RC-1 vs staggard stud wall

Hi all... I hope this is an easy question... All else being the same, which would give me the better sound proofing, especially for the lower F's? I have two options... 1) Staggard stud wall - with 2x6 plates and 2x4 studs, with insulation and one sheet of 5/8th drywall. 2) standard wall - 2x4 plates with 2x4 studs, insulation, and one sheet of 5/8th drywall hung on RC-1. As you see the only difference is the RC vs the staggard stud... well a bit more insulation becasue of the extra width of the staggard stud assembly. I assume that adding a second sheet of drywall to both systems would help the same amount in both systems... true? I know that double wall would be better but that is not my question. thanks for your help... jam

See Gypsum Board Walls: Transmission Loss Data (IRC-IR-671), published by the NRC Institute for Research in Construction in Canada. --Keith :mrgreen:

assuming your intent with the staggered stud on the 2x6 is to have another wall on the other side, why not put the RC on one of the walls in that scenario? i.e. combine option 1 with RC.

Is there some reason this discussion is happening in a new thread instead of a continuation of the original thread you started on this topic back in February? :roll: Part of the problem with having multiple threads is that it's difficult to keep track of the information given and the advice/answers/feedback given in response. From the original thread, it seemed you were agreeable to doing separate frames, which will be far superior performance. It wouldn't surprise me if staggered stud performed better at some frequencies and worse at others due to the widening of the gap (good) and the flanking path of the plates (bad)... gulfo's point about using RC on the staggered stud walls would likely lessen the flanking, but it pushes the first layer of drywall into the room another 1/2" or so. That makes your framing a total of 5 3/4" thick, whereas double frames would be (at minimum) 7 1/4" thick, a difference of only 1 1/2" -- which leads me to the obvious question of why double frames aren't on the table for discussion right now. :?: Whenever someone brings up staggered studs here, I for one always try to talk people into doing separate frames, primarily because so many folks coming to the forum don't even know they're better and are simply moving forward with the assumption that "staggered studs are the best for isolation." I know this because I was one of those people! :lol: Really, I think your best bet is to start over at the beginning. How about starting a new thread that contains all the information we asked for in the "BEFORE YOU POST, YOU MUST READ AND FOLLOW THESE INSTRUCTIONS" announcement thread. You seem to be intent on just asking seeming simple "A or B" type questions, but the best advice will follow a full-fledged introduction with lots of detail, particularly in the areas including (but not limited to) existing construction, square footage, layout, obstacles, environmental surroundings, how much isolation you need, and of course, budget. In the absence of that, I think I'll have to resort to answering all future questions with a generic and slightly smart-assed "It depends." ;-) --Keith :mrgreen:

gullfo wrote:

assuming your intent with the staggered stud on the 2x6 is to have another wall on the other side, why not put the RC on one of the walls in that scenario? i.e. combine option 1 with RC.

In reading Rod's book it says there in "no advantage" in using rc on a "true" double wall system. I thought that this would be simliar to a staggard stud system also. That is why I thought it was a "A or B" type quesstion. But maybe since it is not a "true" double wall RC WOULD be of benefit. So doing both Staggard stud with RC would not be considered redundant and a waste of money? Still it does keep adding to the space and space is at a premium. But it is getting closer and closer to "oh well, forget the space"...lol I guess I may need to look at cost of double wall vs staggard stud w/rc. Probably cheaper to go double. I have an average outside SP level of about 67db(c) read with a Radio shack meter. So if I can get 40 to 50db from the walls then I should be fine for a 100-105db live practice. I measured an average 50-51 db inside the space with no work done (ie; just outside stucco adn bare studs inside) I thought 17db cut so far is pretty good. jam

Do you live within Sacramento city limits? If so, you'll want to familiarize yourself with the City of Sacramento's noise ordinances. They are in two parts, which I call objective and subjective. We must be in compliance with both standards. --Keith :mrgreen:

if you can go with the double wall, do it, if not the RC on the wall should be cost/space effective but not as isolation effective.

jamminji wrote:

I have an average outside SP level of about 67db(c) read with a Radio shack meter. So if I can get 40 to 50db from the walls then I should be fine for a 100-105db live practice. I measured an average 50-51 db inside the space with no work done (ie; just outside stucco adn bare studs inside) I thought 17db cut so far is pretty good.

thing is you need to measure this with bass frequencies since they're going to penetrate your walls "like a hot knife through butter".... you need have 105db 50-250 hz sine waves going on when you measure - and heed Shardward's info on sound ordinances...

sharward wrote:

Do you live within Sacramento city limits? If so, you'll want to familiarize yourself with the City of Sacramento's noise ordinances. They are in two parts, which I call objective and subjective. We must be in compliance with both standards. --Keith :mrgreen:

HOLY Cow! Yes I live in Citrus Hts... From 7am-10pm 55dBA! (is 55dBA what my RS meter reads?... is dBA "A" weighting? I did "C") They do not specify "where" that is measured but still VERY low indeed. At least they give me the out of being able to stay at the ambient (67db in my area) noise level. But even that is open to what they mean by "encompass the ambient noise level". I hope getting from 105db to 65dBA is going to be enough! Especially when most of the systems I can afford only cut about 20db from the low Fs. I guess it depends on if my neighbors like the music. Also thanks for the pdf for stc's. Excatly what I needed! I had seen others but this one is great! A bit hard to understand exactly what is differenet in some of them, but good info for sure. jam

Jam, you don't live within City of Saccramento. You live in City of Citrus Heights. They have their own ordinances. See if they have the codes posted on their Web site. You may have to go to City Hall to get the language. Gulfo's got the picture too. Remember: "cool" neighbors today can move away and be replaced with "uncool" neighbors tomorrow. Neighbors have a right to peaceful enjoyment of their property, indoors and out, windows open or closed. Also, interesting tidbit: City of Sacramento raised the fine for noise ordinance violations to $1,000 per incident (after one freebie I think). Each 15 minute period constitutes a separate violation as I recall. --Keith :mrgreen:

Ok I am getting confused here... I am reading all over the place here, that rc is not needed on a staggard stud wall. see below... knightfly wrote: You're right about the walls being thicker when staggered studs are used - you must have absorbed this comment several posts ago - "plus, the 2x4 walls will eat up 3" less total space inside the room than the 2x6 staggered ones will. " - Here's an idea of the staggered stud wall - the dark brown is the bottom and top plate of 2x6, and the studs are 2x4's - the insulation gets woven through the studs as shown. The non-staggered stud wall is shown in the earlier drawing; the difference in wall thickness for each wall would be 1-1/2", even though the top and bottom plates are 2" wider - the staggered stud frame doesn't need Resilient Channel, which takes up about 1/2". The straight 2x4 frame DOES need RC in order to isolate inner and outer leaves of the wall. Because your room is small enough already, the straight 2x4 frames with RC makes more sense. For your ceiling, you can't use 2x4's because they aren't rated for that long a span - you'll need to use 2x6's instead, even if you place them on 16" centers. The simplest way to do the ceiling/roof without running into problems with moisture/rot is to first build your sound proofing leaves, and then put a simple roof over that. I'll try to get an illustration for you in a few days... Steve And i saw another from Rod... but can notfind it now. Anyway I am more then happy to put rc on but if it is not needed then I would rather put the money into gear. Rod?Steve? please help me. I am just about to build the door and need to know if I have to add another 1/2" thanks jam

jamminji wrote:

Anyway I am more then happy to put rc on but if it is not needed then I would rather put the money into gear.

Jam, reality is that you get a slight benifit form RC channel on a staggered wall - but not what you would get by adding another layer of drywall - The biggest gain with RC on this wall is for frequencies above 315 Hz - which is where your problems lay....... Here is test data on 2 walls taken from the IRC -IR761 study. TestID TL-93-251 2x4 staggered w/ f.g. insul dbl 5/8 ea side STC 57 50 Hz 21.0 63 Hz 21.8 80 Hz 25.3 100 Hz 32.0 125 Hz 36.4 160 Hz 38.7 200 Hz 44.1 250 Hz 51.7 315 Hz 55.0 400 Hz 56.8 500 Hz 56.9 630 Hz 57.3 800 Hz 59.3 1000 Hz 61.0 1250 Hz 62.6 1600 Hz 60.3 2000 Hz 53.1 2500 Hz 53.7 3150 Hz 60.2 4000 Hz 65.5 5000 Hz 69.5 6300 Hz 75.0 TestID TL-93-216 2x4 staggered w/ f.g. insul RC-1 1 side, dbl 5/8 ea side STC 62 50 Hz 20.0 63 Hz 21.9 80 Hz 28.9 100 Hz 35.8 125 Hz 37.9 160 Hz 42.6 200 Hz 47.8 250 Hz 54.1 315 Hz 57.4 400 Hz 61.1 500 Hz 65.2 630 Hz 67.5 800 Hz 70.9 1000 Hz 72.0 1250 Hz 74.4 1600 Hz 73.8 2000 Hz 66.6 2500 Hz 65.2 3150 Hz 71.7 4000 Hz 75.3 5000 Hz 78.7 6300 Hz 82.1 I guess the bottom line is for you to look at the potential gains and determine if that little improvement in the low frequencies still makes using it worth while. Sincerely, Rod

Ok... one last question on the RC1. Naw, probably not... ;) I have the insulation (r19) in my staggard stud wall and the insulation pushes out from the plane of the studs, especially where the oppostite studs are. When I screw in the rc channel the insulation pushes against the RC1, and when I screw the drywall to the RC1 the screw will touch the insularion and could even break the vapor barrier. I have not found any application instructions that deal with this. Am I worrying about nothing or do I need to fix this situation. If so how? I suppose I could cut the insulation down the stud and place each 12' half into the cavatiy. thanks... jam