John Sayers' Recording Studio Design Forum Archive

Sweet. Don't forget to get all caulked up as you go along. That door, it's a thin aluminum and Styrofoam inner core type?

onpurposeproductions wrote:Its well on its way to being all 'massed up'!

Man, you sure did make a "mass" of that, didn't you!!!

Seriously, I bet you are really glad to actually be doing some actual construction, instead of chatting with friendly inspectors?


- Stuart -

Now the fun begins, right?

W

xSpace wrote:Sweet. Don't forget to get all caulked up as you go along. That door, it's a thin aluminum and Styrofoam inner core type?

The guy who took down the hardware said it was one of their doors - they would have installed it. He said its a steel door with a synthetic coating and blown in foam inside the panels. It certainly isn't thin and flimsy like I would imagine aluminum to be. The panels are 1.5" thick. I'd say its a good quality door designed with thermal insulation in mind (Canada - must be cold, right? ). I do still need to attach the panels together towards the middle of the door though to keep them from moving independent of each other.

Honestly, I wasn't sure about whether I would caulk at this point? Of course, I am trying to make it all one solid mass right up flush to the garage door, but then I'm going to build a wall right up against the door that spans the complete width of the garage and extends right up to the ceiling. This wall will get the same treatment as the other exterior walls (1/2" sheathing & 2 layers 5/8" drywall in the stud cavities with backer rod and caulk) and complete my outer leaf (except for the ceiling). So, caulking what I've done so far seems unbalanced with everything else.

Sure, it can't hurt but that caulking is expensive! I'll be going through a lot of it as it is. Thoughts?

WayneD wrote:Now the fun begins, right?

The fun can't fully begin until I actually have the permit. I've done all of this because I'm now confident I will get a permit but technically none of it is related to my build.

onpurposeproductions wrote: It certainly isn't thin and flimsy like I would imagine aluminum to be. The panels are 1.5" thick. I'd say its a good quality door designed with thermal insulation in mind (Canada - must be cold, right? ). I do still need to attach the panels together towards the middle of the door though to keep them from moving independent of each other.

Honestly, I wasn't sure about whether I would caulk at this point? ... So, caulking what I've done so far seems unbalanced with everything else.

It is a typical manufactured garage door in any event, nothing out of the norm, hell if you filled me full of foam of any kind I would seem fairly stiff myself Caulking, in this case, is not specifically a component of making a studio, especially in your door area. It is the difference between air,water getting into your house and not.

So I would consider it a necessary evil in this case. Me personally, I would even go so far as to take the individual panels of the garage door out, one by one down to the floor. Then get a high quality, exterior sealant and seal the connections between floor and door and then the connections that each panel have between them. And do the same for however this door is mating up to the vertical connections to your garage and the horizontal connection at the header area as well.

But that's just me.

xSpace wrote: Caulking, in this case, is not specifically a component of making a studio, especially in your door area. It is the difference between air,water getting into your house and not.

Ah....I thought you were talking about acoustic purposes.

The door currently has some pretty good weather stripping on all sides (pics). The bottom now also has the weight of the door itself ensuring a tight seal. As you mentioned xSpace, its the seams between the panels that worry me a bit. I don't want to take the panels apart now though - maybe I'll add clear silicone caulking from the outside? I certainly don't want moisture getting in and rotting my outer leaf! It is however a really tight gap between the panels. You can't see daylight through them.

You can see in the pics where I removed the exterior lights. I thought about keeping them somehow but didn't want to worry about electrical cable running through my added mass around the door. Plus they wouldn't be very accessible. I might see if I can find some solar powered lights to replace them.

Gotta get something covering those holes!

Thanks for looking and the input guys!

I've never really settled on how the inner ceiling should be constructed and wanted to throw some things out here;

The first thought I had was 2x4x16 studs cut to fit the span of each room (13' 3" for the control room and 9' 1" for the live room), sitting 12" on center. That's in the first pic. I'm pretty sure this is spanning 2x4s beyond their capabilities?

Second thought was laminating two 2x4x16 studs together and sitting them 16" on center like in the second pic.

The one contractor I talked to suggested blocking between the joists every 4 feet or so (pic three).

I'm pretty sure blocking is required by our local building code for floor joists so it wouldn't be a far stretch for using it like this.

I know that the closer the studs sit the more they'll transmit sound through the ceiling but I absolutely want to find a way to stay with 2x4s. But obviously they also have carry the load I'll be putting up too....

Thoughts?

The first thought I had was 2x4x16 studs cut to fit the span of each room (13' 3" for the control room and 9' 1" for the live room), sitting 12" on center. That's in the first pic. I'm pretty sure this is spanning 2x4s beyond their capabilities?

12" OC puts them really close together, and raises the resonant frequency of the ceiling, which is not good. You should be aiming for 24" OC, to get your resonance down, not up!

What kind of wood are your joists? If you are using plain old southern pine, then yes, that probably is beyond the limit. Try playing around with this fun span calculator, and see if you can get a better fit:

http://www.awc.org/calculators/span/calc

It seems to me that if you go up to 2x6, then you can easily span 9 feet even at 24"OC, and 13 feet at 16" OC.

But Brien is the guy you want to talk to about that, not me. I can plug in numbers to that calculator all day, and pretend I know what I'm talking about, but I actually don't have much of a clue when it comes to spans and stuff. Brien does.

- Stuart -

Hey Stuart, thanks for the thoughts.

I had used the span calculator but it doesn't offer special considerations such as laminating studs together. Also, the lowest live load available is 10psf but mine would be 0 since this ceiling will be inside of the outer ceiling. Even if someone needs to get into the attic space to service the HRV ducting they'll be on the outer truss not this inner ceiling, so there would never be a live load. BTW - the entrance to the attic space will be through the gable end on the exterior not through the inner ceiling.

On that note - I will probably have to beef up the existing truss. I'm currently trying to track down who designed and built this truss to get their recommendations on how to strengthen it to meet my needs.

The wood I'll be using are Spruce-Pine-Fur grade A (which I think is No. 1 on the calculator). It seems with that wood I should be fine with a 16" OC in the live room (which is actually 10' at the furthest point because of my angled walls). I'd probably still look at laminating every other joist or something like that just to give it lots of strength.

I feel at this point I might sacrifice some transmission through the ceiling in order to stay with 2x4s - especially in the control room where the dBs won't be as high. Remember, there's nothing above me but exterior.

I guess the question is how much extra span would laminated joists give me?

Hmmmm.....of course, even in the control room low frequency transmission will be a consideration. I think I need to look at transmission data again for various designs.......

Also, the lowest live load available is 10psf but mine would be 0 since this ceiling will be inside of the outer ceiling. Even if someone needs to get into the attic space to service the HRV ducting they'll be on the outer truss not this inner ceiling, so there would never be a live load.

So just subtract 10 from the dead load, and leave the live load at 10! AFAIK, that should give you pretty much the right answer. Total load is total load...

I feel at this point I might sacrifice some transmission through the ceiling in order to stay with 2x4s -

Is there a reason you need to stay with 2x4s? If you are concerned about ceiling height, you could always build your ceiling inside-out. Then you could use whatever size joist you need, pretty much.

especially in the control room where the dBs won't be as high. Remember, there's nothing above me but exterior.

Well, yeah, but your weakest link is your weakest link! It doesn't matter if it is the ceiling, the wall, the door or the window: Whichever part gives you the least isolation defines how well your entire structure isolates: Especially at low frequencies, which are non-directional by nature. If they get out, then they are out in all directions. And if they are coming in, they can come in from any direction...

- Stuart -

The ceiling in one of my rooms looks a lot like this and I was wondering the span on the 2x4's also. I'm thinking that I may put another brace under the 2x4's through the center of the room, splitting the load on those joists in half, but I'd rather not.

My first layer will either be plywood or OSB (just my personal choice). I've done this is two rooms already and it really stiffened the ceiling. Much more than drywall it seems. I am wondering if the plywood/OSB layer will add to the structural integrity of the 2x4's, or is that just wishful thinking?

Scott

Hey Scott, thanks for posting. Do you have a design or build thread going yet?

You mean you're cutting the OSB to fit in between the stud cavities, right? This would certainly provide at least some bracing between the joists and prevent them from warping, which is really good.

I am pretty sure that the blocking between studs does spread the load and therefore adds structural strength, I'd think you should be able to do that rather than adding an additional beam below the ceiling as you mentioned.

But of course, this is the very question I'm asking. Anyone have an answer?

I've done this is two rooms already and it really stiffened the ceiling.

Why would you want a stiffer ceiling? That will increase the resonant frequency, thus reducing isolation at the low end.

My first layer will either be plywood or OSB (just my personal choice).

Well, if it's just personal choice, then that's what it is! But it isn't acoustically valid reasoning. It will make the ceiling thicker and more expensive to build for the same mass, or less massive for the same cost, and with reduced acoustic isolation either way. But if you prefer it that way, then that's fine, I guess. As long as you understand what you are sacrificing, and don't mind the limitations.

... and it really stiffened the ceiling. Much more than drywall it seems.

That's why the experts here recommend drywall! Building a wall (or ceiling) with 24"OC studs and drywall brings down the resonant frequency about as much as you can without spending huge amounts of money on exotic materials, such as lead for example. Stiffening the wall by putting the studs closer together or using less dense but thicker and more rigid materials, will raise the resonant frequency of the wall assembly, thus also raising the frequency at which you get minimum isolation, and probably bringing it into an area where you don't want it.

You WANT the wall to be resilient, and you WANT density, and you WANT mass. There are good solid acoustic reasons for the recommendations made by the experts here.

Don't get me wrong: what you are doing with plywood or OSB will still work for isolation, to a certain extent: It will just be less effective, or cost more. Or both. If you don't need maximum effectiveness, and don't mind spending more money than you need to, then personal choice wins out over acoustic science!


- Stuart -

Soundman2020 wrote: Well, if it's just personal choice, then that's what it is! But it isn't acoustically valid reasoning. It will make the ceiling thicker and more expensive to build for the same mass, or less massive for the same cost, and with reduced acoustic isolation either way. But if you prefer it that way, then that's fine, I guess. As long as you understand what you are sacrificing, and don't mind the limitations.

But the reasoning here (at least for me) is to match the exterior walls, which have a layer of OSB sheathing on the outside of the studs plus the two layers of drywall that I'm adding between the studs.

Since the existing bottom chords of the truss have nothing on them right now they'll need a layer of OSB plus two layers of drywall to match the walls. Sure, three layers of drywall might be better but it wouldn't be consistent.

cómo es que?

- Greg