-a-room studio is actually a tuned system. The two leaves and the gap between them form a resonant system. As you probably know, resonant systems are really lousy isolators at the frequency they are tuned to. But they are also very good isolators at higher frequency. So the trick is to tune the resonance to a frequency that is so low that it doesn't matter. It turns out that the system will not isolate at all in the region from the resonant frequency (call it "F0") up to 1.4 times that (F0 x 1.4). From there up to 2 x F0 it isolates somewhat, above 2 x F0 to 3 x 30 it gets pretty good, and above 3 x F0 it is great. So the trick is to tune the system to no more than half the lowest frequency that you need to isolate. So if you are recording female vocals, then tuning the wall to 75 Hz would work fine, since most of the energy in female vocals is above 150 Hz. For male vocals, you might want to tune the wall to 50 Hz, for the same reason. But for a small kick drum you'd want it tuned below 40 Hz, and a larger one below 35. For the bass guitar you'd need to get below 20, and to cover the full range of human perception (20 Hz to 20 kHz) you need to tune your wall to below 10 Hz. That's actually pretty hard to do. So how do you tune it? There are two major items in the equations that define how the wall behaves: The mass on each leaf, and the size of the air gap. There's also a constant that changes depending on whether you put insulation in t he gap or not. To DECREASE the resonant frequency, you can either INCREASE the mass on both leaves, or INCREASE the size of the gap, or both. So the question is: How low do you need to go? If you have a spectrum analyzer (many DAWs do) then you can play some drums and check out how low you go. If not, you can "guesstimate". So that figure (the lowest frequency you need to isolate) will define the amount of mass and/or size of the air gap. If all you can afford is a 1" gap between frames (implying a roughly 7" air gap) then you need to put more mass on both leaves. If you can afford a larger air gap, then you don't need so much mass. To give you an idea, two layers of 5/8" drywall on each side of a 7" air gap (total 4 layers) will get you a resonant frequency of about 29 Hz, so your wall will not isolate at all until 41 Hz, isolate reasonably above 58 Hz, and isolate well above 87 Hz. Is that enough? That depends on what you need, in terms of your lowest frequency. There's one more thing you can do to improve that: damping. If you damp the resonance of the MSM system, that improves isolation considerably. You damp by filling your wall cavity with porous acoustic insulation, such as mineral wool or fiberglass. If you did that to the above wall, resonance would drop to 21 Hz, the wall would not isolate until 29 Hz, isolate reasonably above 42 Hz, and isolate well above 62 Hz. Much better.

Perhaps I overestimated here, going from memory of readings a guy at church took while I was being noisy. I haven't done any readings. I can tell you that I play rimshots much of the time, and generally bash as loud as a drummer can (tastefully of course! :)).

OK, a loud drummer can usually hit 115 dB without trouble. Maybe 117 or so if he's really "inspired". But 120 is pushing it! I've never seen a drummer that loud. On the other hand, I've seen very disciplined drummers who can keep a fairly consistent 95 dB and still sound great! Which brings up the first point: You can reduce your isolation requirements considerably by playing quietly. :) If you can drop your level from 115 to 105, then you just dropped your 2energy absorbing" needs by a factor of ten. Your wall only needs to stop one tenth of the energy at 105 that it does at 115. If you can play even softer, at 95, then your total reduction factor is one hundred. At 95 db you only need to absorb one hundredth of the energy that you would have needed at 115. Surprising, but true. So playing more gently is the way to go to reduce your isolation needs.

I guess we're mostly concerned with kick drums and low frequencies, which are perhaps more like 100db (per Modern Drummer mag).

Sounds about right. But I don't know too many sings where you only play the kick and nothing else! :) Add the snare, the hi-hat and a couple of cymbals all ringing together, and you are more like 110 db, spread across the entire spectrum.

I don't think I need 80db.

Neither do I! :)

so I'm just trying to get to "better" here. 65db?

That sounds far more realistic. So assuming 110 dB for your drum playing, 65 dB of isolation will get you down to 45 dB outside. sounds like a good, do-able goal. Page 348 of IR-761 shows something that will get you there: two layers of 16mm Type X drywall on two sets of 2x4 studs (total 4 layers), a one inch gap between the frames, a total of 7 inches of fiber glass insulation in the cavity. Theoretically, that gets you STC-67. However, STC is no good for measuring isolation in studios, as it does not take into account the most important frequencies. Fortunately IR-761 also has a graph and table that show the actual measured response of a real-world lab test down to 50 Hz, and it is good, agreeing with MSM theory. If you add Green Glue to that wall, it will do fine for what you want. BUT! (And this is a big "but"): that's just the wall. You need to do the ceiling identically, and also the doors and windows. Everything needs to be done to the same level. If your walls are good for 65 dB but your door is only good for 45 dB, then you get 45 dB isolation. Period. No matter how good your wall is, your isolation is defined by the weakest link.

I had planned that after reading that the different thicknesses would dampen different frequencies.

Well, yes no kinda sorta but not really! :) Each type has its own resonant frequency, sure, but it's reverse of what you assumed: each type has BAD isolation at its own coincidence frequency, so with different types, the coincidence dips do not line up. But coincidence is not a problem for 5/8" drywall, since it occurs at mid-high frequencies (above 2 kHz), in the region where isolation is already excellent. Sure, by using two different types of drywall you do spread the dips, but in a region of the spectrum that doesn't matter. On the other hand, by using one thinner than the other, you reduce the total mass, and therefor the total isolation. Also, the thinner one has much worse properties at low frequencies, where stiffness is important. So you gain isolation where you don't need it, and lose isolation where you do need it. That0s why the recommendation here is to go with two layers of the thickest, most dense stuff you can get.

As to the third I think I'll plan on testing with two and seeing how it goes

That's fine for the inner leaf, but how are you going to get access to the outer leaf to add the extra layer of "beef" between the studs, once the inner leaf is complete? :) For optimum performance, you need the same mass on each leaf...

I'm not sure what you mean by 3 independent seals though?

simple! You seal it, then you seal it again, then you seal it one more time! :) Seriously, for this type of door, you build it in layers, with each payer being a bit smaller than than the previous one. So the first layer has a seal all around the edge, that butts up tight against the jamb. The the next layer has another seal all around its edge, that buts up against the second jam, and the third layer on the door has yet another seal that butts up tight against the third jamb. Each seal runs in an unbroken line all around the edge of the door: 3 complete seals.

The ceiling is currently open to the underside of the roof.

That's what I'm getting at: what is the roof made of? It is your outer leaf, so it needs to be beefed up to the exact same level as the outer-leaf walls: the equivalent of at least 2 layers of 5/8" drywall. And, of course, it needs to be sealed... Hmmmm.... Ooops! Problems! I think you can figure where this is going...

My experience has been that high ceiling is always better for drumming

Oooohhhhh yeahhh! Very true! Room height and room volume are critical for good drum sound. And if you plan to record your drums, even more so.

Knowing that parallel surfaces are bad and corners are bad,

Depends.... :) Parallel can be fine, if treated properly, and corners are so bad that they are good! Best possible place to put bass trapping, precisely because it's where all the "bad things" (room modes) come together to party!

But given that I'm not necessarily looking for a specific level but rather a general "much better than none" I may be able to at least get a start.

Maybe.... but it's an awful lot easier to demo the "lousy paneling" and beef up the outer leaf BEFORE you put up a bunch of studs just an inch away.... :) Demo and beefing up can take quite a while... - Stuart -

Ok, I'm gaining a lot of clarity here, thanks much for the detailed info! After your talk about beefing up the existing outer walls and roof I went back to Rod's book and see where I missed this discussion before. Oiy...adding slices of drywall to between the studs is going to be a ton of work! But I can see now where it's well worth it. So the general idea is to use finishing nails at an angle to wedge the drywall in place, then cleats after caulk for final strength, yes? Do I understand correctly that it's best to try to match mass of both leaves, thus try to get the same mass on the outer walls and inner? So a decision about whether to use 2 layers of drywall inside will drive how much drywall mass I add to existing walls? (1 layer added if I go with 2 inside, or 2 added if I go with 3)

OK, a loud drummer can usually hit 115 dB without trouble. Maybe 117 or so if he's really "inspired". But 120 is pushing it! I've never seen a drummer that loud. On the other hand, I've seen very disciplined drummers who can keep a fairly consistent 95 dB and still sound great! Which brings up the first point: You can reduce your isolation requirements considerably by playing quietly. :) If you can drop your level from 115 to 105, then you just dropped your 2energy absorbing" needs by a factor of ten. Your wall only needs to stop one tenth of the energy at 105 that it does at 115. If you can play even softer, at 95, then your total reduction factor is one hundred. At 95 db you only need to absorb one hundredth of the energy that you would have needed at 115. Surprising, but true. So playing more gently is the way to go to reduce your isolation needs.

Hmmm, not sure how much discussion this is worth. ;) Certainly playing softly reduces isolation requirements (perhaps the one thing in all of this in which intuition actually matches reality!). Jimi could have turned down his Marshalls and been quieter too, but he wouldn't have sounded like Jimi! I can keep a consistent 95db and sound great, where appropriate, and much louder where appropriate too! There's no way to fake the throaty sound and response of rimshots on the snare or a tight tom, or to get a 20" medium crash to open up without laying into it. Playing hard isn't just about volume, but about the sound and response of the instrument...nature of the beast I'm afraid. I now understand that mass is more important than tuned frequency response in my situation, so I'll go with all 5/8" drywall, thanks for clarifying. As to beefing up the ceiling (in particular) and outer walls, any thoughts on attaching the 2 layers of drywall together BEFORE attaching to ceiling? Seems like it might be easier as one doesn't have to do the work of raising the material twice. But perhaps not because it will be more difficult to manage (heavier) and caulk. Yeah, you're thinking "how come every n00b tries to reinvent the wheel??", but it seemed worth asking. So as to corners, your suggesting that both sloped and semi-cathedral (/---\) have advantages, the one being higher and the other giving you an additional opportunity to add more bass trapping? This one is a big and upcoming decision point for me, as we'll be working on the trusses one way or another this weekend. Hmmm...it seems that even if I do a sloped ceiling I'll end up with a second angle where the main slope hits the roof angle (no way to ascii this! I'm attaching a rough pic)

Do I understand correctly that it's best to try to match mass of both leaves, thus try to get the same mass on the outer walls and inner? So a decision about whether to use 2 layers of drywall inside will drive how much drywall mass I add to existing walls? (1 layer added if I go with 2 inside, or 2 added if I go with 3)

Well, you don't HAVE to, but that's the optimum arrangement. There's a slight disadvantage if the mass is different. So if you can, then yes, keep the same mass on both leaves.

any thoughts on attaching the 2 layers of drywall together BEFORE attaching to ceiling?

Well, you can't glue it together, unfortunately, as that totally changes the acoustic characteristics. But you CAN build "modules" on the ground with some framing and both layers of drywall, then lift them and bolt them in place, to some type of central beam. That is a possibility. But then you are lifting a couple of hundred pounds each time! two layers of drywall weights about 24 kg per square meter, so a module with 4 sheets on it, plus framing, is going to be well over 100 kg: Are you feeling strong? :) Some people do that using drywall lifters or some other method (a dozen buddies, and a case of beer is know to work as well...) but personally I'm not to keen on lifting heavy things above my head that could kill me if someone slipped or something broke on the drywall lift... On the ceiling shape: I can't say why, but I think I prefer option "A". - Stuart -

Appreciate the quick reply as always! So anyone want to come over and help install 100+ drywall panels? :shock:

Bawoo wrote:

Appreciate the quick reply as always! So anyone want to come over and help install 100+ drywall panels? :shock:

ahhhh .... not really :roll: :lol: just following along with your thread ... and if i may ... When I was 'beefing up' my basement ... I had to go into 'what is the flooring' above. Between the floor joist we had to add 2 layers of 5/8" drywall. As you suspect ... that was NOT a fun job ... :twisted: Once we got the 1st layer up, I went in caulking & sealing all the edges & seams. THEN ... We had to do it ALL again, but this time, we added GreenGlue to the sandwich. Once that was done, caulking/sealing again. THEN ... using 1x3 furring strips, we secured the runs of drywall. This is a safety precaution ... I forget the actual TONNAGE that would be above!!! Oh, and THEN I re-caulked the furring strip edges. Why I mention .... getting multiple seals seems a 'major theme' the "GURU's " teach. The 'concept' also seems to carry similarities throughout the building process. Oh ... did I mention how HEAVY this stuff is !! After u get it done ... you will be happy. I hope to be able to put my drum kit to uninhibited use :D

Thanks for the additional detail RJ. This is pretty much my plan at this point, at least for the outer walls. Looking through some other builds for ceiling/roof ideas before I decide how to deal with that. Question for the community: Anyone have any experience with Certainteed Silent FX? http://www.certainteed.com/Products/340906. The local drywall guy told me about it when I called for some material pricing. It's pretty expensive, but might be worth considering as a time saving measure. I haven't looked over the specs yet, I'm off to read up right now.

Howdy, I'm back to humbly ask more advice. ;) The good news: Purchase of the house went through! The room is now in my possession, and demo of the HUGE quantity of wood paneling, shelving, and cabinets that were there is finished. I now have a car sized mountain of wooden trash in my carport. That's gonna cost me some cash to get rid of! Built a gate to keep the dog in the back yard too... :mrgreen: After looking again at the trusses and shallow angle of the roof I'm going to stick with a horizontal ceiling, as there's just not enough room up there to gain much by redesigning the truss (or money and time to do so). So here's my current dilemma. I plan to beef up the outer walls and roof with a layer of drywall inside as described (seems like it will be a ton of work!). But how to I deal with the ventilation in the soffits? There are currently vents in every other rafter bay to the outside, to keep airflow in the rafter area after installing the ceiling. How do I maintain ventilation above the ceiling while keeping this area air tight? I don't want to build a second inner ceiling (third leaf=bad). Do I need a fan system that vents the upper area in addition to the inner room? Rod Gervais seems to describe a similar situation in his book on pages 284-288, but I don't exactly get it. He describes "proper vents", I can't seem to determine exactly what they are. Also, his figure 10.22, which seems to describe exactly what I need, is a booboo, a repeat of an earlier diagram, not the one he describes in his text. I'm a bit stuck here, and very much appreciate any advice! :shock: One last question for today - when I build the framing for the inner room (17' x 21' approx), how do I stabilize it so the walls don't shift? The dimensions are too long for joist framing to keep the walls from shifting (3rd dimension stabilization, if that makes sense). Without joists, I had planned on attaching the ceiling to the trusses with RC2. Father in law suggests a few attachment points, attaching the inner framing to the truss, but the obvious problem here is transfer of vibration to the outer leaf with direct contact. Any suggestions? I'm in a bit of a rush now, but will try to post some pictures tomorrow if the above doesn't describe the situation well enough. Please ask if you need more info.

Incorporate silencers in your soffits for handling the ventillation as it enters and exits. Regarding the diagramm 10.22, I got in touch with Rod (on Gearslutz) and he sent me a copy of the missing diagram. Most of the information you will see on the following diagram (facing page to 10.22).

But how to I deal with the ventilation in the soffits? There are currently vents in every other rafter bay to the outside, to keep airflow in the rafter area after installing the ceiling. How do I maintain ventilation above the ceiling while keeping this area air tight?

I'm not sure I understand your question! You are talking about soffits in the sense of flush-mounted speaker panels, right? Since those are INSIDE of the inner leaf, the only place you can vent them to is back into the room. The normal way of doing that is to leave an open path through the entire soffit, starting at the base, up past the rear of the speaker (where the heat sink is), then continuing up another meter or so, and out through a slot cut in the front panel itself. Take a look at John's design for soffits: he clearly shows how to do that. Or if you are talking about "soffits" in the sense of "under the eaves, outside the building", then those have to remain, since they are part of the roof ventilation system. Of course, that compromises your isolation... Not much you can do about that, except build a third leaf, but doing it properly in order to compensate suitably. If you need very high levels of isolation, that third leaf might indeed be the only solution.

when I build the framing for the inner room (17' x 21' approx), how do I stabilize it so the walls don't shift? The dimensions are too long for joist framing to keep the walls from shifting...

Once again, I'm not sure I understand the question: the framing MUST be bolted (or nailed) to the sub-floor, regardless of how long or short the wall is. That's what keeps it from shifting. If it is bolted down correctly, it cannot shift. Why would if shift in any case? do you live in an earthquake zone? There seems to be some confusion on this forum about how to frame the inner-leaf, and what keeps it strong structurally. The answer is simple: the exact same things that keep the outer leaf strong structurally! Both leaves are built the exact same way, so why would one be structurally sound an the other not? Both are firmly attached to the sub-floor, both have framing going up the sides and across the top ("roof" in the case of the outer leaf, "ceiling" in the case of the inner leaf, and both have drywall on one side of the framing. What's the difference? NOTHING! If the outer leaf of the house can stand up all by itself without shifting, and you build the inner leaf in the exact same way, then why would the inner leaf not stand up too? The framing is a 5-sided 3D cage, attached to the floor: all of the five "sides" hold each other in place. The walls brace each other at the corners, the floor braces the bases of the walls and the ceiling joists brace the tops of the walls. Framing the inner leaf is identical to framing the outer, and they both stand up for the same reasons. If you think you need extra structural integrity in sheer, then you can replace the first layer of drywall with plywood or OSB, which also gives you an additional advantage: nailing surfaces all the way around the room, wherever you need it!

Without joists, I had planned on attaching the ceiling to the trusses with RC2.

Well, if you don't frame the ceiling correctly (leaving the inner-leaf framing incomplete and unbraced), then yes you will have problem with the structural integrity of the wall framing. But why would you do that? Why do you not want to correctly frame the ceiling with joists attached to the inner-leaf walls? It won't save you money, it won't save you much space (if any) and it will compromise your isolation. In fact, it will end up costing you more money, as you will need sway braces to stabilize the wall tops, which also reduces isolation a little. So what is the reason for not framing the ceiling properly, with joists resting on the inner-leaf walls? - Stuart -

Soundman2020 wrote:

But how to I deal with the ventilation in the soffits? There are currently vents in every other rafter bay to the outside, to keep airflow in the rafter area after installing the ceiling. How do I maintain ventilation above the ceiling while keeping this area air tight?

I'm not sure I understand your question! You are talking about soffits in the sense of flush-mounted speaker panels, right?

Nope, talking about eh soffits vents under the eaves. I know I have to ventilate the area directly under the roof, thus my question. BriHar: any chance of getting a copy of that diagram? And can you describe the silencers for the soffit ventilation? Are you talking about mass incorporated silencer boxes, as one would build for HVAC ducts?

when I build the framing for the inner room (17' x 21' approx), how do I stabilize it so the walls don't shift? The dimensions are too long for joist framing to keep the walls from shifting...

Once again, I'm not sure I understand the question: the framing MUST be bolted (or nailed) to the sub-floor, regardless of how long or short the wall is. That's what keeps it from shifting.

Yep, I'm aware of the need to bold the framing to the slab. It's the sway/lateral support I'm concerned about. Should I use OSB or plywood sheathing to keep things square?

There seems to be some confusion on this forum about how to frame the inner-leaf, and what keeps it strong structurally. The answer is simple: the exact same things that keep the outer leaf strong structurally! Both leaves are built the exact same way, so why would one be structurally sound an the other not? Both are firmly attached to the sub-floor, both have framing going up the sides and across the top ("roof" in the case of the outer leaf, "ceiling" in the case of the inner leaf, and both have drywall on one side of the framing. What's the difference? NOTHING!

Yes, there's some confusion, hence my questions. ;) I hadn't planned on installing a joist type ceiling as a) I don't know how to do it and b) Father in law (who is both very helpful and somewhat ill informed about the specifics of this type of construction) didn't seem to have a way to build one, and suggested the "bad idea" of attaching the new inner framing to the trusses. It's not a question of saving money, it's a question of me being a musician not an architect (dammit Jim!). I realize it's perhaps a tall order to ask for what may be basic info, but one has to start somewhere. Can someone describe the method for framing the ceiling/joist structure for the inner room, or point me to some additional resources? Or give me a hint as to what terms to Google for? Here's a pic of the room (sorry for the fisheye view, it's snipped from a panorama shot). And for fun...a pic of the pile of demo trash: And a window we broke in the process. We were tossing wood debris into the carport adjacent to the shop through the window. The other side of the carport has windows as well, and my 6 year old niece managed a perfect spear shot right through one of them from ten feet away! Oiy!

Can someone describe the method for framing the ceiling/joist structure for the inner room,

For the new walls, you are going to build stud frames about an inch or so away from the existing walls. The framing for the new ceiling will just be joists set across the top of the new wall framing, in the exact same way that ceilings are built in normal rooms. Joists cross the top, resting on the framing for the new inner-leaf wall. You will need to calculate what size joists you need, based on the type of wood, the span, and the load. - Stuart -

Allrighty, I'm off to try to learn about ceiling joists... :shot:

I think I too misunderstood your ventilation question, and was indeed referring more to HVAC considerations. Not sure it would be right to distribute copyrighted material but if you send a short E-Mail to the following address, requesting the missing diagram, I'm sure he will send it along, hopefully when enough people ask for it he'll make it available on the Errata page of the URL provided at the beginning of the book (which currently has only some errata for the first edition). The address can be found in the appendix to the second edition (pg.340), second paragraph. You ought to register your niece for the Olympic javelin team :lol: edit:If this were a phone number, I would not want it listed...so I removed it for the same reasons. xSpace

Thanks for the heads up on Rod's email, I'll nag him for the diagram (though I think I may not need it at this point). I've pretty much decided on a ceiling attached to the trusses with RSIC clips, and was also pointed to the RSIC-DC04 to connect inner walls to existing framing to solve the sway issue and maintain isolation. Drywall guy should be coming soon with piles of the stuff so I can start adding mass to the outer layer between studs. Not really looking forward to that part, but I imagine it won't be so bad once I get started. Another question if I may: I re-read a bunch of stuff in Rod's book, looked through a number of sources online, and checked out a lot of other studio builds. I'm not really clear on the best type of insulation in the walls and method for installing at this point. I had planned on using Roxul Safe'n'Sound, but it looks like a lot of folks are just using some or another fluffy pink in the airspace in the MAM, and saving the "good" stuff for in room treatment. What's the recommendation here? And do I use faced or unfaced insulation? If faced, the paper should go against the drywall, yes? (paperside out between the outer studs, paper side in on the inner walls?) Thanks again for all the great advice you folks have been giving, this thread and some PM's have really been a tremendous help!

Bawoo wrote:

I've pretty much decided on a ceiling attached to the trusses with RSIC clips, and was also pointed to the RSIC-DC04 to connect inner walls to existing framing to solve the sway issue and maintain isolation.

I should probably add some clarification here. I did some research on new joists resting on the new inner framing. Because of the 17' span, I'd need something like 10x2 members for the joists! This would get really nasty with the ceiling space given the angle of the roof. Since decoupling via RSIC clips and hat channel specs out almost as good for isolation, it's the obvious choice. Still need to figure out how to deal with the venting (bird blocks and 2 roof vents) in the "attic" after installing the new ceiling. That's a lot of holes to leak sound given that this design has the roof a my outer leaf. I don't see how I could build a 3rd leaf because of the complex design of the truss (at least not without lowering the ceiling another 8" or more). Any more thoughts? Oh, and I got the insulation questions figured out I think. Plan to use existing insulation plus unfaced R-19 fiberglass in the new walls and above new drywall ceiling.

"Because of the 17' span, I'd need something like 10x2 members for the joists! " The proper explanation would be 2X10, and you will not span that far with any amount of weight on the ceiling. So you can talk like you know what you are doing, but you are still guessing..

xSpace wrote:

"Because of the 17' span, I'd need something like 10x2 members for the joists! " The proper explanation would be 2X10, and you will not span that far with any amount of weight on the ceiling. So you can talk like you know what you are doing, but you are still guessing..

Actually I looked it up, and 2x10 (yes, not 10x2) is the minimum for a 17' span, per http://www.awc.org/calculators/span/reversecalc/reversecalc.asp. I'm not guessing, I'm trying to learn. :) So can you clarify what you mean by "you will not span that far with any amount of weight on the ceiling"? Do you mean it's simply too long of a span to put significant weight (multiple layers of drywall) on the ceiling? That seems to be the part of the conundrum, which is part of my reasoning for using RSIC-1 clips attached to the trusses instead. Oooh, just found your site Brien, lots of new reading. Cool!

It means that you have several things to consider before you run off purchasing lumber. The live load/dead load for instance. You have to have an accurate count on how much weight you are going to place on the top side(the live load side) to access your live load. Then you have to calculate the weight of ALL the materials involved(the dead load) that will be imposed on this member...INCLUDING the weight of the lumber itself. Then you have to take into account if this is a 16 inch layout, a 24 inch layout, etc. THEN, the measuring procedure is from outside of wall assembly to the opposite outside of wall assembly. Having all that you may be able to come away saying "yea, I was right and that old fart needs a tune up" OR you will say "I am greatfull that kind and helpful older gentle man helped me from getting a BAD headache" Dig?

Thanks for the input Brien. I do understand the concerns about load, if not the exact details. Hate to have the ceiling fall on my instruments, or worse my head (though if the former happens I may wish I had been there for the latter!). It really appears at this point that separate joists for the inner room aren't a good option for me, again due to the lack of headroom and long span (would be easier if I wasn't going for one big room!). At this point the plan is to stick with RSIC clips attached to the trusses. I was checking out the inner roof in consideration of beefing it up with a layer of drywall. As does everyone else, I have nails poking through the OSB. I read somewhere that Rod suggested putting up a layer of rigid insulation between the OSB and drywall to deal with this problem. But then I still have concerns about ventilation of the attic space and the vents (roof vents and bird blocks) killing a lot of my isolation. In reading some other threads I see that some people are going with a 3rd leaf, attaching a layer of OSB and drywall in the cavities between the lower truss chord, as seen in On Purpose Productions build here http://www.johnlsayers.com/phpBB2/viewtopic.php?f=2&t=11485&hilit=nails+ceiling+drywall+beef&start=90. If I did this I'd only have about a 6-7" gap between inner ceiling and the 2nd leaf (roof being the 3rd). I'd appreciate any solid input/data on the isolation benefits of the above described method vs. beefing up the roof and building silencers for bird blocks/roof vents. Given that info I can work on the specifics of construction for whichever method seems best. I'm working on getting specs for the load bearing capabilities of the current trusses, which I need in either case.

@Xspace Hi Brien, I noticed you removed Rods E-mail address from my earlier posting. I understand your concern here, however I would point out that Rod posted this address to me in an open post on gearslutz, and it is still there, but more to the point, this E-mail address is openly published in the appendix to Rod's book (second edition). No problem, as the OP has the book so can find the address. I'll edit my earlier post to reference this.

Hey folks! I haven't posted anything about my build for a while, been working on tedious beefing up and design finalization. Just wanted to put up a brief note to share some of my excitement! :yahoo: I just got off the phone with a(nother) local structural engineer. I have received some rather large quotes from other engineers for evaluation of my roof trusses ($500-$1000!). Last call of the day, I finally got someone who wanted to HELP. She spent a good 20 minutes asking questions about my purpose and the trusses, offering advice and information, etc. The gist she'd rather not take my money when she's fairly certain my weight loads won't be a problem. She referred me to a guy at the building department in the city who likely has the info on these trusses on file, and would be involved in the permitting process. Bottom line was if Wade at the city thinks I need an evaluation she'd be glad to help me, but she fully expects the 12lb/sf load I'll be adding won't be an issue. Interesting to note, she pointed out that the biggest stress ever put on a truss is when they crane it up and install it, since the whole weight of the thing is being held in one spot. Anyway, I'm happy to discover that I probably don't have to spend a bunch of money to get someone to tell me I can build what I want to build (or worse, that I can't!). Will try to post some pics of my outer beef up and inner wall framing soon, which is mostly done.

"Interesting to note, she pointed out that the biggest stress ever put on a truss is when they crane it up and install it, since the whole weight of the thing is being held in one spot. " Maybe, but not the stress you are thinking about. Typically an operator will want his rigger to attache to the truss with two slings at points that allow the truss to not over-balance since the alternative will be one of two things, the first being use one sling and "hope" the truss stays balanced or tie the truss off on one end and hope the gusset plates and the framing material can take the weight of the truss in the flight overhead to the placement point. But I agree this would be the biggest stress :)