Floating Floors revisited........revisited again.

[Jai]

O.K. All.

I was here made the construction plans, went over to see john in the design area, came up with a great design, built the outter leaf of the system (Will Post Pix this week) and was getting ready to float the floor and build the second leaf. I had a local studio builder, he's done some pretty massive projects with great success, anyway.....

He says that the $1000.00 to float the floors is wasted money if i'm not doing it a certain way. That the way I was going to do it would not net the results of $1000 and labor to do it. So........

I got to ask again, Knightfly, Kase, John, GOD......anybody ,

Here is the idea I had and fine tuned here, PLEASE PLEASE correct my probs and let me know your opinons as fast as possible. i have a crew standin around pickin their ass at this point. I guess I am second guessing and need some reassurance.

here be the diagram: And Thanks for all the great help!!!!!!!

[cadesignr]

I used MDF 3/4" myself. Two layers. On 2x6 joist/framing. One thing I observed though. When I built mine about 8 years ago, it was modular, as I was renting(dumb!) I ended up having to take it apart(doh!), and as we lifted the floor modules out, I noticed that because concrete floors are RARELY perfectly flat and level, that the neoprene pads had settled unevenly. That meant that the weight on certain pads increased, as other pads did NOT even touch the floor. That translated into springyness in some floor areas, and overcompressed pads in others, which totally negates the decoupling spring from those pads that were overcompressed.
If you are using very thin pads, like 1/4", I suggest they won't work. Steves suggestion of making tests and weight analysis is totally right on. Otherwise, you might as well build the floor directly on the concrete. Or forget it altogether, as you may well waste your time and money chasing a decoupling scenario that is doomed by failure to really understand the scope of this weight.
I haven't followed this whole thread, so I don't know your intent
but if you are building a "floating room" on this concrete floor, with walls built on this "floating floor", the weight of this type of construction is significant. Especially if you are using two layers of gyp. bd. on ceiling and walls, not to mention the floor decks themself. I read of one studio that was calculated to weigh at 30 TONS!! Not that a typical home studio room in a room weighs that much, but I would not fly by the seat of my pants in guessing this if you are truely intent on success. But I am a novice at this, having only one attempt at floating a room under my belt, but never even finished it. Thank god I didn't. Disassembly proved my "theorys" were hogwash even before building walls. Wish I would have had this forum around then. I would have "met" Steve even earlier!! And maybe he would have talked me out of building in a rental. What a moron!! hahahahaha!
I do have a suggestion though. As you frame this floor, make sure each pad is touching, as you may end up having to shim between some of these pads and the frame or floor. I've seen concrete floors vary as much as an inch between the perimeter and the middle of the concrete floor. Take a long straight 2x6 or an aluminum extrusion, and lay it across the floor and check in several locations, directions and diagonally before starting. It may keep you from having to stop and think about things. Also check for levelness. I've also seen floors that were a joke. Even modern concrete floors. Makes me wonder about the skill level of some concrete "form" carpenters. If you do find it is out of level, start at the HIGH point, or you may end up at some undetermined area, unable to even put a pad in place. And then have to go back and shim EVERYTHING up to that point. Well, I'm no expert, but experience stands for at least a portion of education. Even if its only .02

fitZ:D

[dymaxian]

The design you posted looks to me like it'll work. What did your contractor recommend you do? Can you afford the $1000 for him to do it?

Kase
www.minemusic.net

[knightfly]

Rick makes some really good points here -

My question is, what does your expert think is necessary, and why? And, what type of facility/noise isolation, etc, are you building? Which floors are you planning to float?

One thing to keep in mind when floating floors - the lower frequency you want to isolate, the more mass (and air space) you need in the floated floor. There comes a point where you're better off pouring a concrete slab on commercial floor isolators. Short of that, adding a couple layers of gypsum between heavy plywood will help quite a bit. Rockwool between the floors with a density of 3 PCF ( 48 kG/m^3) is better than spun glass. EPDM rubber will do the same job for at least twice as long as neoprene (about 10 years vs maybe 25)

Resting the walls on top of the floor adds another design problem - as Rick said, walls get heavy and will require more support around the edges than the rest of the room, except maybe where pianos, heavy consoles, etc, will sit. Your suspension needs to be compressed somewhere between 25 and 50% of its total range in order to work - remember that a spring is only a spring when it's NOT at its ends of travel (either fully compressed or fully extended)

Auralex U-boats are made of EPDM rubber, and they have spacing recommendations on their site, it may be in their FAQ (don't remember for sure) so that's one possible plan.

If you can only float one floor in a single studio, I would normally recommend floating the room the drums will be in - if outside noise is a problem, then you'd need to also float the CR, and for that matter ALL rooms, to keep from recording trains and planes and random gunfire

Just don't float ONE floor and put all rooms on it, thinking you've accomplished much - that won't give anywhere near the room-to-room isolation you want for a studio. Also, if you do your walls floated on the slab and not on the floated floor, be sure to include a perimeter isolation board (celotex or homosote works, caulked thoroughly) - some type of resilient sway brackets will be necessary to keep walls from hard contact as well.

Sooo, what does your studio design guy like for floated floors? Steve

[Jai]

thanks to all for replys.

my local guy did not give me the exact floor system. I have not hired him to do the job. I just do not have the budget. He came by for the first talk and look at the space and my design. While asking me questions that's when the floor system was brought up and told that my idea was no tgoing to give the benefits of 1000.00 plus labor. Now, I will say, if I had the budget I would hire him cus I have seen his rooms and they are impressive. But He is used to good, $50,000 - $750,000.00 budgets. not mine i will tell you.

anyway....back to the floor.......

i hear all you are saying. i have floated a floor before and got the springyness talked about above. Used the U-Boats. But it was my fault for leaving too much space between uboats and for using curved 2x6x16s.

I did plan this time a bit better, i have taken weight into acount and used knightflys calculator of wieght. I came up with 1/2" neoprene with a duro of 60. i told the guy at Midwest (got the number here under construction matierial) and told him my intention, weight, and dimminsions and got a go ahead on the springyness and compression of the pad.

I guess I am just second guessing here. I built a big freaking diving board last studio floated floor and because of other bad bad mistakes basically felt like I designed an ampitheater instead of a soundproof room. So, because of the other screw-ups on that room I do not know if the floor worked or was the sound leak. I dont know if It isolated or coupled to the floor and passed a lot of lowend out to the room thru the slab.

This time around I have a partner, a money partner, I am basically supposed to be the working partner with all the knowledge to build this thing. Yes, i do have the knowledge or when I dont have the sence to talk with people like ya'll. But my problem is if it was my money and I screw up no prob. I kick myself for about three years like before and it goes away. With someone elses money????????

also, yes each floor in my design is floated. The control room, tracking room, and iso in studio A. Plus control and Iso in studio B. All with their own floor system. Inner leaf will be on floating floor. Outter leaf(already Done) is on concrete slab.

Starting to ramble i know.

Anyway, does the diagram look right except I heard someone say rockwool instead of pink stuff (spun). someone said 2x6, is the extra 2" gained from this going to really help with the low end?

i swear, I am not one to get ideas here go out find another idea then come back to ya'll to say it wont work. I am just second guessing. Looking for reinforcement to what I already feel is a good way to accomplish my goal. Any ideas or pitfalls to avoid would be great. i will build the floor Monday Morning if all approve.

jai
www.themixstudio.com

[knightfly]

I'm really short on time this morning, but I'd say you can stick with the 2x4's if spans aren't a problem - but I'd go heavier on the floor materials. 1/2" OSB, even two layers (they will flex individually, do NOT glue them except possibly at joists) just isn't good with 24" spans. I would put 1-1/8 tongue and groove ply down, then 5/8 sheet rock then 3/4 MDF and your finish floor. That will lower resonance. Rockwool is denser than the fluffy fiberglas by several times, and will do more to kill resonance. You could also add a strip of the fluffy stuff between joists before laying the first floor layer, to help dampen floor vibes.

Gotta run, I'll check back tonight... Steve