FINISHED IN 2020! Sharward's Partial Garage Conversion

Thanks for the post. However, even that still doesn't have a firm answer. And even past that, I'm now aggravated that Varilight doesn't make those touch sensitive/remote controlled dimmers for a 120V AC system. Those are so cool looking.

Based on research I have done over the last 3 days, my floorplan has to change dramatically due to California Building Code requirements for landings at doorways with stairs behind them. I do not have the CBC book in front of me. However, based on feedback from my city's building department (which I have corroborated with numerous sources on the 'Net), CBC §§1003.3.1.6 and 1003.3.1.7 require a door landing (or a floor) on each side of door. The landing must be a minimum of 36" in the direction of travel. There is an exception for doors at the top of interior stairways where the door opens away from the stairs. In my original plan, my raised floor is about 15.5" off the concrete slab floor of the garage, requiring two steps up. I had planned to have one step between the doors, with the outer leaf door above the surface of the slab even with the first step, which would minimize square footage wasted between the doors. Bzzzzzzzzzzzzzt: Wrong answer. :cry: I revised the plan, putting the outer leaf door at slab level, with a 38" deep unobstructed area inside of it, plus two steps up of equal height. The second step is the same height as the room. Fortunately, since the inner leaf door opens into the room, I need not have a landing at the top of the steps. Since I now have the room inside to swing the door inward, I changed that. (That's the one silver lining in this -- I no longer have to worry about hitting my car with the door if I park to close to the wall.) Making these modifications causes me to lose 23 square feet -- down from about 133 to about 110. 110 feet? Criminey - that's just one linear foot larger than our dinky bedrooms. :evil: This 1/6 reduction in square footage is really pissing me off. It's not like I had a lot of room to afford in the first place. In light of this discovery, not floating my floor would give me back a great deal of floor space. I'm now stuck between a rock and a hard place: floating the floor gives me good isolation, but may make the room impracticably small. I also placed the 8" HVAC vents, based on my HVAC bidder's recommendations. I also was aware that a garage must have a minimum witdth of 10' and a minimum depth of 20'. In closely reviewing my plans and doing some careful measurements, I discovered I had inadvertently interfered with that area that must be kept clear by a few inches. I could steal back about 20 square feet by encroaching on the space on the right, below the laundry room. However, that would result in an awkward zig-zag path to/from the house and cut out some prime storage room in the garage. Mrs. Sharward would not be pleased with such a prospect, and nor am I to be honest. :( The other thing that sucks about this is that I have to redo all of my framing plans, my weight calculations, etc. It's almost like starting over. :cry: :cry: :cry: Oh well... Better I learn this lesson now, on paper, than after construction began. If anyone has any miracle ideas that I'm just missing, please share. Thanks.

Am I insane for considering this? I get back almost all my lost square fotage, plus I eliminate the "rectangleness" of the room which would improve acoustics. It also makes the lower part of the room more usable by expanding the length of the perimeter walls.

would something along these lines work? it gives you a smooth path from house to studio, with a little jog to get to the cars ... plus, the potential weak link of the door points away from your neighbor. dan :?

Dan, you rock. 8) Thanks for the idea and for sketching it up for me. Actually, my original "before I found this resource" drawings called for a similar plan in terms of door placements. However, I have decided against putting the door in that area, for a couple of reasons. First, makes loading and unloading gear a little more challenging, as opposed to the "straight shot" that having the door along the outer wall features. I also anticipate a certain amount of come-and-go traffic of fellow musicians through the garage's side exit. (This is not for commercial use, of course. Second, my wife has already expressed concern about obstructing the path from the house to the cars. The 90-degree turns one must take from house to cars in your sketch will, I am sure, not pass the "wife test." ;) (Figure that she often has her hands full with groceries or pet supplies or other awkward objects.) While I did not expect her to be especially thrilled with my "insane plan" proposal (which features the same type of zig-zag, but "softer" due to the 45-degree angle), she put up a much greater amount of resistance than I expected. :roll: It's hard not to give the wife what she wants in this, given how supportive she has been throughout the whole process. I am, however, toying around with a similar "raised landing outside the room" idea where the doors are currently planned. However, my challenge is that I have the vents on the exterior wall that I cannot block. Or, maybe I can block them and then install a vent register in the side exit door. However, that could present a problem fitting a car on the left side. Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa Thanks again for your idea, Dan.

How 'bout just clipping the corner, like this? You'll never notice the floor space loss, the traffic flow around that corner will seem easier, you keep your air lock, etc... However, is there also a requirement for a 10x20 area for the LEFT side of the garage? Not following this totally - If you still need to discuss, I'm (barely) available from 8 to 9 tonite (Monday) - but you might wanna think about ramifications - if so, I also have the 8-9 hour open on Tuesday, and possibly Thu or Fri... Steve

knightfly wrote:

How 'bout just clipping the corner, like this? You'll never notice the floor space loss, the traffic flow around that corner will seem easier, you keep your air lock, etc...

Clipping the corner does resolve the 10x20 encroachment issue. However, it doesn't make up for the square footage lost to the landing.

. . . is there also a requirement for a 10x20 area for the LEFT side of the garage? . . .

No. Technically, the garage must have a minimum area of 10x20, which I have marked off with a pink box. That area must be kept clear of construction materials -- no steps, no nothing. The area to the left of that is up for grabs, technically. However, I am choosing not to chew into that area too much, as a personal (not code) requirement is that I maintain space for two vehicles. (Space for two cars may be a CC&R requirement as well.) I also cannot block the vents (although I might be able to cut vents into the side exit door in lieu of the wall vents -- I'm not sure). Your illustration blocks one of my vents -- actually, it puts one of the vents inside the sound lock on the outer leaf. :shock:

If you still need to discuss, I'm (barely) available from 8 to 9 tonite (Monday) - but you might wanna think about ramifications - if so, I also have the 8-9 hour open on Tuesday, and possibly Thu or Fri...

Yeah, I've got some thinking to do. :roll: Maybe I'll do my "insane plan" minus the bulge on the right or something.

this place is gonna rock when its done. :D

I redid my plans to account for the landing and reconfigured all the framing specs. I thought long and hard about wood-vs.-steel framing, and chose wood (again) just because of familiarity (which is funny, because I've never done any framing before). But the latest frustrating obstacle is the issue of the EPDM. Based on feedback I received from day one here, I moved forward with that as a foundation of my plans, literally and figuratively. However, my building department wants legitimate specs which appear impossible to come by. In fact, I'm finding out that the manufacturer of a particular EPDM floor floatation product doesn't even recommend that they be used to float concrete. This means that my entire floating floor design either lacks sufficient documentation to prove its structural integrity, or the whole plan is worthless. Disheartening is an understatement to describe how I'm feeling about this. I've spent months researching, studying, asking, detailing, posting, tweaking, posting, tweaking, posting, and in spite of it all, I feel like not only that I am at square one, but I'm not even allowed to roll the dice yet. This is supposed to happen to people who rush into things, not to people who are diligent and careful and mindful and methodical. A less dedicated individual would throw up his hands and say, "F*%& IT!" At times I wish I could do that. Yet, I know deep down that would only hurt more. I know I need to move forward, but I'm so lost right now that I don't know which way is forward and which way is backward. So, I remain standing still. Whereas in the past I've asked for feedback, I suppose now I ask for encouragement... And ideas would be welcome too.

just a thought,but check this http://www.kineticsnoise.com/arch/rimconcrete.html and http://www.kineticsnoise.com/arch/flm.html. These floors might be expensive, but they are simple and might have the correct documentation. Dont worry, I'm exhausted too. The thing is you have to reach for the impossible, and then accept the acheivable. The closer you get to impossible, the higher the acheivable gets. Ive added lumber, increase costs, and complicated the plan, but, if I wouldve went with my origanal plan before everyones help, I would have used almost as much lumber for a system that doesnt work. Now even if I have to settle for some things I cant get, it will be far better than the origonal. Do what you can with what you got, and get those drums out of their bags and start remembering why you decided to spend your time reading about drywall.

Keith, I know you're feeling down, completely understandable; not sure what I can do right now, so I'll just throw out some thoughts; First, did you ask your BRA why it's OK to put flammable TAR under your floor, but not flammable EPDM? Second, you've DONE the calculations for EPDM based on REAL testing; there is no difference between using U-boats for a WOOD floated floor and using them for a MASONRY floated floor, considering you would be adjusting spacing and contact surface area (puck size) to achieve the same amount of compression. I see no reason whatsoever that this would even enter into the equation. I get the impression that Auralex has done little (if any) actual testing on their floor floating materials; otherwise there would be more technical info available on their site - customer education is almost NEVER a BAD thing, unless you're selling "snake oil". Third, consider this (I know you won't like it, but consider it please) - For the isolation levels you're after, you could get better results by going with a more commercial method; i.e. using kinetics or mason ind. spring jacks under a 6" CONCRETE floated slab. Advantages; lower floor level overall, more mass, less BS trying to lay bricks and mortar evenly, full architectural specs available, adjustable for sag AFTER the fact, MUCH quicker install... If I'd remembered just how obdurate most BRA's can be, I would have tried harder to talk you out of your brick floor - for one thing, brick isn't as high mass (usually) as concrete, for another once this is in place I doubt seriously whether you will EVER actually "dig up" a section - for another, being able to lower your floor level and still get maximum isolation HAS to be a plus. That's about all I have for now; as you know, I'm kinda "in it" myself ATM... Steve

Keith, Sorry to hear about this roadblock ... one idea (based on zero experience but hey it's free), talk to local contractors/architects. maybe they will have ideas on how to get the planner what he needs. you are doing something unusual yes, but buiding things using methods not in "the book" can't be uncharted territory. every builder has probably run into this at one time. maybe it's as simple as hiring an engineer to test and certify your epdm as suitable for what you're doing ... then maybe your bureaucrat will have what he needs to cover his ass, which is probably all that is going on. he wanted documentation, give him documentation. of course that will add $$ to your budget. there are probably (i hesitate to say) builders attorneys who know how to get through this stuff too. basically, the guy isn't going to listen to your arguments, but you can maybe get someone he WILL listen to in your corner? You've come very far, but let's face it, you only recently went to the planning commission and started to feel your way around. you didn't think they were just going to stamp OK on your plan did you?? :P you will find your way around this roadblock i'm sure. One other idea ... get out your wallet and say, "maybe my friend mr. washington can persuade you ..." Dan

http://kineticsnoise.com/arch/tests/pdf/A15-b.pdf See table 2, 80 hZ - this is wood floated on RIMs/KIPs - http://kineticsnoise.com/arch/tests/pdf/A13-b.pdf See table 6 - this is 4" concrete floated on RIM. Note the 9 dB improvement @ 80 hZ of the concrete vs. wood. Mass rules down here. 50 dB TL @ 80 hZ would equate to a room volume level (drums) of at least 95 dB in the room, before it would be even slightly audible outside. Add background levels outside, and someone standing right beside your wall might be able to tell you were playing drums inside, but only barely... Steve If you upped the concrete to 6" (with appropriate changes in RIM material) those figures would improve by about 3 dB at the low end -

Thanks for the ideas and encouragement, everyone. Much to digest here, and fortunately I have a weekend free to do just that. Laptop battery dying; have to abanon the telecommute option today to go to the office to pick up my power cord. :? Anticipate more thoughtful response this weekend. Y'all rock. 8)

Keith, just got off phone with Kinetics guy, looks like 6" concrete/ply/RIM system would run you about $1200 (no labor, but includes cost of concrete + plywood) - resonance of system around 14 hZ. You would need to level the floor though; no practical way of putting "legs" under it. Don't know what self-leveling concrete would add to cost, you might check locally on that??!? Later... Steve

I was wondering when someone around here would start talking about the Kinetics floor systems. A studio designer I used to work for used this almost exclusively for his floating floors. For small rooms especially, this seems like the most pain-free install there could be.

Me too. I hardly ever see mention of it as a solution. Although, I just did in another thread below. At least a roll out type. fitZ

What a relief -- I know what direction to go in and I'm going in it. Ahhhh, to be unstuck (again). 8) We're at 7 pages on this thing and over 4,000 page views -- seeing these numbers and the thoughtful responses are really encouraging. Not only am I not alone in this, but I'm helping others avoid the same pitfalls. In short, by helping others, I help myself at the same time. :) Many have contributed in the past week and my responses (if any) have been weak. Here are answers to your questions, acknowledgements of ideas, blah blah blah...

mikeklooster wrote:

just a thought, but check this http://www.kineticsnoise.com/arch/rimconcrete.html and http://www.kineticsnoise.com/arch/flm.html. These floors might be expensive, but they are simple and might have the correct documentation.

You know how sometimes the answer is right in front of you and you just can't/won't see it? Well, it looks like you nailed it, Mike, so you get the prize for suggesting it first! :D I had taken the EPDM ball and ran with it, assuming it was the way to go, and in the process I (obviously) turned a blind eye to the other solutions. (At the defense of EPDM, it is still a way to go, but the lack of documented specs makes using that method impractical in terms of meeting some municipal inspector scrutiny.)

. . . you have to reach for the impossible, and then accept the acheivable. The closer you get to impossible, the higher the acheivable gets.

I have read those words several times over the past few days, and each time I read them, they become more meaningful to me. 8)

. . . get those drums out of their bags and start remembering why you decided to spend your time reading about drywall.

:lol: You're so right, Mike -- in fact, after weeks of constant badgering by a few coworkers, I'm finally going to bite the bullet and join Skip's Music's Weekend Warriors next weekend! I'll probably be one of the youngest guys in the program, but it promises to be a lot of fun while not consuming so much time that I can't get some good drywall reading time in. ;) Now, onto Steve's stuff...

knightfly wrote:

I get the impression that Auralex has done little (if any) actual testing on their floor floating materials; otherwise there would be more technical info available on their site - customer education is almost NEVER a BAD thing, unless you're selling "snake oil".

Yes, I agree. I'm not going to go so far as to say they're selling snake oil (and I realize you're not necessarily saying that either), but I will say that they seem to have something in common with the snake oil people in that there's not sufficient data made available to (1) prove that their products actually work as advertised and (2) convince building department bureaucrats worldwide that they're structurally safe and reliable. Hopefully they're plugged into this thread and will benefit from this feedback... Or they can prove that we're incorrect. Either would be good.

. . . you could get better results by going with a more commercial method; i.e. using kinetics or mason ind. spring jacks under a 6" CONCRETE floated slab. Advantages; lower floor level overall, more mass, less BS trying to lay bricks and mortar evenly, full architectural specs available, adjustable for sag AFTER the fact, MUCH quicker install...

Agreed: commercial method now officially adopted. [gavel slam]

If I'd remembered just how obdurate most BRA's can be, I would have tried harder to talk you out of your brick floor - for one thing, brick isn't as high mass (usually) as concrete, for another once this is in place I doubt seriously whether you will EVER actually "dig up" a section - for another, being able to lower your floor level and still get maximum isolation HAS to be a plus.

Well, the fact is, if I go with a solution that is tried and tested and has bulletproof specifications, then the likelihood of having to do a major repair or adjustment underneath the floor is greatly mitigated, if not completely eliminated. In short, if there are no rubber feet, there are no rubber feet to fix. Amen to that!

Dan ''The Man'' Fitzpatrick wrote:

. . . you only recently went to the planning commission and started to feel your way around. you didn't think they were just going to stamp OK on your plan did you?? :P

:lol: Exactly! What I really hoped to find out is whether I needed to provide more details in the form of calculations (such as load distributions, span table excerpts, etc.) for some of the construction. Although I knew there was always a possibility that they'd want to shut it down for one reason or another, the "landing" thing really surprised me, and I honestly didn't expect it would be so impossible to provide meaningful specs on the EPDM.

One other idea ... get out your wallet and say, "maybe my friend mr. washington can persuade you ..."

:lol: I just about fell on the floor when I read that! :lol: CLASSIC. 8) Thanks for all your other thoughts and suggestions, Dan. Since I'm no longer pursuing a method that isn't well documented by official sources, hopefully I won't have to go to the lengths you proposed. :)

knightfly wrote:

http://kineticsnoise.com/arch/tests/pdf/A13-b.pdf See table 6 - this is 4" concrete floated on RIM. Note the 9 dB improvement @ 80 hZ of the concrete vs. wood. Mass rules down here.

Great stuff.

50 dB TL @ 80 hZ would equate to a room volume level (drums) of at least 95 dB in the room, before it would be even slightly audible outside. Add background levels outside, and someone standing right beside your wall might be able to tell you were playing drums inside, but only barely...

:D

If you upped the concrete to 6" (with appropriate changes in RIM material) those figures would improve by about 3 dB at the low end -

If I'm going to go through all the effort to do 4", why not add the extra 2" for better isolation -- right?

looks like 6" concrete/ply/RIM system would run you about $1200 (no labor, but includes cost of concrete + plywood) . . .

Hey, that won't break the bank -- and not having to lay all those bricks won't break the back! 8)

You would need to level the floor though; no practical way of putting "legs" under it. Don't know what self-leveling concrete would add to cost, you might check locally on that??!?

Yes, I've been thinking a lot about this over the past couple of days. My garage floor is essentially level in the "panhandle" (rear left) area, and then it slopes about ¼" per foot. This means that a straight board laid on the floor from back to front would have a fulcrum near the middle. As far as laying the Kinetics RIM material and the plywood goes, that shouldn't be much of a problem -- I can run a seam along the point where the slope starts. However, building a concrete form with an uneven bottom may be a little challenging. I'll probably have to lay an oversized board onto the floor and snap a level chalk line, then use a circular saw to trim off the excess...? Or maybe I can see if the retired gentleman down the street from me with a wood shop in his garage would be willing to make a few cuts for me...? Thanks again, everyone. Removed INCORRECT illustration so that it doesn't confuse people

In another thread, cadesignr wrote:

My own experience with building a HEAVY wood floating floor on an existing "4 concrete slab ended up cracking it.

Hey Fitz -- should I be concerned about this? (I'm thinking YES. :shock: )

I'm finally going to bite the bullet and join Skip's Music's Weekend Warriors next weekend!

8) :lol: I'm a veteran of the Skips Music Weekend Warrior WARS!! :P We won. I took no captives. Pure EXTREME PREJUDICE!! Hahahaha! Have fun Kieth! BTW, say Hi to Skip. I worked at Skips store for three years.

Hey Fitz -- should I be concerned about this? (I'm thinking YES. Shocked )

Well, Kieth I don't know. The slab that I had my floor on was an OLD seperate garage, that was in a low spot in the field out behind the house. Looked like maybe water had formed around the slab numerous times from flooding. It might have cracked from areas under the slab being washed away or maybe settleing. Your garage is new, contractor built, designed for a car(probably heavier wire grid) and a gravel bed. But you never know. I would think it would be ok with your weight distribution, but it might be wise to consult someone with real engineering knowledge, since you are putting brick on the floor. Not much lighter than a floating concrete slab with all the wood support I would think. Anyway, thats why I mentioned it in the other thread. This is AFTER the fact design, as far as the slab is concerned, and it MAY not handle it. I hope someone DOES know and can tell you for sure. Sorry. I do know this though. This is a complete room with a heavy floor, and even small buildings with the same proportionate weight are usually required to have a perimeter footing at least TWICE as deep as your slab probably is. Maybe more, I don't know what code calls for. Maybe BID can tell you. Thats the best I have to offer. I've often wondered about this though, and even mentioned it on a few forums, but no one ever responded with a negative experience. One person who is an engineer agreed with me once though. That tells me something. fitZ added later: :roll: HOLY CRAP. Just read the whole previous thing about using 6" concrete floating floor.....er...I think :? Is that what you are doing...hmmm. Boy, things change fast around here :lol: Hey Kieth, I see you found out what I meant about Sac BID :wink:

cadesignr wrote:

. . . BTW, say Hi to Skip. I worked at Skips store for three years.

Will do!

Your garage is new, contractor built, designed for a car(probably heavier wire grid) and a gravel bed.

All true. Not only do I have the advantage of having a new (5 year old) home, the builder is big (Beazer Homes) and still doing big business in the area. I also have the cell phone number of one of their Water Intrusion Managers whom I keep in touch with now and then (we became acquainted last summer when a $75,000 plumbing fiasco displaced us for several weeks). An example of the usefulness of this resource: I called him a few weeks ago to ask if the garage floor had a membrane under it, and he instantly answered in the negative. He also assured me, as best he could, that there should be no plumbing under the garage floor.

. . . it might be wise to consult someone with real engineering knowledge . . . I hope someone DOES know and can tell you for sure.

Thanks for the advice, Fitz.

I see you found out what I meant about Sac BID :wink:

Ha! :lol: Well, for what it's worth, I'm not blaming them for the lack of official EPDM testing spec's. Although, the concern about flammability is stupid. Maybe I'm just fooling myself into thinking that I don't hate their guts just to get through this ordeal. They just care about public safety and they're not on a power trip. They just care about public safety and they're not on a power trip. They just care about public safety and they're not on a power trip. There. Got it. Really, it's quite blissful! ;)

The Kinetics rep for Calif. is in SF; company name is Tempco, and the man to talk to is Dan Hornak - [removed] Main office contact is Jason Earlich - [removed], Architectural div., X209. Installed prices for the FLM series (spring, screw jack, poured in slab) runs approx. $12 per sq ft (6" slab), whereas the RIM system runs approx. $6 per sq ft installed; you will need to talk to your LOCAL rep to pin down costs for just materials. Jason didn't recommend the extra expense of the screw jack system for most applications; the RIM system would require extra KIP pads around the perimeter, for that you'll need your weight calculations that the walls/ceiling will add to your floor. A 5.5" thick concrete slab will weight approx. 66 to 68 PSF without any wood or framing; you already have the weights of your walls and ceiling. To pour self-leveling concrete (remember you're only leveling the floor at this point; the floated slab comes later.) Take a straight 2x4 that's at least as long as the uneven part of your floor; set one end on the highest point, then put spacers under the opposite end until a level resting on top of the 2x4 reads dead center. Next, take a drawing compass, insert a felt tip or other high visibility marker where the pencil normally goes; adjust the compass so that with the pointed end resting on the floor next to the LOWEST floor point, the marker rests against the bottom edge of the 2x4. Holding the compass with the marker directly ABOVE the pointy end (trammel), drag the trammel point along the concrete maintaining contact between the marker end and the side of the 2x4. What you should end up with, is a line along the 2x4 that is exactly parallel to your uneven floor; if you cut this line with a jigsaw and throw away the bottom part, , you should end up with a board whose irregular bottom edge should match your floor contour, and the top edge should be level. Repeat this on both sides of the garage, they may be different. Take a 5/8" masonry drill and drill holes through the existing slab every 3 feet or less along the outside of these "form" boards, and drive 2' long rebar pieces down thru the concrete until the top of the rebar is flush with the form board at each point along its length. This leveled "mini-slab" should extend under your outer walls (new sides) so your outer leaf will be level - standard J bolts can be added, as well as a thermal break such as sill seal, double 30# building felt - this is your outer leaf, so none of this will hurt isolation. Perimeter Isolation Board would be laid against the inside of your outer wall frame, and the RIM rolled out in place - hell, you can read - http://kineticsnoise.com/arch/pdf/rimc_install.pdf 'nuff said for now, I agree that 6" slab makes more sense in your case; when you talk to Dan, he may have the same questions about "overkill" as Jason did; I just explained that you wanted the ability to thrash drums at 3 am without your wife or neighbors finding more creative/disgusting/painful uses for your drumsticks... Steve

Shar, Looking this over I have the following comments, The direction you're heading is a pretty good choice, The 6" slab is (IMHO) better not because of the additional isolation - but rather because of the lower center frequency (resonance) of the slab itself. When you start talking islation in the area of 50+dB at 80hz, you are going to spend some serious money to match that with the remaining assemblies. But you would hate to have the slab create a problem due to it's resonant frequency. Building Officials hate to see anything outside of their experience just sort of "pop up" - that's why they want to see details. Of course - if one hires a licensed engineer to provide calcs and a stamped drawing - they will accept it as an "alternative design". But that get's fairly pricey. As far as concerns with cracking goes, I have to say I am a bit nervous with the idea of pouring over the existing garage floor slab. Personally I would remove it - then pour a thicker level slab with rebar reinforcement placed in the bottom 1/3 of the slab - before constructing my elevated slab. Remember - this was not designed to carry this sort of a load - and you could have problems with cracking due to settlement, the chances are that the builder did not place any reinforcement in this slab - as typically that would not be require for a simple garage slab. At most it might have some matting - but that never winds up being where it's supposed to be (which is in the top 1/3 of the slab - not the bottom - this for shrinkage control - not structural loading) but more probably only contains fibermesh in the concrete (once again for shrinkage (crack) control. OK - that's my 2 cents worth. Rod

Here's a close-up of the area we're talking about... <img src="http://home.surewest.net/sharward/studio/straightwide-cropped-small.jpg"> (ENLARGE THIS PHOTO)

rod gervais wrote:

. . . I am a bit nervous with the idea of pouring over the existing garage floor slab.

Thanks for weighing in, Rod (no pun intended!). Yes, I'm nervous about it too.

Personally I would remove it - then pour a thicker level slab with rebar reinforcement placed in the bottom 1/3 of the slab - before constructing my elevated slab.

WOW. :shock: This is beginning to take on a life of the "bunker project" in the UK!

Remember - this was not designed to carry this sort of a load - and you could have problems with cracking due to settlement, the chances are that the builder did not place any reinforcement in this slab - as typically that would not be require for a simple garage slab. At most it might have some matting - but that never winds up being where it's supposed to be (which is in the top 1/3 of the slab - not the bottom - this for shrinkage control - not structural loading) but more probably only contains fibermesh in the concrete (once again for shrinkage (crack) control.

I just got off the phone with my builder buddy... He said he's almost certain that there's at least a 6" square thick wire mesh in the garage floor, and it may even have rebar in it. He said that my friendly neighborhood permit center would have the plans and that I could see and copy them there. I will try to do this tomorow morning. So, let's assume for the sake of argument that my existing concrete floor will not handle the additional weight of the 6" floating slab + walls + ceiling. Let's assume it won't even handle a 4" floating slab + walls + ceiling. M-A-M is heavy -- the greater the mass, the greater the weight. I'm wondering if I can "cheat" the laws of gravity by using an expensive product like QuietWood Solitude (4.4#/ft²) for my floor on top of the Kinetics Floating Wood Floor, and living with an unlevel floor in the room. The walls would still firmly attach to the walls, and the ceiling would still firmly attach to the walls. I fully appreciate that conventional wisdom around here is that the QuietSolutions products are extremely expensive compared to what can be achieved with conventional products, careful design, and meticulous construction techniques (which is why we're all here). However, I'm between a rock (needing good iso) and a hard place (gravity, structural integrity). I also realize that by going thinner, I'm looking at resonant frequencies and probably inferior low end TL... What I need to determine is whether my neighbors and I can live with those limitations -- and most importantly, whether I will be within the confines of my city's noise ordinances:

Objective (8.68.060 Exterior noise standards) Subjective (8.68.190 General noise regulations)

I also know that although low end is harder to control, it is also generally harder for humans to hear... So perhaps I can get some clarification on that, perhaps in the context of this chart: <img src="http://www.phys.unsw.edu.au/~jw/graphics/Fletcher-Munson.gif"> In short, I need to know the numbers I must achieve, and whether or not my alternative QuietWood + Kinetics RIM will achieve them. And once I have that, I'll redraw all my plans again. :?

I have the name/number of another Kinetics rep that handles the NW, will try Mon. or Tue. to see what he has to say on loading, etc... Steve