Steve, what's up again? It's Chris from Chicago. I just wanted to ask you a few questions just to make sure I'm understanding some of the major topics in the reference/faq sticky.
1) I'll have 3 rooms (4 counting an airlock) all within one outer shell. Since I plan to use separate frames (mass-air-mass) for each room, then I won't really need RC for any of the walls right?
2) Should I still use different materials when layering or is that principle geared more toward single frames as well?
3) Yesterday, I read through a caulking and sealing thread and you had written that you only should caulk around the perimeter of the wall as a whole, not each panel. My question is should each layers perimeter be caulked or just the final layer? Oh yeah, sorry about that wrong link yesterday to the adco site. If you get around to it, the correct address is http://www.adcocorp.com
The stuff I asked you about is called ST-30
A few questions for knightfly
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cyeazel
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- Location: Chicago, Illinois U.S.A
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knightfly
- Senior Member
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1) I'll have 3 rooms (4 counting an airlock) all within one outer shell. Since I plan to use separate frames (mass-air-mass) for each room, then I won't really need RC for any of the walls right?
Right.
2) Should I still use different materials when layering or is that principle geared more toward single frames as well?
The (almost) short answer - while you get some "smoothing out" of the coincidence dips (weaknesses in TL) present in gypsum at around 2 kHz by using different thicknesses, it's been since determined that this isn't as important as the better low frequency isolation you can get with more mass -
Further, trying to keep track of different thicknesses of wallboard on a job site is a major PITA. This is because bass frequencies are much harder to stop than higher ones, so by the time you get the bass under control you've "over-engineered" the wall for mids and highs, making it a "non-problem".
Because of these two reasons, it's now recommended to just stick with 5/8 standard (not Firecore) gypsum for ALL layers, fastened according to USG's handbook (link available in the REFERENCE section)
3) Yesterday, I read through a caulking and sealing thread and you had written that you only should caulk around the perimeter of the wall as a whole, not each panel. My question is should each layers perimeter be caulked or just the final layer?
In all cases, but ESPECIALLY in your case with the butyl rope, you need to do EACH LAYER as you go. That way, no one small crack/gap can negate your otherwise careful work. Remember that even a 1/64" crack a few feet long can lower a wall's performance at lower frequencies by around 10 dB - that's like going from 4 layers of wallboard to only two layers each side.
Bear in mind though, that this does NOT mean ignoring full mud and tape for all seams IN THE FIELD (all NON-perimeter joints) - most wallboard has its long edges tapered to make room for a smooth mud/tape job, so if you don't mud/tape the UNDER layers in a multi-layer wall, you're creating TWO problems - lack of mass (more is always better) and multi-leaf problems (even a 1/16" void between layers will have SOME negative effect at higher frequencies)
HTH... Steve
Right.
2) Should I still use different materials when layering or is that principle geared more toward single frames as well?
The (almost) short answer - while you get some "smoothing out" of the coincidence dips (weaknesses in TL) present in gypsum at around 2 kHz by using different thicknesses, it's been since determined that this isn't as important as the better low frequency isolation you can get with more mass -
Further, trying to keep track of different thicknesses of wallboard on a job site is a major PITA. This is because bass frequencies are much harder to stop than higher ones, so by the time you get the bass under control you've "over-engineered" the wall for mids and highs, making it a "non-problem".
Because of these two reasons, it's now recommended to just stick with 5/8 standard (not Firecore) gypsum for ALL layers, fastened according to USG's handbook (link available in the REFERENCE section)
3) Yesterday, I read through a caulking and sealing thread and you had written that you only should caulk around the perimeter of the wall as a whole, not each panel. My question is should each layers perimeter be caulked or just the final layer?
In all cases, but ESPECIALLY in your case with the butyl rope, you need to do EACH LAYER as you go. That way, no one small crack/gap can negate your otherwise careful work. Remember that even a 1/64" crack a few feet long can lower a wall's performance at lower frequencies by around 10 dB - that's like going from 4 layers of wallboard to only two layers each side.
Bear in mind though, that this does NOT mean ignoring full mud and tape for all seams IN THE FIELD (all NON-perimeter joints) - most wallboard has its long edges tapered to make room for a smooth mud/tape job, so if you don't mud/tape the UNDER layers in a multi-layer wall, you're creating TWO problems - lack of mass (more is always better) and multi-leaf problems (even a 1/16" void between layers will have SOME negative effect at higher frequencies)
HTH... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
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cyeazel
- Posts: 247
- Joined: Sun May 01, 2005 1:24 am
- Location: Chicago, Illinois U.S.A
Thanks a lot. Man, separate frames makes things so much less complicated. Might take up more space but I don't need to worry about RC here but not there or two layers this side but three layers of a different material over there...etc.etc ; my head was spinning. Just out of curiousity, is there a substantial mass or acoustical difference between standard and firecore gypsum, or is that not why you recommend standard? Oh and you answered another question for me before I asked reguarding the 3 layers. I figured that if I had enough mass to stop the lows, then the mids and highs would also be taken care of also, but I wasn't sure so thanks for answering that before I forgot to ask. So I guess I have your approval on the butyl rope then too eh..?, cool, more savings.
Oh, one last thing..... sand fill between floated floor joists better than mineral wool, agree or disagree? Or is it not that simple and it depends on a number of other factors?
Oh, one last thing..... sand fill between floated floor joists better than mineral wool, agree or disagree? Or is it not that simple and it depends on a number of other factors?
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knightfly
- Senior Member
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- Joined: Sun Mar 16, 2003 11:11 am
- Location: West Coast, USA
X code gypsum is approx. 7% lighter than normal and costs more; by the time you get even TWO layers of standard gypsum up, you're already beyond any normal fire ratings. The X core stuff was (I believe) made so a single layer wall between garage and living space could be 1-hour fire rated. Since mass is the main thing for TL, it's a waste of money to spend more for less mass.
Rod's the man on sand filled floors, done a bunch of em - try a search on gervais (author) and sand. I'm almost outa time for now, if you don't find what you're looking for we'll try again... Steve
Rod's the man on sand filled floors, done a bunch of em - try a search on gervais (author) and sand. I'm almost outa time for now, if you don't find what you're looking for we'll try again... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
