Will she hold, captain?!

I know I we be soundly beaten with a trout for not finding this out sooner, but I think I discovered this site a little too late. heh. Anyway. Im working on a little studio in my basement. Nothing too fancy, but I am putting some money into insulation and drywall to keep transmission noise from upstairs to a minimum. Too many of my recordings have little voices in the background shouting "DADDY! HE BIT ME!" and other such things.. I digress.. So I put up some 1x3 furring strips to get around a couple obstacles, slapped up the resillient channel, stuffd the space between the joists (16") with some R30 and I went out and boughta butt-load of 5/8 drywall and some 1/2 celotex. As I am lugging the drywall in it is dawning on me just how damned heavy this crap is. My plan was to screw the 5/8 DW into the RC, slap on the 1/2" celotex and then but on another layer of 5/8" drywall. So my question is.. what is the likelyhood of me being killed in a tragic recording studio accident? I probably have the RC too far apart for this.. It is all screwed in about 14" from the center of one RC to the next. If you dont think the ceiling can handle the weight of 5/8.cel.5/8 what other options do you think I should persue? Again, I have to balance what is "right" with what I can get away with. damned wife and her worries about feeding the children. bah! let them eat cake!

Cake is cool, long as it doesn't cover up the taste of the pizza, then it becomes unhealthy... You didn't mention the vertical depth or the span of your ceiling joists (vewy importante), but your RC is actually plenty close (unless it's the wimpy, wall-only kind) For 3-layer ceilings, RC on 16" centers is plenty close even if all 3 layers are sheet rock. Use Wood type screws fastening the RC, and use at least 1-1/2" long to fasten the RC to the joists. Where you're fastening to furring strips instead, it could be different. Are your furring strips parallel to joists or perpendicular? How sturdy are their fastenings to joists? If none of this is a weak link, and you use a 12" spacing on screws holding the paneling to the RC (staggered 4" each layer) you should be fine. Still need vertical depth AND span of your joists so I can tell you whether to stay put, or only record "smashing pumpkins" down there... Steve

Ok.. Im not entierly sure I follow your banter sir. (forgive the monty python reference) but I will do my best to answer your questions.. the joists are 9" deep. IM not sure what you meant by the span of my cieling joists.. measuring the room parallel to the joists is about 11'1" the room is actualy 11'1x16 if it matters. I did use 1 1/2" wood screws to screw the RC in. the furring strips I did along the length of the joists (which would be aprralel i guess) rather than across them. I hope that was right. I really am not a carpenter. I only play one on TV. I used 1 5/8" scrwes and liquid nails for attaching the furring strips. I glued and screwd the snot out of them. thanks for your help! J

You should be fine then. Rc is quite strong considering it's flexibility. :) I Only wish you had put in some Roxul AFB in that ceiling instead of Just R-30 (Possibly R-19) Bryan Giles

hmm. well I have some R19 laying about the place. or if I needed to I could go grab a couple more bags of R30. and stick that in there too. I didnt because I thought some air between the floor above and the insulation was a good thing? not sure what Rockwool is though?

The issue is for density, the denser the matarial (as long as it not too dense) the better. AFB from roxul, or rock wool, mineral wool, etc... is denser than the pink stuff therfore cutting down sound transmission more effectively.) www.roxul.com they are a canadian company. Bryan Giles

I guess I should add this, what you have done is fine if it's already done. Don't Sweat it. The difference is marginal. Bryan Giles BTW the way I thought R-30 was 9" thick? Maybe I am wrong. :)

heh. the stuff I got says it is 10 1/4" thiick, so I guess the whole idea of air between the insulation and the floor above was kinda pointless. Good thing I dont do this for a living! :oops:

You got what I was hinting at huh? LOL The AFb comes in thickness of 1.5 to 4" and is way more effective at absorbing sound. Oh yeah, and It's cheaper to according to my cost estimates. I did an entire ceiling 10x13 for about $30 dollars using 3" AFB. The sheets (2'x4') costs 56 cents a sheet. Bryan Giles

Looks like you're in good shape all around - if your joists measure 9", they're most likely 2x10's which are usually an ACTUAL 9-1/4" deep. They are plenty strong enough for the weight of 2 drywall and 1 sound board layers. Bryan covered the rest, so you should be good to go... Steve

Well, a buddy of mine and myself spent from 6 pm to 12:30 am putting up that ceiling. 1 layer of 5/8 , 1/2 celotex, and another layer of 5/8. My body feels like a train hit it. It's hell getting old(er). I had no idea how claustrophobic 7'2" feels. Seems like the lack of trasmission noise from upstairs is pretty good now though. Im pleased. now I need to do the walls. Im going to do RC on one side of the wall. Do you think I'd be better off using 3 layers of drywall on each side? or doing the same thing I did with the ceiling? (i.e. drywall, celotex, drywall?) R13 insulation seem ok for the walls? or should I look for this magic fur that Giles was talking aboot? Where does one get this sort of thing? Home depot and Menards are the only worlds I know! thanks a bunch guys Jason

Jason, Well if this helps, I ripped all the R-13 I had put in my walls out and redid the walls with the Roxul. I Put in a call to Roxul to find a distributor in your area. You will yield much better damping and absorption in your wall cavity with the AFB/Rockwool, etc.... Roxul is a subsidiary of Rockwool International. Just the North American branding is Roxul. The Drywall/Celotex/Drywall is an excellent way to go. As Steve has described the difference in materials changes the way sound transmits which of course sound is like electricity always looking for the least path of resistance. In this case your are changing the components and thus improving your Transmission Loss. Bryan Giles

Here yah go... Bob Turley [removed] Crystal Lake, IL He carries the AFB and the RHT-40 products. I'd recommend the 3" AFB for the inside of your walls See people, this is why we need you to fill in the location part of your profile. So we can help research distributors and such like for yah. Bryan Giles

Thanks for that Bryan, please be sure to post it in the Materials area - this kind of info is at least as helpful as the "how" part... Steve

thanks so much Bryan! that was certainly above and beyond the call. what a great board. :) And thank you too steve, for the info! :)

Just a quick update.. I called Bob Turley about the AFB and he wasnt interested in selling to me. said they werea wholesaler.. but he did give me another number. Rosel Building materials [removed]. They didnt sell Roxul products but had USG products which the fellow said was pretty much the same thing. Said the 3" x 24" rolls were $20.54 and covered aboot 64sq. ft Do you guys know about this stuff? is it worth getting?

Great, I did a followup Make sure you get the 2.5pcf Density SAFB I Spoke with a gentlemen named Bruce 3" x 24 x 48 = $20.54 64sqft (8 Sheets) or .32 cents sqft. Twice what I payed here, but still a good price. Bryan Giles

Excellent. I'm gonna go buy some this weekend! :) Another question.. maybe this belongs in the acoustics section.. but.. where the HECK can I get this OC 703 (or 705) stuff? I am sure I am going to need bass traps and diffusors in this little room of mine. I have looked around and called everyone I could think of.. nobody has this stuff. Im thinking about just dialing random numbersand asking whoever answers the phone if they have any 703 in their garage I could buy off them. If 703 cannot be found can this mineralwool be used in it's stead? Seems like I read someone around here had done this?

I Used Mineral wool instead of 703 on my live room walls. They make a Semi-Rigid Mineral wool with a density of 3 to 4pcf. That is what you need to look for. Plus it is like 1/4 the cost of 703. Just cloth cover and run with it. Bryan Giles Actually (I am editing this post) the thermafiber makes a 1" 4pcf product which is semi-rigid. You can use that. The Roxul RHT-40 is the comparable product and comes in sizes from 1" to 4" I used 2" on the Live room walls and I used 4" In my control room for the angled rear walls. See Studios under construction -> Patricks Den Recording Studio. Hope this all helps.

The ongoing battle of getting Owens Corning to sell us mere mortals their precious 703 series of insulation is a real pain in the ass. I guess we're just not a massive enough force to cause them to take notice... The only success we hear about is people calling every commercial drywall/insulation contractor in a 40 mile radius of their location and asking about it. When members of this forum do that, we REALLY appreciate their posting the results (if positive) in the Materials forum so others can benefit. There are other nearly identical products available, unfortunately STILL considered a commercial product - Knauf is one, and Insulco in Australia - Knauf is primarily Euro, but has outlets worldwide. Other products, like mineral wool and rockwool (some of which are regurgitated floor sweepings from metal manufacturing) have different physical properties and somewhat different acoustic properties as well. Rockwool is actually just a trade name for mineral wool. There is also a product called slag wool, which is the byproduct of metal manufacturing if I remember correctly. For the inside of acoustic walls, ANY insulation with approximately 3 pounds per cubic foot density seems to fill the bill. It works better if it lightly contacts the inside of the wallboard, because damping the wallboard reduces the Coincidence Effect that partially "shorts out" sounds in the 2-4 kHz range. For uses that require the insulation to be "in the room" with us, acoustically the fiberglas versions seem to have slightly better balanced absorption and are a bit more manageable. Other than that, you're pretty much on your own for sources. One other option, if you're desperate, is that Ethan Winer now offers a couple choices of 700 series fiberglas on his website - http://www.realtraps.com/fiberglass.htm The further you are from Connecticut the less desirable this option - plus, you should be able to do better locally on price IF you can find it. I'm only posting that link as a last option... Steve

Hey Knightfly, this was my reason for going the rockwool way.... 2" is what I used in the Roxul RHT-40 for my live room walls 703 ASTM C 423 ________ 125 250 500 1000 2000 4000 NRC 703_____ .17 .86 1.14 1.07 1.02 .98 1.00 RHT-40___.26 .68 1.14 1.13 1.06 1.07 1.00 Had i used 3" Roxul RHT-40 These are the specs _______ .62 1.03 1.20 1.10 1.08 1.10 1.00 And at the price point I won't miss it. 18 difference in coef. at 250 does not cause me to get nautious. the 4" is even more even. I Used this on the rear of my control room ______ 1.07 1.01 1.07 1.06 1.07 1.06 1.05NRC 2" 703 runs .74 / sq ft and RHT-40 runs .25 cents (2") / sq.ft to .41 cents (4")

Lookin' good Bryan; did you post your source info in the Materials forum? Thanks... Steve

Yeah there should be a LOOOONNG listing of info I posted a while back Bryan Giles