Understanding STC and where to apply drywall

ENIGMACODE · Oct 20, 2004

Hello Rod Gervais, Michael Jones, fitZ2, knightfly and others
(don't know what I'd do without you guys)

This thread is a continuation of understanding the STC rating of walls and where to apply drywall.

Hope you guys don't mind this new thread (the old one was getting lengthy)

If you guys have followed my dilemma here, you'll remember that I'm working in some very difficult circumstances.

Just to review some details and coming up to speed:
The ceiling problem (illustrated below), unfortunately wasn't foreseen. :mad:

The area above the music iso room is my living room.
I live ALONE, so perhaps I can fix at least some of the problem in the illustrations below. :cool:

If I were to guess at understanding Rod's Gervais's explanation as he quotes here: "The fact is that you lose big TL values when you do this inside a wall with only inches in the equation - and you gain slightly when you do it with a hallway - and the bigger the hallway the more you gain until you reach a point where you gain the actual value of both walls (enough separation to completely negate the multiple) and beyond that you gain for the additional distance of travel."

Please bear with me, it may appear as though beyond a greater distance of several feet, and in this situation, it seems as though it becomes more efficient to drywall those outer walls of an iso room. Yes? :confused:

However in terms of inches, it's best to keep things sort of 'open celled' like this: http://home.ucwphilly.rr.com/livesound/rick-combo.jpg

If I'm correct, this is all very good in a perfect world, or as in 'NEW' construction. My problem has always been working in an old 84 year old home. Frankly I don't know how I do it? As fitZ2 stated: "Man, I'm glad I'm not building this one - with stairwells, shops, garage doors, existing floors above........you must be a glutton for punishment!

I gotta get some kind of a break here (it's all just a hobby) :eek:

Rod Gervais · Oct 20, 2004

ENIGMACODE said:
However in terms of inches, it's best to keep things sort of 'open celled' like this: http://home.ucwphilly.rr.com/livesound/rick-combo.jpg

You got it - that exactly is the idea.

And if you turn it sideways - that's the idea for ceilings/floors.

please just take another look at these illustrations:

http://home.ucwphilly.rr.com/livesound/room-problem-2.jpg - rough sketch of part of the dilemma

I bet you can get to the outside bottom of the bottom door as well. And to elaborate a wee bit further........... finish those walls to within 1/4 to 3/8" of the inside face of the exterior sheathing (or concrete if that's what it is) and caulk those edges.

http://home.ucwphilly.rr.com/livesound/pict-10a.jpg < overview to back wall

against the masonry wall you're fine - at the outside wall drill some of those 6" holes through that drywall that shouldn't be there that is drywall below the insulation isn't it?)

http://home.ucwphilly.rr.com/livesound/pict-3a.jpg < wider view of back hallway [/quote]

yes

http://home.ucwphilly.rr.com/livesound/pict-2a.jpg < closer hallway shot - please check this one out

yes again

http://home.ucwphilly.rr.com/livesound/pict-4a.jpg < wide view of under steps

cut back the stair threads so you gain more room there - that appears to be a single wall - and if you can you should either double it up (prefered) or add rc to the inside - but you want to be able to get 2 layers of DW on the stair side and make certain the stairs never touch the drywall.

http://home.ucwphilly.rr.com/livesound/pict-5a.jpg < closer view of under steps

see comments above

http://home.ucwphilly.rr.com/livesound/pict-7a.jpg < ceiling problem

yup......... you're right - that's a problem........

http://home.ucwphilly.rr.com/livesound/pict-9a.jpg < a suggested solution to the ceiling problem

yup - that's a solution.

Rod

fitZ2 · Oct 20, 2004

cut back the stair threads so you gain more room there - that appears to be a single wall - and if you can you should either double it up (prefered) or add rc to the inside - but you want to be able to get 2 layers of DW on the stair side and make certain the stairs never touch the drywall.

That is exactly what I wanted to hear. The "pro's" verification. I wasn't sure
when it comes to another space like the stairs. But I "thought" it should be decoupled via RC on the STUDIO side. I would have suggested another wall, but space being a premium, and the ceiling is already framed, and.....and...hahahaha! Its those connections at the ends of the wall that had me really stumped though. Thanks Rod.

I gotta get some kind of a break here (it's all just a hobby)

BREAK

Are you kidding. Get back to work you SLOUCH!

And while your at it, fix me a drink so I can relax while I watch you punish yourself some more on that ceiling. And put your back into matie! I wanna see this done by next Monday!!

fitZ

knightfly · Oct 20, 2004

Michael, on rare occasions I've caught Rod in minor "mind farts", and vice-versa (more often the vice-versa part :=) - In this case though, I not only agree with what he said it's pointless to try and add anything. I think you're as "lined out" as possible here, so I'm gonna try to get at least 4 hours of shut-eye before the alarm pisses me off... Steve

ENIGMACODE · Oct 21, 2004

Thank you Thank you - just some further clarification

Hey Hey - Thank you! I needed this bit of levity

from fitZ2:

"BREAK Are you kidding. Get back to work you SLOUCH!
And while your at it, fix me a drink so I can relax
while I watch you punish yourself some more on that ceiling.
And put your back into matie! I wanna see this done by next Monday!!"

Hey fit - you also said:
"But I "thought" it should be 'decoupled' via RC on the STUDIO side"
Well I'm sure you noticed that I took great pain in separating all
old structures from direct contact with the new room structure here:
http://home.ucwphilly.rr.com/livesound/pict-5a.jpg
I guess you're saying that 'in addition' to this, I should look into
installing RC when I get ready to install rock opposite the stairs
on the studio wall side? yes?

And knightfly you mentioned:
"I not only agree with what he said it's pointless to try
add anything. I think you're as "lined out" as possible here"
knightfly where you referring to this photo where I unfortunately
already rocked the garage door opening on the back wall?
I first contemplated adding 703 to that new rocked wall to get that
STC 57 'open cell' here:http://home.ucwphilly.rr.com/livesound/rick-combo.jpg
Hey Steve - hope you get some sleep! :cool:

And Rod suggested drilling 5" holes with a hole saw in that new rock for 'venting'. But actually that NEW framed wall in front of it, is NOT fastened in place yet. Soooo it's easier to just remove that drywall. And after that I'd like to add some open faced R11 over the faced R11 that's in that wall now. Then proceed in fastening the new sub wall back in place. Sound like a good idea?
Here: http://home.ucwphilly.rr.com/livesound/pict-10a.jpg

Rod Gervais you stated:
http://home.ucwphilly.rr.com/livesound/room-problem-2.jpg - rough sketch of part of the dilemma -
"I bet you can get to the outside bottom of the bottom door as well.
And to elaborate a wee bit further........... finish those walls to
within 1/4 to 3/8" of the inside face of the exterior sheathing
(or concrete if that's what it is) and caulk those edges."
I take it that you were referring to proper installation of drywall
on those exterior walls yes?
Here: http://home.ucwphilly.rr.com/livesound/pict-2a.jpg

But until I get some clarification (I'm a little stunod 'slow'),
I'll have to try to understand your statement further... I just
assumed that I'd follow your original instructions and bring the drywall
back about 1/4" from the edge of the framing (exterior side). Then caulk all those meeting places (where the rock is attached at the edges of the framing exterior side)?? I'm really sorry Rod. I'll get this yet! I appreciate all help! We'll talk about this further...

Talk soon ... :cool:

Best Regards
Michael Fraticelli
ROCKON@ucwphilly.rr.com

Rod Gervais · Oct 21, 2004

ENIGMACODE said:
And Rod suggested drilling 5" holes with a hole saw in that new rock for 'venting'. But actually that NEW framed wall in front of it, is NOT fastened in place yet. Soooo it's easier to just remove that drywall. And after that I'd like to add some open faced R11 over the faced R11 that's in that wall now. Then proceed in fastening the new sub wall back in place. Sound like a good idea?

Sure Does

I take it that you were referring to proper installation of drywall
on those exterior walls yes?

Ok - here's a detail for exterior walls - but i was also refering to that lowest left hand door - you need to get to the outside bottom of it......

knightfly · Oct 22, 2004

I'm kinda getting lost here; do you or do you NOT have a floor plan of this project? Because I'm at a loss as to where Rod's detail should go; for one thing, I'm trying to figure out why half of that drawing isn't a triple leaf; Also, in

http://home.ucwphilly.rr.com/livesound/pict-10a.jpg

is the hallway referred to on the left, the same hallway that ends at the outside door?

If that's the case, I would also rock both sides of that frame (RC one side) - your outside door looks to me like that light over it will negate much of the door's isolation anyway, plus if your studio's just on the other side of that wall you should STILL have a 2-leaf partition between the studio and outside when the door is open.

Rod, why is the upper right half of your last drawing NOT a triple leaf, or is there something I've missed that makes it necessary?

Michael, do we get a floor plan? Later... Steve

Rod Gervais · Oct 22, 2004

knightfly said:
Rod, why is the upper right half of your last drawing NOT a triple leaf, or is there something I've missed that makes it necessary?

Steve,

From the topmost of the drawing.........

Exterior sheathing - exterior 2x4 wall framing - 1" air space - interior 2x4 wall wall framing - 2 layers of drywall.

the middle is just air - I would not put a third leaf in my friend ..........

Wall on left that turns down the page is - (left side) 2 layers of drywall - 1/2 RC1 - 2x4 wall - 2 layers of drywall - (I agree with you on the RC)

The left 2 layers are on the corridor side of the wall - (the door to the outside world) and should continue to within 1/4 - 3/8" of the exterior sheathing (fitting around the plates with the same clearences) and then should be caulked.

This will stop the short circuit that exists at that wall end.

Sorry that the sketch caused confusion.

Rod

ENIGMACODE · Oct 22, 2004

Hello Rod, knightfly, and fitX2 (another rough room layout)

Hey Guys ...

Thanx for keeping this thread alive

Yes well I was trying to provide enough photos and rough drawings so that you guys could get a clearer picture as to what I dealing with here :cool:

I'm sure you're all well aware by now of the tightness and difficult going in regard to what contractors call this 'old kind of work' it's really tough :eek:

(as opposed to NEW construction)

But challanging at the same time

kinghtfly asked:
"is the hallway referred to on the left, the same hallway that ends at the outside door?"

Yes > http://home.ucwphilly.rr.com/livesound/pict-3a.jpg
Try this too > http://locationstudio.net/room-1.jpg

kinghtfly mentioned:
"your outside door looks to me like that light over it will negate much of the door's isolation"

If you mean the 'daylight' via a window over the door, that's correct.

But I was thinking it would be a lot easier to deal with that AFTER I complete the music room and see how much bleeds through it. I can more easily just block it off with Plywood and R11. (make sense?)

And in regard to Rod's sketch and comment:
http://www.homerecording.com/bbs/attachment.php?attachmentid=11200
"but i was also refering to that lowest left hand door - you need to get to the outside bottom of it......"

Rod - you were referring to the 'smaller' door at the bottom of the basement steps on the landing correct?

Well, I should take some close up shots of the door opening so that you can get a better view of what's going on so far.... ok?

I'll need to understand your sketch a bit better in regard to that .... :confused:

Back in a few days .... :rolleyes:

Have a nice weekend guys

Best Regards
Michael Fraticelli
ROCKON@ucwphilly.rr.com

Rod Gervais · Oct 22, 2004

Mike,

The whole intention of my sketch above was to deal with that exterior door and the issues related to that.

I must be getting pretty old if I am having this big a problem getting my message across.......... lol

I guess I'll do a different detail that shows that outside door.........

Rod

knightfly · Oct 22, 2004

Hey Rod; I didn't consider that the middle section on that drawing was just air, guess it's MY mindfart this time (duh...) I knew you wouldn't "do a triple", but for some reason (like 12-hr shifts, 4 hr. sleep, bad cold) I just couldn't see it -

Hey, my normal situation (and yours, probably moreso) reminded me of a very bad joke; do you know why candles don't work for lazy people? Because "there's no wick for the rested"...

OK, I'm all better now (said with fingers crossed)

Michael, whenever possible it's good to completely thrash this stuff out until NO ONE has any doubts whatever about the plan; here's a painful but classic example of WHY this is so important - I almost cried when I had to inform this guy why his construction didn't work -

http://www.recording.org/modules.php?name=Forums&file=viewtopic&t=22469

Sooo, Michael, any time we seem overly verbose, trust me it's less painful that way... Steve

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