Single room home studio for tracking and mixing

http://www.pac-intl.com/pdf/RSIC-1_EXT0 ... _Guide.pdf These instructions include specs on the RSIC clips - I would stick with this after looking at your piping nightmare. Each clip will support up to 36 pounds; if your joists are on 24" centers, two layers of 5/8 gypsum will work out to 24 pounds per clip. In your case, what with the ducting, etc, I would put THREE layers on the ceiling and two on walls, alternating ceiling, wall, ceiling, wall, ceiling. This would mean that the standard spacing of clips would MAX out the design spec of the clips - NOT GOOD. From looking at your pix, it seems as if your joists are on 16" centers - if so, and if the joists wouldn't be overloaded, I would use the spacing shown for 24" centers (every other joist, NOT every THIRD one) so three layers can be supported. IMPORTANT - Before you go off thinking I'm telling you you can DO this, I'm NOT (just yet, anyway) - first, I need to know exact dimensions of your joists - 2x8, 2x10, etc, spacing between joists, and maximum UN-supported lengths of joists, any place where a joist has been NOTCHED for pipe instead of DRILLED, what your upstairs flooring is - how thick, what material, how many layers, EVERYTHING you can think of that would affect strength. We don't need the death of musicians to achieve silence, it's much less painful to get it with design... :? Exhaust will be fine where it is, but if you MUST use metal make sure it's well-damped with insulation; the three layers I talked about (for the ceiling) are mostly because of your ducting... Steve

Hey, Steve - Thanks for the reply. Since we last talked :-) a lot has transpired, and you've hit on most of it. Given the state of affairs in the bays, we've decided to go back to hanging the ceiling, and I came across PAC's EXT04 clips in my research. I decided these would do the best job, particularly since, unlike with the standard RSIC clips, we can control the height of the ceiling with them, and by angling the ceiling slightly toward the back of the studio, the last 5 or 6 bays will be slanted sufficiently to miss the low-hanging gas line there, without putting a 90 notch in the ceiling. The existing ceiling joists are 2x10, on 16" centers. I've prepared a pathetic sketch of the layout of the joists, showing where the notches and drilled holes are for pipes and wires. There are 22 total joists, and a couple are doubled. Only 4 of the joists have notches (1"x1"), the rest are drilled holes (1/2" to 2") for the passage of wires and pipes. The electrical work for the studio has not been done yet, so I imagine there will be a need for more of these. If there is a narrow margin for error here, please advise, so that I can properly instruct the electrician. Back to the joists: they are unsupported in the studio room for varying lengths. In the unfinished area, the first 5 joist spans are 10'; then, beginning at the back of the studio, the remaining joist spans run from 10' 4" up 12' 4" at the other, widest end of the studio. If you need the length of EACH joist, let me know and I'll measure them. My contractor advises that the joists themselves are probably 13' 6" spans, from sill along the outer wall to where they meet up with the main beam in the garage, but of course this is an estimate since we've not opened the ceiling in the garage to verify. The remaining flooring above the joists is 3/4" plywood, topped with 1/4" linoleum in the back half of the studio. In the front half, it's 3/4 plywood topped with 3/4" hardwood floor (the north half of the studio is under the kitchen and the south half is under the dining room). As to the ductwork, we've won our battle with the town over the composition of the ductwork, so it'll be 1" Superduct rather than tin; they'll only require that we enclose the portion in the garage in fire-rated sheetrock. The layout will be similar to the sketch posted on 2/6/06 as ventilation overhead view2.jpg: http://www.johnlsayers.com/phpBB2/files ... w2_769.jpg Lastly, when I came across the EXT04 clips, I thought the best thing to do was to hang the ceiling utilizing their layout for 16" oc, optimized for 3 sheets of sheetrock (installation pdf on PAC's website), even if we only decided to go with two, and at least we'd have the option. But given our ceiling, and lack of 'beef' above, 3 would probably be better. In view of the calculation you've obviously got in mind, can you determine whether the joist/clip combination will support 3 layers of sheetrock, and at the same time NOT take all resiliency out of the clips? If so, I'd need more green glue . . . 8-) I acknowledge not knowing how to do these calculatoins, and I realize your assistance here will both (i) improve my room and (ii) potentially save my life. Believe me: I appreciate it. Thanks again. bzb

Oops, sorry! Here's the sketch . . .

Lookin' good so far; the notches are close to the ends of the joists so won't cause problems. Your worst case loading (plywood and flooring) figuring 2x10's on 16" centers, with just framing and upper floor layers runs around 7 PSF - adding a total of 5 layers of 5/8 gypsum (2 up, 3 down) would add about 12 PSF, about .5 more for insulation - total comes to just under 20 PSF dead load, and 2x10's on 16" centers will span just over 14 feet with 40/20 loading. If you want to stay more conservative, two layers under with GG would probably just about equal the performance; you'd need to ask Brian (studiotips) about that though, GG is HIS baby and I've not yet used it. If you decide to use three layers on the RSIC's, you will want closer spacing than they call for in the PDF; it's aimed at TWO layers, and three would put the clips too close to design max. Springs are only springs when they're not at the end of their travel, and the closer to max you load rubber the shorter the life. OTOH, if you load it too LIGHT, isolation will suffer so stay in the middle ground. Adding 2 layers of gyp under the floor and 3 suspended with standard fiberglass insulation, when properly sealed and overlapped, etc, should get you about STC 63 and around 35 dB TL @ 50 hZ for that ceiling - meaning, you would be at around 90 dB playing drums down there before anyone in the upstairs would know you're there. This is NOT a guarantee, since I'm not you and can't watch every thing that's done during the build; it's only an approximation. Don't let your "sparky" cut ANY notches, you're close enough to max that only HOLES drilled AWAY from the EDGES of joists should be allowed... Steve

Lookin' good so far; the notches are close to the ends of the joists so won't cause problems. Your worst case loading (plywood and flooring) figuring 2x10's on 16" centers, with just framing and upper floor layers runs around 7 PSF - adding a total of 5 layers of 5/8 gypsum (2 up, 3 down) would add about 12 PSF, about .5 more for insulation - total comes to just under 20 PSF dead load, and 2x10's on 16" centers will span just over 14 feet with 40/20 loading.

I don't pretend to understand that calculation, but I'm confused by your reference to 5 layers of sheetrock. Are you talking about 3 layers on the ceiling and 2 on the walls, in which case can you clarify for me how the walls in the studio work their way into the calculation? I'm not questioning, just trying to understand . . . hopeless, perhaps. It occurs to me that maybe you are referring to 'beefing up' the ceiling with the placement of 2 layers of sheetrock up there? I'll have trouble doing that for the same reason I couldn't hang a new set of joists across the inner wall. I do understand the principal that you are getting at, which is to say that the clips lose their beneficial effect when they are maxed out, i.e., are at the end of their resiliency (like a spring stretched all the way out), even though they may not be at their failure point. I do not understand how you used the weight load calculation above to get there. Perhaps it's not necessary that I understand on that level, but I had anticipated 2 layers of sheetrock on the ceiling, 3 if I could get away with it, and I seem to be hearing you say that 3 is not a good risk. If I understood your reference to 5 layers of sheetrock, perhaps I'd get it . . . ? I think I'm also confused by this:

If you decide to use three layers on the RSIC's, you will want closer spacing than they call for in the PDF; it's aimed at TWO layers, and three would put the clips too close to design max.

The following is a quote from PAC's pdf on their website: Oops, it's attached here as an image. Apples and oranges? Sorry, I'm just not getting this. Thanks for your patience. bzb

I WAS referring to putting two layers of gyp between joists for beefing up the upper floor, then hanging three MORE layers on the RSIC system, for a total of 5 layers. Calculated around 2.4 PSF per layer of gyp, plus weight of framing, plus weight of two layers of 3/4" wood flooring upstairs. Total, worse case, is still within spec for your joist spacing. I missed that part of the PDF, so was interpolating the 2-layer scenario - yours is fine... Steve

Ah, yes. Thank you for that clarification, now I understand. And if I cannot get sheetrock into the joists without removing the pipe runs, does it make sense to beef up where I can? I assume the weakest link theory would apply there? Perhaps sheetrock where I can, and lmv where I cannot? Even if I used 2 lb/sq ft lmv, I suppose I'd still be within spec? <Sigh> And if on the other hand, I simply hang the sheetrock on the clips, and skipped the beef due to the difficulty, the ceiling of my room would be somewhere significantly less than the 63 STC you hypothesized. Thanks for all of your help, Steve. It's been an extraordinary education. Cheapest course I ever took, too! bzb

Single layer 3/4 ply, same everything else, 3 layers 5/8 gyp on RSIC - STC 60, TL@ 50 hZ of 32 dB. This is assuming hermetic seal of course. Realistically, the rest of your construction may limit things anyway. And yes, weakest link applies - if you can't beef everywhere, and can't beef at least everywhere the floor is NOT double thickness, don't bother. One thing you could do that would likely get back AT LEAST the 3 dB from no-beef, would be using Green Glue between at least one layer of your lower three. And you're welcome... Steve

I understand, and had actually planned on GG/Sheetrock sandwiches all the way 'round (walls and ceilings). I'll check over at Studiotips with Bryan to see if GG will help 2x if I did 3 layers and added it twice. Thanks again. bzb

bzb wrote:

I understand, and had actually planned on GG/Sheetrock sandwiches all the way 'round (walls and ceilings). I'll check over at Studiotips with Bryan to see if GG will help 2x if I did 3 layers and added it twice. Thanks again. bzb

I didn't know whether to continue this, my thread, or start a new one, but figured this would work. We are now mostly finished with the construction, except for installing the 'floating' floor (i.e., not glued down - the flooring people use the word too freely), which I will be completing within the next few days. I will be testing the room, and hoping for some suggestions about treating it from you. First, though: Given the peculiar dimensions of this room, I'd planned on setting up the workstation at the southerly end of this room, which is the widest space, facing the narrow end. IOW, I planned to set up facing wall B, with the narrow end behind me (wall D). Is this best? or would some other orientation be better? I also expect bass traps in all corners, and absorbers set up around the mix position. But with such minimum ceiling height (7'2"), should I expect to skip putting a cloud up overhead? Thanks for any thoughts. bzb