John Sayers' Recording Studio Design Forum Archive

Steve, this is GREAT! Just a few questions now:

I already have 1/2" 60 durometer rubber strips that I cut for floating the floor in the iso booth (I have left overs). Even though you've iilustrated 1/4" for the neoprene, is there any good reason NOT to use 1/2" since I already have it?

Furthermore, do these strips get glued at 1, 2 or 4 ft. intervals along the length of the new wall cap (or some other interval)?

Additionally, should I caulk the hell outta the spaces BETWEEN those neoprene strips or fill them with soundboard/homasote pieces (or Thermafiber?) and THEN caulk?

Somewhere I read here about a free version of drawing software for the Mac...anyone have a link/info??

Finally, looking at your drawing, it shows RC on the INside wall of what would be the iso booth. My plan was to put the RC on the inside wall of the control room wall, which is the wall that is already up (the wall on the right in your drawing). Is it recommended to use the RC in the ISO booth/drum room or inside the control room?

Steve, you rock!

dean

The 1/2" neoprene should be fine - you would still compress it horizontally by c-clamping the second runner/neoprene/wall cap/neoprene/first runner all together horizontally; you could compress it more since it's a percentage of thickness we're after here - neoprene is a spring, and springs are NOT springs at either end of their travel.

For that same reason, you should NOT make the top piece of neoprene a tight fit - it is mainly there for insurance, so that if the joist sags you won't have hard contact. I would leave maybe 1/8" gap across the top piece of neoprene for that reason.

Forgot to mention - the neoprene strips should be done every 3-4 feet, their main purpose is to keep the wall from shifting while still avoiding hard contact. Most of that function will be accomplished by the stiffness of the wall frame itself, although it's conceivable that caulking may exert some pressure - every 3-4 feet should take care of that too.

"Additionally, should I caulk the hell outta the spaces BETWEEN those neoprene strips or fill them with soundboard/homasote pieces (or Thermafiber?) and THEN caulk?" -

No need. Everything behind the wallboard is only there to support the wallboard. The wallboard layers, and the caulking where they meet, are your ONLY hermetic seal. Anything else can be stuffed with insulation if there's room. The ONLY purpose for the neoprene is to prevent flanking between framing members, and consequentially into the rest of the house as I described in the text on the drawing.

"looking at your drawing, it shows RC on the INside wall of what would be the iso booth. My plan was to put the RC on the inside wall of the control room wall, which is the wall that is already up (the wall on the right in your drawing). Is it recommended to use the RC in the ISO booth/drum room or inside the control room? " -

Normally it would make absolutely ZERO difference which side has the RC, as long as it's only ONE side - however, since one of your frames is already in hard contact with the rest of the framing, putting the RC on the CR side makes more sense. That way, that hard frame has less chance of being vibrated by the CR sounds, so less flanking will occur.

"Somewhere I read here about a free version of drawing software for the Mac...anyone have a link/info?? " -

See if any of these helps -

http://www.johnlsayers.com/phpBB2/viewt ... awing#5924

"Steve, you rock!" - (Spoken in biggest, deepest voice, smacking of blatant self-promotion) "DAMN STRAIGHT..."

If I understand this correctly, then, the neoprene rubber on TOP of the new cap should NOT touch the existing ceiling runners? i.e. leave 1/8" gap and don't worry about caulking the rest of the gaps along the length of the cap?


Ok. So, now that I've got this figured out, back to my original question:

In what order should I put this construction together? My thinking is this:

***Build the runners/cap(with neoprene) using clamps as suggested, THEN mount the entire thing to the existing ceiling, propping it up with 2x4 studs (or similar) just so I can get it screwed to the existing runners (screwing in just the two surrounding runners and NOT the cap?).

***Build the new wall TO that new runner/cap (and on top of the floated floor).

***Put up drywall on wall, then ceiling, wall, then ceiling, with caulk after each successive layer.

Does this make sense? (sorry, I'm a novice as you can tell).

One more question for you:
Wondering if a single layer of soundboard screwed to the joists and between the runners would help isolation on ceiling (cut in 9.5" wide strips to fit between the runners to cover the insulation, then caulked to fill the gaps). It's half inch soundboard, so there would be a gap between it and the RC1 which would then get mounted HOW??--ALONG the runners or ACROSS the runners? [See picture#1 for reference]

"If I understand this correctly, then, the neoprene rubber on TOP of the new cap should NOT touch the existing ceiling runners?" -

The new wall frame cap should be TRAPPED BETWEEN two runners as I've drawn, padded with neoprene - what I'm calling runners are the flat 2x4's you've nailed across the bottoms of the ceiling joists, which are the "on edge" framing members that your subfloor is nailed to the tops of. The cap of the new wall frame should NOT be UNDER these runners, but sandwiched BETWEEN them with the neoprene keeping it from hard contact with ANYTHING.

" i.e. leave 1/8" gap and don't worry about caulking the rest of the gaps along the length of the cap? " -

That's right. The only place SEALING is important is corners/seams where drywall meets drywall. Everything else only exists to hold up the drywall. (Kind of like everybody else in the band is only there to make Kenny G sound good...)

Ok. So, now that I've got this figured out, back to my original question:

In what order should I put this construction together? My thinking is this:

***Build the runners/cap(with neoprene) using clamps as suggested, THEN mount the entire thing to the existing ceiling, propping it up with 2x4 studs (or similar) just so I can get it screwed to the existing runners (screwing in just the two surrounding runners and NOT the cap?).

***Build the new wall TO that new runner/cap (and on top of the floated floor). " -

"***Put up drywall on wall, then ceiling, wall, then ceiling, with caulk after each successive layer. " -

"Does this make sense? (sorry, I'm a novice as you can tell). " -

Doing it that way would be possible, but pretty tricky to get right. Also, alternating layers is good for wall to wall intersections, but the object in this case is to suspend the ceiling leaf (all layers of it) inside the wall leaf (all layers of it) so that the RC can maintain the flexible hanger function and allow the ceiling to float (semi)free of the walls (but still SEALED to them with caulk) - BTW, this is one area where you DEFINITELY need to find REAL acoustic-rated caulk - these joints MUST stay flexible and SEALED, or your isolation is history. Look closer at the drawing - I drew it EXACTLY as it should be built. (Other than putting the RC on the OTHER, HARD contact wall frame)

I'm going to assume (your pix don't show for sure) that the floor area in your iso booth is SMALLER than the area of your (to be added) second wall - if not, you could build the entire wall frame on the floor, then stand it up and fasten it in place.

With less space to work with, it gets more fun What you will need to do is measure very carefully so you know exactly what TOTAL height your frame needs to be, allowing 1/2" for the neoprene across the top and the 1/8" gap between the top of the top pieces of neoprene and the existing joists - note that the neoprene top spacer will be under every other joist (if your joists are on 16" centers, you can go every third one) Your side pieces of neoprene will also be directly under a joist - all three pieces of neoprene should line up under a joist. It doesn't matter WHICH side of the TOP piece of neoprene you glue - since it won't be a tight fit, either the top can be glued to the joist or the bottom can be glued to the cap of your wall frame. It would probably be easier to glue to the underside of the joist, and keep that piece shorter than the width of the frame cap. That way it won't interfere with placement of the SIDE pieces of neoprene, which ARE fairly critical.

Once you are SURE what all the measurements need to be for your wall frame (be sure to include top and bottom plates/caps in the total height PLUS the neoprene and air space, subtracting those from the total height between floor and ceiling joist to get actual stud length - if your floor or ceiling joists aren't even, you'll need to adjust overall dimensions so that NONE of the ceiling joists contact the top plate.) -

Anyway, once you're sure of dimensions, you can cut all the framing pieces and mark any that are unique so you know where they go - Also mark one side of each stud's location on the plate and cap, with an X next to that mark - this shows which side of the mark the stud goes on, and the LINE is the edge of the stud. Like this lX (pretend this line of text is the cap or plate)

Now, temporarily fasten a 2x4 horizontally across all the studs in your existing wall frame - fasten this LEVEL, and about 6-7 inches above the floor, on the side of the existing frame that will be toward the NEW wall frame. This temporary 2x4 mounts to the existing frame on edge - then, fasten a second TEMPORARY 2x4 laid flat on top of this one, to make a 3-1/2" wide shelf near the bottom of the existing wall.

Use one stud as a measuring tool, put one end of it up against your new TEMPORARY "shelf" , and the other end goes up diagonally across the room to the OPPOSITE side wall - if that wall is still only framed (no panels yet) put ANOTHER temporary 2x4 LEVEL across the studs so that each stud you lay across this "bridge" will stay aligned with the REST of the studs til you've finished nailing your new wall frame together. You will be assembling your wall frame in mid-air, so you can get at both the bottom of the bottom plate to nail through into the studs, and also get to the TOP of the TOP plate, so you can do the top end of the frame after the studs are nailed to the bottom plate.

All this seems like a pain, but it will work - otherwise, you'll need to learn how to "toenail" without letting the framing member slip around sideways, and that's not always easy even for a pro.

Next, you'll put your studs on the bottom plate (the one resting on your low shelf) one at a time (starting with the one furthest from the door) and nail them with two 16d nails through the bottom plate and into the stud, making sure you're not too close to the edge of either the plate or the stud. 1/2" is enough, provided you aim your nails so they get progressively FURTHER from the edges of the wood as they go in.

Once all studs are nailed at the bottom plate, you can put a temporary 2x4 across the UNDERSIDE of the studs, near the tops, and parallel to the bottom plate - this will keep all the studs from trying to sag individually til you get the top plate nailed on.

Before you start your wall, you can put up the runner closest to the existing wall, and glue pieces of neoprene to it coincident with the chosen joist locations, so you can eventually tip up your wall frame until it hits the neoprene stops. If your existing runners are too close to where the new wall goes, there won't be room enough to tip up the wall frame without hitting them - you may have to slide the bottom of the wall frame AWAY from the existing wall far enough to allow the top to get past the runner if that's the case.

Once you have the frame built, you can lift it off the "shelf" and set it on the floor, with the far (upper) end resting against the far wall. Remove the temporary shelf and tip up the wall frame. You can hold the frame up against the neoprene stops with a couple of C clamps til you get the bottom plate positioned so that the studs are plumb (like level, only vertical) -

After the wall is trued, you can fasten the bottom plate to your floated floor, making sure you don't use fasteners that are long enough to "short out" your floated floor - then you can glue one side of your inside neoprene pad to the top plate (in line with the other two) - then, place the new runner up against the neoprene pads (all of them) clamp them tight enough to squeeze the neoprene noticeably, and fasten the runner in place, (finally) trapping the top plate of the new wall between two padded runners.

Have a beer - I'm thirsty just THINKING about this...

"One more question for you:
Wondering if a single layer of soundboard screwed to the joists and between the runners would help isolation on ceiling (cut in 9.5" wide strips to fit between the runners to cover the insulation, then caulked to fill the gaps). It's half inch soundboard, so there would be a gap between it and the RC1 which would then get mounted HOW??--ALONG the runners or ACROSS the runners? [See picture#1 for reference]" -

This would be a BAD idea. Re-read my comments on the last drawing about ONLY two MASSES between any two areas to be isolated from each other.

I'm ready for a break - if this doesn't make sense to you, let me know and I'll draw another diagram... Steve

That is a lot of info to absorb...give me some time.

However, one question comes to mind immediately regarding the soundboard on the ceiling...I see that idea as ONE mass = ceiling joists+runners filled with Thermafiber and covered with soundboard. Kind of like a wall but horizontal. The second mass will be the RC1+drywall(x2) I understand that ideally, there should be some layer ABOVE the insulation and not below (i.e. in between the leaves).

My problem is that there are some small gaps where I've installed the insulation and caulking is impractical, for there is nothing for the caulk to "grab" to. Maybe my insulating technique is lacking and I'm looking for a way to seal it up before the RC/drywall leaf goes up. Should I use the Try-Ply across the runners before mounting the RC1?

I've done nothing with the suspended ceiling and am using it as is. All the runners you see were already there. I just took down the existing tiles/light fixtures to insulate.

"Have a beer - I'm thirsty just THINKING about this... "

mmm...I THINK I'LL HAVE A SHINERBOCK!!!!!!!!!

Scrolling back to get to the forum Index produced this double post! So sorry!

WHAT double post?

Thermafiber is considered the same as AIR, so you'd have floor, air, soundboard, air, sheet rock. Triple leaf. Trust me on this, don't put the sound board where you stated.

Any loose areas you need insulation, just stuff pieces in there. It isn't hermetically sealed or it wouldn't be insulation, plus the main function of insulation between two mass leaves is to break up currents and further reduce the sound that makes it to the "other side" - the ONLY surfaces that need to be hermetically sealed are the wallboard inside your studio, and the underside of your subfloor. Two, not one nor three, centers of mass (that you can NOT blow through no matter how hard you try) separated by ONE air space, hermetically sealed. The more mass in each leaf, the better. The wider air space between them, the better. Differently built leaves are better. Resilient mounting on ONE leaf is better, but not necessary with separate frames. Yours is an exception, because the one frame is hard coupled so needs RC.

Anything else is just spitting in the wind... Steve

Ok, so where is my double leaf for the ceiling? When I look up into the rafters I can see the subfloor from the second story. Then the 16" vertical joists, then the suspended ceiling joists which are those more visible in my pics. There is NO insulation (other than what I've added) between the 2nd floor subfloor and the suspended ceiling in my space.

So=Subfloor + air (lots of it) + insulation + RC1 + 2 layers of drywall.

That looks like one mass to me. Are you saying this will be sufficient to stop noise from above? Currently I can hear when someone walks across the floor upstairs, and all I have is the Thermafiber up now. Will adding two layers of 5/8" drywall on RC1 block that? I hope that is the case!!

Now on another topic, but completely related: the subfloor will go down first in the iso, with the new wall we've been discussing being built on top of that-is that correct? The actual floor space will allow me to build the wall laying down and to be stood up afterwards. If I understand your last post, I don't need to caulk the insulation inside this new wall, either then. Just put it in and drywall over top. Somewhere I read that it's good to caulk around the perimiter of the insulation after placing it in the walls...I believe it was a construction website-maybe they were just trying to sell more caulk.

"So=Subfloor + air (lots of it) + insulation + RC1 + 2 layers of drywall.

That looks like one mass to me. Are you saying this will be sufficient to stop noise from above? Currently I can hear when someone walks across the floor upstairs, and all I have is the Thermafiber up now. Will adding two layers of 5/8" drywall on RC1 block that? I hope that is the case!!"

OK, the ONLY mass that counts is one that is hermetically sealed. Framing doesn't count because it's not sealed, air can still move around it. Insulation doesn't count, air can move THROUGH it. In your case, the only things that would be counted as mass centers are your subfloor/floor (one leaf of mass, even though probably more than one layer) and the SEALED double or triple layer of wallboard yet to be added. Everything in between those two leaves is considered AIR space, because sound can move AROUND it without having to go THROUGH it. This is exactly what we want, because putting extra centers of mass between the two outer ones makes each air space act as a stiffer spring, therefore sound is coupled easier to the next leaf.

The extra air space is also a good thing - the further between the two leaves of a sound barrier, the better the isolation. If you were to just stuff R-19 fiberglas into all the nooks and crannies in your frame and put up RC and a couple layers of wallboard according to my drawing, you'd be amazed at the difference.

If you're hearing footsteps from above and they're LOUD, you might need to add a couple layers of wallboard up between the joists against the subfloor for more mass in that leaf - otherwise, you might end up needing 3 layers of wallboard on your ceiling, which is about the max for Resilient Channel - even then, the RC should be closer together to support the extra weight.

As to your other questions, you're on target there - it's much easier to build the wall frame laying flat on the floor than the way I described, so it's good you have the room.

The only reason I know to add caulking when insulating would be if you were insulating for HEAT instead of sound - even then, it's a ratio thing - a small hole in insulation makes almost NO difference to heat retention, unless the hole is also in the wall paneling so air can actually infiltrate through it.

Are we getting closer yet?

I've been doing this my entire life - and you do not caulk the perimiter of insulation - never been there -seen that - or done it.......

For what possible purpose would someone reccomend that ? It makes no sense to caulk something which will freely pass water/vapor/air.

I think either you missread something - or the site should be reported to the BBB.......

Rod

"Are we getting closer yet?" YES!

I'm not willing to go through the expense/hassle of trying to get up in the rafters to sheetrock...too much conduit up there, plus I would have to remove the existing runners, insulation, etc.
**SO, how about a layer of GAF instead of a third layer of drywall? And where in the layering should that be applied? To the runners perhaps, and THEN the RC-1/sheetrock? (This is from Auralex' website regarding Sheetblok: "most effective when used as one component of a multi-layered construction scheme.")
**The RC-1 will be mounted at 1ft. intervals for practicality AND strength. (The runners you see in pic #1 are spaced 1ft. apart.)
**Would you recommend screwing the RC-1 through the runners and into the 2x4 joists that the runners are mounted to? It seems to make sense to me, but then again, what do I know?

***Which flooring is recommended, T&G OSB or plywood?

"I've been doing this my entire life - and you do not caulk the perimiter of insulation"
Good enough! That's all I needed to hear-just saved me time/money/headaches and I got plenty of all that going on!

Steve, I want to thank you again for all the great responses/your time & commitment to this forum! I'm sure there will be subsequent questions as the construction continues. My main focus now is mounting the RC-1 properly (along the runners or across???)

Rod, thanks for helping out - my only thought on the caulk thing was that they were trying to "glue" the insulation in place - wierd, but you never know what people will come up with...

LSB, if you have a name it would be great if you signed posts with it - I ain't gonna call you "Luv", wouldn't want Michael to get mad

Sorry I don't have any time to answer stuff tonite, we had a serious fire at work while I was off and now I'm getting stuck with extra 12-hour shifts, so tomorrow nite will probably be soonest I'll get a chance - The good news is, no body was hurt in the fire , even though it blew a 3000 gallon solvent tank across the road and will end up costing over $1million to get straightened out -

Might get a few minutes in the morning, but don't hold your breath... Steve

Hi Steve...sorry 'bout the name thing. I used it on the first post of this page of our thread, but not in subsequent posts...my name is Dean. I guess I understand how you might feel uncomfortable calling ME Luv, even though the wall diagram you created for me (THANKX!) is called the Luvwall.jpg!!
After all this is "over" I might have to send you a case of Shinerbock-sound good?

I'm still looking for any repsonse about placement of the RC-1: ALONG the runners, or ACROSS the runners? Does it make any difference as long as I leave the 1/2" gap along wall perimeters? Am I sweating this stuff too much?
I just put up one strip of RC-1 ALONG a runner and found it was quite easy to drive a screw through the RC where there is no screw hole. I did this to secure the RC-1 to the 2x4 joists that the runners are nailed to.

****Here is my only thought about the placement of the RC-1: As I will be using two layers of drywall plus one layer of GAF (the Sheetblok equivalent), I think it best to screw the RC-1 ALONG the runners, as they are spaced 1(one) foot apart, whereas, if I placed them ACROSS the runners, they would have to be spaced 16" apart in order to drive the mounting screws into the 2x4s.
****1ft. spacing=more stability for the RC-1 to handle additional weight of layers.

DOES THIS MAKE SENSE TO YOU AS WELL?

dean

P.S. Sorry to hear about the fire at work-sounds like you have a dangerous job! That solvent is probably not very environmentally friendly either...

Hey Dean - you're right, I missed the one time you used your name -

As far as the RC is concerned, normally it's run ACROSS the last framing members (the ones it's attached to) but if that will put the existing mounting holes out of range you'd be better to run it along the runners. I've seen a couple of comments from manufacturers that they do NOT recommend mounting this stuff other than the pre-made holes (except of course for the wallboard that's mounted TO the RC - that's a different story)

USG recommends leaving a ONE INCH gap between the ends of RC and wall/ceiling intersections - and a 1/4" gap at intersections of wallboard itself, well-caulked. If for some reason you have to leave a wider gap, you can get foam "filler rod" to take up part of the difference, but I recommend sticking with the 1/4" if at all possible.

"quite easy to drive a screw through the RC where there is no screw hole." -

While this is true, it's not recommended. Not sure why, it's just not.

12" centers for the RC may be a bit close for only 2-1/2 layers of drywall - if you get the stuff TOO close together, you'll have too stiff a spring rate, and it won't do its job as well. If your runners are 12" apart, and laying FLAT, I'd think you would have no problem in finding coincidence between holes (real ones) and runners -

As to placement, some people (including manufacturers) recommend putting the limp mass FIRST on the framing (whether studs or RC) and others recommend sandwiching it between wallboard layers. My take on this is that part of the reason for putting limp layer first is damping of the wallboard - you will have your fiberglas insulation to do that, and placing the limp mass BETWEEN the wallboard layers adds ONE MORE speed change for the sound, making it that much harder to get through.

Even with 16" centers, you should be able to safely mount 3 layers of wallboard on RC - Of course, I would recommend getting this info direct from your SPECIFIC RC manufacturer - I heard that Dietrich recommends closer centers on their RC than some.

That particular solvent isn't very environmentally friendly, but preliminary tests indicated that the containment measures worked as designed, and everything was either burned completely or contained. Now it's just ripping out all the burned, melted and ruined equipment and replacing it - gonna take a while... Steve