Looking for some insight regarding my garage build...

How thick should my walls be, should I float my floors (and if so, how), why is two leaf mass-air-mass design important, etc.

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The Dread
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Location: Chicago, USA

Re: Looking for some insight regarding my garage build...

Post by The Dread »

I'm baaaaaacckkkk...
What a month, stupid winter....but I am getting a little better with Sketchup, which is a bonus.

So, I'm finally getting back to my L/R build and just realized that I have an obvious issue that exists at a section of my outer leaf, which obviously went undetected till now.

In the attached picture, with the red and green lines, you are looking at two exterior walls and the ceiling to my L/R (outer leaf). On the opposite side of the L/R ceiling (my C/R), I built knee walls about 3' inward, away from the exterior walls of the building (from the red line and to its right). My issue is that the mass of the outer leaf (from the left of the red line to the green) is only 3/4" plywood, which clearly lacks the extra mass of the 1/4" rubber underlay & 3/4 finish planks in the C/R.

Can I simply apply mass at these locations, underneath the subfloor, about 4' out, and then just seal them really well, for example...I'd rather not have to beef up the entire length of each bay, like I did the walls, but it seems a patch isn't quite the same as having the entire mass on the same plane.

Any recommendations? More questions coming soon. Thanks!

Cheers! :mrgreen:
-If you're in control, you're not going fast enough.-
Gregwor
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Re: Looking for some insight regarding my garage build...

Post by Gregwor »

In the attached picture, with the red and green lines, you are looking at two exterior walls and the ceiling to my L/R (outer leaf). On the opposite side of the L/R ceiling (my C/R), I built knee walls about 3' inward, away from the exterior walls of the building (from the red line and to its right). My issue is that the mass of the outer leaf (from the left of the red line to the green) is only 3/4" plywood, which clearly lacks the extra mass of the 1/4" rubber underlay & 3/4 finish planks in the C/R.

Can I simply apply mass at these locations, underneath the subfloor, about 4' out, and then just seal them really well, for example...I'd rather not have to beef up the entire length of each bay, like I did the walls, but it seems a patch isn't quite the same as having the entire mass on the same plane.
I don't fully follow what you're saying but I hope this answer will clear up your question -->

Make sure everywhere has the needed amount of surface density. If only part of your subfloor is lacking the mass, then all you have to do is add the mass where it is lacking.

Greg
It appears that you've made the mistake most people do. You started building without consulting this forum.
The Dread
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Location: Chicago, USA

Re: Looking for some insight regarding my garage build...

Post by The Dread »

Hey Greg,

Yes, I certainly over complicated the question.

Basically, there is a section of my LR ceiling/outer leaf that is only 3/4" ply, rather than 1-3/4", because the extra inch of attic flooring terminates about 3' from the exterior walls/outer leaf, as there is a knee wall in the attic...so I visualized that beefing it up from under that shallow area in my L/R wouldn't be ideal, because maybe the new beef material (being on a different material plane?) would only serve as a 'patch' but not a proper application of mass...again, over complicating, if any of that makes sense.
-If you're in control, you're not going fast enough.-
The Dread
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Joined: Mon Jul 16, 2012 2:13 am
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Re: Looking for some insight regarding my garage build...

Post by The Dread »

...also, I am getting to the point where I can start building my inner leaf walls, and I have been scratching my head with all of the different approaches I can take to install the ceiling.

Luckily for me, it seems, my stud bays are free and clear of conduit, ducting, braces, etc., which leads me to believe that I am afforded a couple different installation methods for this application.

...so, I am looking to use my outer leaf's 11" ceiling stud bays to house the inner leaf ceiling joists, which I've gathered is a common approach that helps to avoid losing critical ceiling height, however, I haven't seen one single example/picture that portrays the way I plan to do it, which is to simply build the inner leaf walls and add the ceiling joists above them, in between the existing ceiling joists & obviously decoupled entirely; besides not being able to install a rim board around the inner leaf ceiling joists, why wouldn't I simply notch them at the ends and straight-nail and toe-nail them in through the upper sill plates?

The main issue that seems problematic to me is that the notches decrease the joists load carrying ability, which doesn't seem significant with the fairly small span I have to run and the amount of space I have in the bay, which could allow for notched 2x10"s (or 2x8"s), which seems adequate to me. I realize that the lack of rim boards aren't ideal, but I can't really believe that to be the deal breaker with my approach.

...I do enjoy the inside-out ceiling look though, with the joists exposed (under the drywall look)...which would actually match my control room's exposed collar tie look.
-If you're in control, you're not going fast enough.-
Soundman2020
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Re: Looking for some insight regarding my garage build...

Post by Soundman2020 »

so, I am looking to use my outer leaf's 11" ceiling stud bays to house the inner leaf ceiling joists, which I've gathered is a common approach that helps to avoid losing critical ceiling height,
It's one way, yes, but as you already discovered, it's complicated, hard to get right, and you run the risk of inadvertently creating flanking paths that you can't even see...

On the other hand, doing an "inside out" ceiling will get you greater acoustic ceiling height, better isolation, and is easier to do right, with nothing hidden and less chance of messing it up... :)

...I do enjoy the inside-out ceiling look though, with the joists exposed (under the drywall look)...which would actually match my control room's exposed collar tie look.
Yup! :thu:


- Stuart -
The Dread
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Re: Looking for some insight regarding my garage build...

Post by The Dread »

Hey guys, happy Friday!

I've been reading Rod's book, and have stumbled upon a statement that is conflicting with my thought process; regarding Door Frame Construction, he says, "I'll let you know right now that this is one place I don't worry about maintaining the separation of wall assemblies with the frames, even when using totally separated assemblies...tests have proven that a through jamb does not effectively lessen the total isolation value of a wall assembly to any great degree. So don't worry about any minuscule amount of isolation you may lose."

For me, this statement has serious implications that assuredly conflict with what is routinely preached here at J.Sayers (i.e. a single nail creating a flanking path, for example). Obviously, it gives us noobs a loud warning to make us acknowledge the severity of the situation, and to avoid it when possible, but as a result, I've never even considered tying the two leaves together at the door frame, which certainly would be an ideal option for me, (assuming that it won't drastically compromise my isolation)...I do have a massive studio door w/ magnets, beveled lowering hinges, etc., which hopefully will provide the isolation I need without the need for an extra door. Any thoughts, advice, or recommendations here?

Secondly, I'm close to buttoning up my outer leaf entirely, and I have some rough ideas about my HVAC, lighting, etc., but I can't locate any information that illustrates the best way/location to bring in/run my electrical service (conduit, boxes, etc.)...similar to the 'no door in the corner rule,' would it be ideal for me to route my main conduit service feed through both leaves, somewhere in the middle of whichever wall I choose to penetrate?...or does it matter little, as long as I seal it up heavy and tight?

Thanks in advance, I hope you're all doing well! :D
-If you're in control, you're not going fast enough.-
Soundman2020
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Re: Looking for some insight regarding my garage build...

Post by Soundman2020 »

I have never tested Rod's "single frame for two doors" technique (I always do dual frames, one for each leaf), but it also raised my eyebrows when I first saw that, years ago. Then I got to thinking about, and the probable explanation here, is "mass and rigidity". The framing around doors has to be very substantial in any case (one frame or two frames: Still needs to be massive), just to handle the huge weight of a typical studio door, and even more so for Rod's "superdoor". The frame has to be able to keep the door perfectly vertical at all times: open, closed, or anywhere in between... without sagging, twisting, bending, or otherwise distorting in any way. Normally you have at least studs on each side of the door, plus additional noggins, an over-sized header, and tie-down bolts in the sole plate, close to all that. So there's a LARGE amount of mass, just in the rough framing. Plus the mass of the door frame itself, plus the mass of the doors, which normally have higher surface density than the rest of the wall, to help compensate for the lack of insulation in the cavity, and the simple fact that they are doors.

Both the doors themselves and the frames they hang on are also very rigid, in addition to being very massive. So those are not going to move much. Airborne sound isn't going to have a huge effect on them. Tying them together isn't going to reduce the TL by anything substantial either.

That's my theory, but I don't have any data to back it up. And as I said, I haven't ever tried a "single frame for both leaves" approach, so I can't say much about how effective it is, or isn't.
but I can't locate any information that illustrates the best way/location to bring in/run my electrical service (conduit, boxes, etc.)...
This is the way I normally suggest for doing that: One single power feed into the room, then distribute it from there. That normally means that you'll need a sub panel inside the room, with breakers for your individual circuits, and possibly also an RCCB or ELCB, if required by code (or just for being smart). All of the actual wiring inside the room is done with surface-mount raceways and fixtures, such as these:

ttp://www.calcentron.com/Pages/fram-trak/fram ... aceway.htm
http://www.export.legrand.com/EN/dlp-wa ... ng_95.html
https://www.electriduct.com/Cable-Raceways.html

For the actual cable penetration, here's how I do it when I need high isolation for the room:
Conduit-isolation-0-SML-ENH.png
Conduit-isolation-1-SML-ENH.png
Conduit-isolation-2-SML-ENH.png
Conduit-isolation-3-SML-ENH.png
In words: Use thick PVC or metal conduit, bent in a gentle curve, one in each leaf, well sealed into its penetration hole, and perhaps with a putty pack around the penetration, to beef up the mass a bit. Line up the two pieces of conduit so they face each other but with a gap between them, then wrap that gap with a sheet of very flexible rubber, attached to the conduit with glue and zip-ties. Pull the wiring through in the normal manner. Stuff insulation down the end of the conduit where it comes through the wall, pushed in as far as you can get it, then cap the end of the conduit with abundant caulk.

If you don't need very high isolation, then you can probably skip the "gap and rubber" part.

However, do check your local electrical code to see if that is allowed. Where I live, it is compulsory to use conduit in walls for power feeds, and flexible couplings are allowed, but there might be some quirks in your local code that messes up this plan.

The conduit also just makes it so much easier in the future, if you need to replace the wiring or run additional wiring. You can pry off the caulk, fish out the insulation plug, then the conduit is open for business again.

There's probably other techniques too, but that's what I do. Of course, if you don't have a slab yet and will pour one, then just embed the conduit in the concrete!

One word to the wise, here: make your bends GENTLE! Don't get tight elbows, or you'll never be able to pull heavy wiring through. Use wide radius curves...

- Stuart -
The Dread
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Re: Looking for some insight regarding my garage build...

Post by The Dread »

Hey Stuart, thanks for the advice/references!

I still have very much to do, but am feeling really good about where I currently stand, and I can't give you (and Greg) enough praise for the time you have given me, to help guide me through my build. 8)
I have never tested Rod's "single frame for two doors" technique (I always do dual frames, one for each leaf), but it also raised my eyebrows when I first saw that, years ago.
Damn, I was hoping you'd say something like, "yes, that framing method has been overly tested, tried and true, and because you have a high quality, massive studio door, of course you should go about it that way, so you don't have to buy/make another inner leaf door." Hahaha, in a perfect world, pigeons also sh*t gold.
Both the doors themselves and the frames they hang on are also very rigid, in addition to being very massive. So those are not going to move much. Airborne sound isn't going to have a huge effect on them. Tying them together isn't going to reduce the TL by anything substantial either.
I have visualized this to be the case, but the obvious issue with flanking (a term I understand, but know little in regard of what to expect in the form of a measurement) has encouraged me to utilize a truly decoupled system; I now, with the above statement in mind, think I will in fact opt for the single door/tied leaf construction at the frame...and if it (bad isolation) becomes a nuisance in the future, it wouldn't be entirely frustrating to add an inner leaf door after the fact. :thu:

-Electric/Conduit-
This is the way I normally suggest for doing that: One single power feed into the room, then distribute it from there. That normally means that you'll need a sub panel inside the room, with breakers for your individual circuits, and possibly also an RCCB or ELCB, if required by code (or just for being smart). All of the actual wiring inside the room is done with surface-mount raceways and fixtures, such as these:

ttp://www.calcentron.com/Pages/fram-tra ... aceway.htm
http://www.export.legrand.com/EN/dlp-wa ... ng_95.html
https://www.electriduct.com/Cable-Raceways.html
I'm going to have to get crafty here, as my garage breaker box is in my LR outer leaf wall (between leaves & in the air cavity), so I'll probably need to install a small door for access to it, unfortunately. :evil: ...but great, I recognize the electrical approach illustrated and will be getting to it soon. :mrgreen:

...Use thick PVC or metal conduit, bent in a gentle curve, one in each leaf, well sealed into its penetration hole, and perhaps with a putty pack around the penetration, to beef up the mass a bit. Line up the two pieces of conduit so they face each other but with a gap between them, then wrap that gap with a sheet of very flexible rubber, attached to the conduit with glue and zip-ties. Pull the wiring through in the normal manner. Stuff insulation down the end of the conduit where it comes through the wall, pushed in as far as you can get it, then cap the end of the conduit with abundant caulk.
Nice, this is actually what I was thinking I'd end up doing; my 'acoustical' intuition is finally developing. What a great feeling.
One word to the wise, here: make your bends GENTLE! Don't get tight elbows, or you'll never be able to pull heavy wiring through. Use wide radius curves.
Oh yea, Stuart, I've played the ol' tight bend wire pull game before, and yes, it sucks bad. Noted.

You're the best, my friend, many thanks! Enjoy the weekend! :inn:
-If you're in control, you're not going fast enough.-
The Dread
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Joined: Mon Jul 16, 2012 2:13 am
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Re: Looking for some insight regarding my garage build...

Post by The Dread »

Happy Sunday, long lost friends, it’s been awhile, I hope you’re all doing as well as can be, in this crazy Covid world!

Anyhow, I’m looking to get back to it. I have my outer leaf air tight, have designed a system for my air needs, and am about to get to laying out the conduit for the electric/audio. I’m finally beginning to feel good about this room.

So, I am still a little lost on the inside-out ceiling. I thought there was a link in this thread, but I can’t seem to find it.
Soundman2020 wrote:
so, I am looking to use my outer leaf's 11" ceiling stud bays to house the inner leaf ceiling joists, which I've gathered is a common approach that helps to avoid losing critical ceiling height,
It's one way, yes, but as you already discovered, it's complicated, hard to get right, and you run the risk of inadvertently creating flanking paths that you can't even see...

On the other hand, doing an "inside out" ceiling will get you greater acoustic ceiling height, better isolation, and is easier to do right, with nothing hidden and less chance of messing it up... :)

...I do enjoy the inside-out ceiling look though, with the joists exposed (under the drywall look)...which would actually match my control room's exposed collar tie look.
Yup! :thu:

- Stuart -
If there is a solid picture process of this approach in action, can you please help me find it?

Expanding on this, if I do the inside-out ceiling, is it common to pink fluffyglass the Live Room INTERIOR ceiling bays and burlap, or rock wool and burlap?

I’m so close, it’s really starting to eat at me, haha!

As always, thanks in advance! I hope you’re all well. Cheers!
-If you're in control, you're not going fast enough.-
The Dread
Posts: 51
Joined: Mon Jul 16, 2012 2:13 am
Location: Chicago, USA

Re: Looking for some insight regarding my garage build...

Post by The Dread »

Tight like tiger.
-If you're in control, you're not going fast enough.-
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