Dan F's One-Room Garage Studio

Dan Fitzpatrick wrote:

. . . yes there will be some bowing toward the center, but some bowing is allowed right? (L/360 is about .43 inches at maximum load)? :?

It's not that bowing isn't allowed -- I realize that some bowing is to be expected. My concern is that the expected and allowed bowing of your new upper joists will put an unknown amount of inconsistent downward pressure on some of your existing joists which you do not know for sure whether or not they can handle. If you raised your new joists up higher so that there would be no contact between upper and lower joists, that would solve that problem. However, it would create a new problem in that you would no longer have the opportunity to apply caulk to the old joists to seal the gaps around the new gypsum panels. It's a "Catch 22" situation.

as long as the weight of the old joists is included as dead weight in my calculation it should be more than ok (since the old joists can easily hold just their own weight)

Again, it's not the dead load of the new joists that I'm concerned about. I realize you can account for the weight of the old joists upon the new ones. My concern is the weight pulling the new joists down and putting pressure on your original joists. Hopefully that's more clear. If not, I'm sure I can find another horse to beat. ;)

. . . my slow progression from "acoustic idiot" to "acoustic moron" (or is it the other way around?). . .

idiot. noun. a foolish or stupid person. moron. noun. a very stupid person.

Actually, by strict definition, one would (hopefully) start as a moron ("very stupid") and progress to an idiot ("foolish or stupid," but not "very"). Let the record show that I think you are neither -- after all, I have actually seen you in action on the whiteboard! :mrgreen:

. . . see also Keith's own thread here, which has been a HUGE influence on me and a guide on how to plan and communicate plans . . .

Let me just say that I owe as much to you as you think you owe to me, Dan! I'm delighted to have the opportunity to heckle you to justify your mindset on your plans, just as you did for (to?) me. :cool: OK, Dan -- 'fess up: What stage are you in? ;)

keith, between stage 15 and 20 there should be more of an up/down between "i've got it" and "i'm so confused i'll never figure this shit out" so if you could have a half-step between each "i've got it" of "i'm confused" i'm probably just coming out of the 3rd or 4th confused, heading once again towards "i've got it." i have to say, the more i think about it the more sense it makes to cut the slab and repour a new isolated "slab within a slab" or "slab island" BUT, the problem is, can we say with absolute confidence what the flanking level would be in such a system? keith, we were talking about this the other day. do we KNOW that no or little sound can flank through the ROCK/EARTH? inquiring minds want to know. but it seems like the simplest, neatest and maybe even cheapest solution. oh well, my wife already thinks i'm insane, so how much worse can it get. :P

Mmm-hmm -- notice the lack of any acknowledgement of the whole "joist bow pressure" thing? Eh? ;) Yes, someone please post all known (or intelligently guessed) information about the "island slab flank through earth" deal so that I too can get derailed again. ;) ;)

sharward wrote:

Mmm-hmm -- notice the lack of any acknowledgement of the whole "joist bow pressure" thing? Eh? ;)

hereby acknowledged. :roll: i dunno what to think about that. what's going to happen? those joists may be pushed down less than 1/2 inch what is the big deal? they are much longer so they should be able to flex more anyway ... i guess just wait until someone who knows what they are talking about chimes in ... :lol: cuz i sure dont

Yes, someone please post all known (or intelligently guessed) information about the "island slab flank through earth" deal so that I too can get derailed again

here's a lovely sketch i made ... does this look right?

"i did a test with my ear to the floor and a hammer and the sound doesn't travel across the sections" If the existing slab is already this good, how could an INTENTIONALLY isolated slab, with proper footings where needed for walls, not be AT LEAST as good? :?

knightfly wrote:

If the existing slab is already this good, how could an INTENTIONALLY isolated slab, with proper footings where needed for walls, not be AT LEAST as good? :?

I'll tell you how -- because we've become so cynical about this science over the past several months that we have become accustomed to (1) having a great idea, (2) finding out that it wasn't such a great idea, (3) having a greater idea, (4) finding out that sucked too, then (5) having the best idea ever. Just waiting for #6 to pop in and spoil the fun, Steve! ;) But seriously... Yes, everyone seems to be in agreement that this is a good (if not great) way to go -- everyone weighed in on mine already, and it was unanimous. We just want to make sure we're not (1) wasting money and/or (2) going to be disappointed with the results -- the same reason everyone is here. :) We Northern California Studio Builder Wannabes are rolling up our sleeves and about to get started very soon, and we just don't want to screw up -- we know y'all are watching us! (Scary and reassuring at the same time!) :mrgreen:

exactly what keith said ... we've been beaten down and don't trust common sense anymore. hey, if one wall stops this much sound, lets just put up another wall (or two) alongside it and it will be AWESOME BBBBRRRRZZZZZZT, WRONG ANSWER! what's that, you say theres some freaky RESONANCE frequency that pops up right when you need it least and screws up the wall? DOH! stuff like that can throw you. i wonder if i can get some buy-in from the studiotips crowd ... just ran it up the flagpole there. the hammer test was cool, it wasn't exactly done according to IRC protocol though. maybe there's some freaky resonance frequency where the two slabs are acoustically merged back together :shock: ... hey i've heard weirder things!!! :P

Yeah, I know the feeling; as late as 15 years ago I had drawings to convert my entire 36 x 48 barn into a studio; the purtiest set of quad-leaf walls ya ever did see... :oops: but the GOOD news is, in some places there were HEX-leaf walls, musta thought I was British :lol:

knightfly wrote:

. . . musta thought I was British :lol:

As in, Peterborough? :lol:

check out this thread ... good stuff maynard! http://forums.studiotips.com/viewtopic.php?t=1734 croupier, put my few remaining chips back on "floating" please ... d

"As in, Peterborough?" - No, actually as in "BBC" - as in "triple Camden" - as in "twice as much money in materials with no improvement in isolation" - our "Peterboro Pal" is sticking to mass-air-mass design AFAIK :wink:

I wrote:

. . . we've become so cynical about this science over the past several months that we have become accustomed to (1) having a great idea, (2) finding out that it wasn't such a great idea, (3) having a greater idea, (4) finding out that sucked too, then (5) having the best idea ever. Just waiting for #6 to pop in and spoil the fun, Steve!

Hey, look what just walked in... 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops:

sharward wrote:

I wrote:

. . . we've become so cynical about this science over the past several months that we have become accustomed to (1) having a great idea, (2) finding out that it wasn't such a great idea, (3) having a greater idea, (4) finding out that sucked too, then (5) having the best idea ever. Just waiting for #6 to pop in and spoil the fun, Steve!

Hey, look what just walked in... 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops: :oops:

damn dude, how long did that take to do?? :o

Been following that thread as well, but ATM I appear to be poised to take a new (sorta) direction in life that has the potential of an additional $100k+ per year income - this will be (is) impacting my "free" time drastically, so at this point I'm not sure just how much I can keep up with things here. I'll do what I can, but free vs. $100k+ (if it comes to that choice) is kind of a no-brainer, even to me. Hopefully I'll still be able to do both, maybe just not quite so deeply... Steve BTW, the number 6 was a wise choice so far (number of the beast) :?

mmmmmm ... additional $100k ..... :twisted: that's awesome steve, congratulations!! dan

Yeah, if it goes anywhere NEAR the apparent potential I'm gonna FREAK... 8) Oh, found this old thread just for reference, so you know it may not be as bad as the California Club may think - http://www.homerecording.com/bbs/showth ... adid=88275 If you're in a hurry, check out the top of the last page, for more detail read the whole thing... Steve

knightfly wrote:

. . . found this old thread just for reference . . . check out the top of the last page, for more detail read the whole thing

I just did (read the whole thing), and I'm afraid I don't see the relevance/point. Is that the correct thread? Or am I missing something?

if it goes anywhere NEAR the apparent potential I'm gonna FREAK

Yeah, and so is the worldwide studio builder wannabe community when they lose their beloved Knightfly to his Reitirement Plan 2.0! :shock: In all seriousness, I am genuinely thrilled for you 8) and wish you the ultimate best... But I'm also realistically mindful of what that will likely mean to us! :x ;)

Dan, you and I have spoken on the phone about how you might want to float the outer leaf wall closest to the street, since that wall would sit on the same slab as your inner leaf wall (as opposed to all of your other outer leaf walls that would sit on separate slabs). While knee-deep in Mason Industries' site, I came across their Neoprene partition supports, which you may want to consider for that...

External image, not preserved — original: http://www.mason-ind.com/images/neoprene_isolation/a107b2.gif

I'm sure you can do something "home grown" (including use of my EPDM! :wink: ), but just in case you want something more legitimately tried and tested, this Mason product appears to meet the need nicely.

at first i didn't get the point of these, but i realize now they are for attaching the structure to the floor without coupling it too bad. i'll look into these. wonder if you can get these without too big a minimum purchase.

Rod Gervais has commented on some of my recent "analysis" ... and it ain't good news ... :oops: but i'm glad as usual for his and everybody else's help. here http://forums.studiotips.com/viewtopic. ... 8294#18294 and here http://forums.studiotips.com/viewtopic. ... 8305#18305 Dan

Keithers, the point is the guy was trying to keep from having neighbors call the cops, had a limited budget, and was still successful with the budget methods I suggested. This was before I knew it was "impossible", according to the apostle Paul... :wink: OK, Paul, no flames :shock: I know your bunker's vastly superior to a few layers of OSB, not the point - BTW, you need to upgrade your "signature" - or are you trying NOT to scare prospective lurkers away with "over 1,000,000 pages and still climbing"... ?? :mrgreen: On another front, everyone don't panic; I'm not so easily gotten rid of, just a warning that I may take longer to respond during some phases of the madness... Steve

knightfly wrote:

. . . the point is the guy was trying to keep from having neighbors call the cops, had a limited budget, and was still successful with the budget methods I suggested. . .

Got it. :-) Indeed, some people's iso requirements are less severe and can be satisfied with less severe solutions. :cool:

. . . I'm not so easily gotten rid of, just a warning that I may take longer to respond during some phases of the madness...

Heh, we're used to THAT! :twisted:

So what am i thinking TODAY. as if anyone cares; i find that spewing my thoughts in a public forum helps me focus (sorry!) ... :P I've been giving a lot of thought to my slab, or slabs i should say, because they seem to be a limiting factor now to my design. there are two slabs that make up my planned studio floor. Rod's warnings and other info I have gathered seem to point to 50psf as the "safe" weight to allow for a distributed load. On the other hand it's pretty obvious that a point load of 1000 pounds plus is also allowed, because that's what a car tire does. I'm worried that if i put a wall that weighs 75 lbs per linear foot on the edge of one of these slabs, like i would want to, that it exceeds the allowed weight of the slab and the slab will crack. On the other hand, I have no problem driving my car up onto the edge of the slab in the exact same spot and putting 2000 pounds or so on it. So it seems like it would be ok to do the wall. Floating designs I have examined using a lightweight wood floor can get me down to 150 pounds per puck and if i put that on a 12" by 12" wood block that seems like it should count as 150 psf. that's still high by "official" standards but then i come back to my car tire that is 1000 pounds in less space. my room if i float will be 10000 pounds including 3000 pounds live load, using a multilayer wood and gypsum floor. here's the thing. i really don't want to make a major engineering project out of this, i want to get this thing going. here's what i'm thinking. forget floating, because the expense is too great versus the risk of major problems with slab cracking and settling, and there's no certainty that i need to float. build the first 75 lbs/linear foot wall along my slab edge and see what happens. if it cracks, maybe i'll have to disassemble the wall and demo the slab etc. but i won't be out too much. the expense vs. risk is not so much. but i don't think the risk is so much. if i can park 2000 pounds of car there (front wheels), i should be able to put 700 pounds of wall across roughly the same line. maybe after i've got a sense of how the slab is holding up, (was thinking i could measure the height of the slab before and after building the wall to see if the slab has flexed at all) maybe i'll reconsider floating the inner room. i think my slab will survive. if not, lesson learned the hard way. it's a risk, but i think a reasonable one. tearing out the slab and repouring it seems just too daunting. and perhaps unnecessary. there is risk too in doing something that is not needed isn't there? maybe the risk that the project doesn't get done AT ALL. the question now is, do i do 3 layers of 5/8 gypsum or 4 ... 3 will be less heavy on the floor, and realistically do i think my door and ventilation system will "keep up" with a 4 layer wall. maybe. one thing i realized today. 60 duro rubber is not going to work at all, even though i found a cheap source of 1 and 2" 60 duro neoprene in oakland, i'd have to put 300 pounds per puck or more on that to get the deflection i need for good iso. 130 bucks for 3 square feet of 2" neoprene not bad ... left the name at the office but i'll provide later. 50 or so dollars for the 1" ... at least i think that was neoprene, it may have been rubber. 300 pounds per puck ... can my floor handle that? aaaarghhh. maybe it can. but using the softer KIP pads that can be used at 150 lbs/puck is probably a safer bet if i do decide to float. unfortunately the KIP pad route is more like $400+ versus the $130 for the rubber. maybe i just need to find out how soft a rubber i need for about 20 psi to give me decent deflection. certainly 60 duro is way too hard. and $270 is cheap insurance and relatively small expense compared to the whole project. so why worry about it. sorry to ramble, but maybe someone else will get something out of this, or make a suggestion (other than, SHUT UP) :twisted: anybody have any slab-cracking experiences they want to share? cadesignr? do i see your hand up? :wink: Dan

Heres a very educated guess without seeing your slab. I've been building houses and running construction jobs since I've been old enough to pick up a hammer, and I have an mechanical engineering degree.( i telling you this to qualify my statement as I'm new here.) I think you're intuition is dead on about the weight of a car versus the weight of the wall. The car is exerting about 1000 psf, all in one spot (8x8" area). The load of the wall won't be nearly that much because the load is distributed over the width of the plate times the length of the wall. If you're paranoid about this you can distribute the load more by simply using a wider plate ie: 2x6 instead of 2x4. You can still however, use 2x4s for studs, just put the studs flush to the plate on the finished side of the wall. I don't think this is necessary however.

Xalky, thanks for your reassurances. Now i have someone to blame if it cracks :twisted: haha just kidding. Dan