Should I build a False floor.

Posted: Sat Mar 08, 2003 10:02 am

Hi

Can someone please give me some advice.
I am building a small studio. I have an end unit and only have one unit next door to me which is empty. I intend to build a second wall but probably not a room within a room as i'd lose too much space, and its already quite small as it is.... There is nobody underneath, or above. only next door and opposite. Should I or do I need to build a false floor? If so, What would the false floor achieve? as there is no-one underneath, is it important?

Lee

Posted: Sun Mar 09, 2003 5:53 am

Lee,

Isolating the floor might help a little if you have loud drums and bass amps, and other such things that shake and vibrate. A floating floor can decouple that vibration from the beams and structures that in turn transmit sound throughout the building. But since so much sound will strike the walls and ceiling, which in turn connect to the beams and structures, isolating the floor will not be as effective as also isolating the walls and ceiling.

That's my best guess anyway. Smile

--Ethan

Posted: Sun Mar 09, 2003 10:15 am

Hi guys, here's my $.02 on this question:

Floating floors are rarely necessary for good studio design, but the average man on the street has heard the phrase "floating floor" repeated over and over to the point where it's considered almost synonymous with the concept "professional studio". This is a myth that truly needs debunking, right up there with the one about using egg-crates to "sound-proof the garage". Most people who float a floor in a garage, basement or whatever have no idea why they're doing so other than they've heard that's what they should do if they're building a studio. And sadly, quite often they build a flimsy, acoustically nightmarish wooden structure on top of a concrete slab that would have been preferable by far. And they give up the one side of the box that was already truly soundproof- isolated by the enormous mass of the earth itself. Although this wooden floor may provide some bass-trapping, it's not necessarily of the right type, and you wind up with boomy low end vibrations traveling up the mic stands when walking around the room,and lose valuable inches of ceiling height, to say nothing of the considerable waste of money and effort. And then there's compromised handicap access, and on and on...

So when is a floating floor called for? First, there are many types of floating floors- some are concrete floated on special jacks, some are wood,and some are merely sandwiches of materials of different densities. Different situations call for unique solutions for sure, but most DIY types starting with a concrete slab are best off simply leaving it as is, and painting or staining it for appearance, or laying down a thin layer of wood or tile. For the most part, only commercial facilities with serious isolation problems (usually in cities), or with subways nearby, really need to worry about floating a floor. Having said all that, it is sometimes desirable to cut certain portions of a ground-level slab in order to reduce structure-born vibrations. And cutting a slab to lay in wiring pipes is far easier and cheaper than building a whole new floor system! But this should be done only after fully understanding the structural implications. There are other ways to run wires, after all.
Hope this is helpful...

--Wes

Posted: Mon Mar 10, 2003 6:50 am

Wes,

Great to see you here - welcome!

> Hope this is helpful <

Yes, thanks very much for the excellent post.

--Ethan

Posted: Mon Mar 10, 2003 8:23 am

Wes,
I am building a "room-within-a-room" for maximum isolation in my basement. I built the basement with extra high walls (10' from basement floor to ceiling floor joist of main floor) to accomodate this studio. I had figured that I needed a floating floor to get the most benefit out of the room-within-a-room structure.

In my situation would you recommend building a floating floor or not?

I also wanted to use the space under the floor for cabling runs. However, I am also concerned about the acoustical issues like booming bass and vibrations getting into the mic stands that you mentioned. I was planning on putting a thin floated concrete slap under the drum area.

Any advice would be greatly appreciated.
Thanks!
Scott

Posted: Mon Mar 10, 2003 9:07 am

I have built a room myself with a floating floor consisting of 2x4 beams on neopreen covered with soundboard, 3/4 ply, and particle board. Most of this was based on advice given to me from forums such as this one. I am not happy at all with the results. The soundproofing worked well over all but I now have bass resonances that will never be gotten rid of properly. I believe the loosely floating floor is allowing the entire structure to vibrate which in turn vibrates the outer structure as well. Like Wes said, unless awful vibrations/sound is getting in and/or you have neighbors underneath you, forget the floor. However, if you plan on doing drums, you will need a lot of isolation. 4 new walls and a ceiling decoupled from the original walls and at least 2 layers of 5/8" drywall on resilient channel. You'll probably also want soundboard behind the drywall.

What does everyone think of floating the new walls on neoprene? Soundproofing.org promotes that technique but of course they sell the stuff too.

Posted: Mon Mar 10, 2003 11:42 am

Scott and Josh,

I'll try to answer your two questions together since they're related: Scott, no, I would not float a wood-frame floor in your basement studio. There is no need for isolation in that direction. But it's great that you have 10'-0 to work with, so you have several options available to you. What you really need to float is your ceiling, in order to prevent studio sounds from disturbing those upstairs, and, perhaps more importantly, to attenuate the noise of the foot traffic above, so that you can use the house and the studio simultaneously. There are (at least) three ways to float, or isolate, the ceiling. In all three cases you should first apply 2 layers of gypsum to the existing overhead floor joists.

Scenario one: Build new, load-bearing walls (inside the existing walls) to carry new ceiling joists for the isolated ceiling. (And yes Josh, floating the walls on neoprene or the like will help isolate the new wall-ceiling system from the basement floor and the rest of the house.) Leave at least 1" airspace between the gypsum and the new joists. Then hang a couple of layers of gypsum from the new joists. Insulation will help some, but dollar for dollar, is not as important as the mass of the gypsum, and the fact that the two ceiling systems are not connected in any way. The disadvantage of this method is that the slab may not be able to withstand the new load-bearing walls without cracking.

Scenario two: Instead of bearing the load of the new ceiling on the walls, a commercial-type resilient ceiling grid is suspended from the existing overhead joists. This will result in isolation almost as good as scenario one, but transfers the load to the existing overhead joists. Be careful to calculate the effect of this new load; you don't want a sagging kitchen floor!

Both of the above methods will require that you give up some ceiling height.

Scenario three is the easiest and cheapest, and retains almost all of the ceiling height, but sacrifices some isolation. With this method, you screw resilient hat-channel directly through the gypsum and into the existing overhead joists, using long screws. Then more gypsum is hung from the resilient channel.

I don't know if you really need new walls for isolation purposes (you may not since it's a basement) so if you're on a really tight budget, scenario two or three would allow you to concentrate your resources more resourcefully .

Please note that since I am in the studio design business and must be careful about liability issues, I must make the disclaimer that this advice is offered purely for the purposes of discussion and education. Any actual construction should always involve professionals to assure safety, adherence to codes, etc.

Cheers,
Wes

Posted: Mon Mar 10, 2003 11:49 am

Hi Ethan,

Glad to see that you're moderating this forum. And I agree with the general consensus on your dynamite acoustics FAQ. Hey, I notice we'll be on the same panel at the TapeOp convention. What's the best way for me to contact you so we can make plans? Do you need my email address?

Wes

Posted: Mon Mar 10, 2003 12:03 pm

Wes,

> I notice we'll be on the same panel at the TapeOp convention. What's the best way for me to contact you so we can make plans? Do you need my email address? <

You can email me from my web site www.ethanwiner.com, and I'll get your email address from that.

I'm really looking forward to meeting a lot of you folks in person!

--Ethan

Posted: Mon Mar 10, 2003 2:38 pm

I thought the raised wood frame floors were generally filled w/ sand or some other damping material.

Would there still be bass resonance issues in the floor w/ such treatment?

Thanks,
Mike

Posted: Mon Mar 10, 2003 7:47 pm

Mike,

Sure, sand makes it a whole new ball game. It's heavy though; better be sure what's underneath can support it. And before you cover up the sand, crank up the bass and watch the patterns form so maybe we can clear up this large room/small room issue.
Brian Wilson liked sand in the control room.

--Wes

Posted: Tue Mar 11, 2003 3:13 am

Wow, great experts here.

Hi Wes, I'm really a little shocked that loating the floor could be a bad thing. At the moment I've floated my floor by using some 1,5" heavy foam with two layers of underlayment (= some sort of plywood, I'm from the Netherlands) and it works great.
As I will be building a new control and studio room in the future I'm also wondering whether or not to "start floating" which definitely is a hassle and if it can be avoided, great!

I guess an option would be to build a floating room (walls on neopren with ceiling joists on it) and see if the isolation works. Adding a floating floor like the one I mentioned above, can easily be put in atfterwards (like I did now). I guess if you're on a shared floor with any neighbours, you really have to float, don't you think so?

Greetings,
Dirk

Posted: Wed Mar 12, 2003 1:44 pm

Wes,
Thanks for your advice.
I had actually planned to use the scenario #1 that you described. Scenario #2 is attractive because it is cheaper, faster, and leaves more room width. I have considered this scenario also, but I have not found the "commercial-type resilient ceiling grid" that you mentioned (I have found only individual hangers). Can you direct me to a source for the resilient grid system?
I'm also concerned that scenario #2 might not provide enough isolation - my goal is to be able to have a "reasonably" loud rock/pop band be able to play while my family can still carry on a conversation upstairs. Is this a reasonable goal?

One more question - would it be a good solution to place a laminate wood floor system (like "Pergo") directly on the concrete? Do these types of floors have any negative impact on acoustics?

Thank you very much for your help,
Scott

Posted: Wed Mar 12, 2003 4:53 pm

Scott,

Check it out, you just saved a ton of money, right?

Quote:

Scenario #2 is attractive because it is cheaper, faster, and leaves more room width. I have considered this scenario also, but I have not found the "commercial-type resilient ceiling grid" that you mentioned (I have found only individual hangers). Can you direct me to a source for the resilient grid system?

The type of system I'm talking about is how they hang sheetrock ceilings in malls and such. You'd probably want to have it done professionally. No-one should ever hang anything overhead if they're not 1000 percent sure what they're doing. Here's how it works:

You screw eyebolts up into the joists, then hang standard heavy-gauge hanger wire from the eyebolts, as you would for a standard drop ceiling. The only wrinkle is that halfway down the hanger wire, you insert these isolation shocks from Mason Industries or some other supplier: http://www.mason-ind.com/

Then instead of running a T-grid system, you hang these heavy-duty 1 1/4" metal "C-joists" in one direction, and tie resilient channel to that in the other direction with tie-wire. Now you have a grid that you can hang 2 layers of drywall from, and it's almost as isolated as scenario one.

--Wes

Posted: Thu Mar 13, 2003 10:06 am

Wes,
Thank you very much for the information.
When you say "it's almost as isolated as scenario one", how close is it? Would you estimate that it's within 3dB?
Although scenario #2 would save money, the whole studio will not be worth anything if I can't enjoy it without upsetting the rest of the family.

Thanks again,
Scott

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