John Sayers' Recording Studio Design Forum Archive

If I wanted to "float" a floor, lets say for my control room, what material is considered 'the norm' for the actual flooring. Should I use Homasote, as its supposed to prevent less mechanical vibration than regular sheetrock, or should I not waste time with Homasote and just use regular plywood?

Also, to kill two bird with one stone, I might as well ask this now.... what do those who have relevant experience think of Homasote?? Considering its about 2 - 2.5 times the price of a piece of 5/8th drywall, is it really worth using... and aisde from the issue of is it "worth" it,.... is it really considered technically superior.... (i.e. or is it considered just another manufacturer gimmick that managed to stick around for a long time.)

1/2" EPDM rubber that's 60 durometer. I am having mine cut into length (from this company 48") by 2" wide strips. From there I will cut them in to smaller pieces.

2 companies I have been talking to are:

F.B. Wright Co. contact is Bev Phillips" bevp@fbw-cincy.com and my 45"x2"x1/2" are $9.56 each

the other company is Allstate Gasket Company http://www.allstategasket.com

The EPDM will be nailed with a slight compression to the 2"X4" flooring joists and then place insulation like Rockwool (Roxul) in between the joists. Then you would place your first layer of subfloor, preferablly tounge and groove that you caulk ALL the seams with an acoustical sealant caulk. Another layer of subfloor is recommended also, running in another direction so the seams don't overlap.

Carl, glad you said that BEFORE you started; I wouldn't recommend nailing your EPDM to the joists, even with a slight compression; two things this will do - one, after a time when the rubber relaxes from the weight, you will likely get a few "shorts" in your resilient mounts from the nails - also, rubber needs to be free to "squish", or it changes the elasticity (and ruins whatever calculations you've done.

I would just glue it on with the cement recommended by the manufacturer instead... Steve

Steve,

BEFORE, I go any further cause I am planning on putting the floors in within a few weeks, PLEASE clarify everything for me here. I am getting frustrated here. First I was told to get neoprene and nail it, then told the neoprene only lasts a few years and get the EPDM instead. Would you PLEASE explain EXACTLY what I am supposed to get and how it is supposed to be mounted and used and what you mean by calculations before I really screw things up here?

Nemesys: I appologize if I had given you any false info here, apparently everything I was told is not fully true, just tried to help.

Carl, pardon the intrusion, just trying to help:
- EPDM is THE material, no competition – confirmed with the rubber specialist. 60 or 70 duro (shore) hardness is just fine.
- Most definitely do NOT nail the rubber strips to the joists.
o First, you are running a significant risk of later ‘shorts’ as Steve said,
o Second, it is overkill. I would suggest that you just use the cable ties (locking strips?) to hold the rubber strips in place before you turn the joists upside down. Once you have the whole construction weight on top of it, there is no way of EPDM escaping. Or, if you do indeed have the long lasting rubber-to-wood sort of cement (glue) available, sure, that’s safer than anything. I could not find anything like that around here (South Africa).
All the best,
Mihajlo

Carl,

I used Liquid Nails construction adhesive to attach the rubber. It's working just fine.



Aaron

Carl, on page two of the "complete section" sticky, I did state that you could use screws to mount EPDM, but then said it would be better if you were to use contact cement. It was Bryan who said he'd used screws on his floor.

This part - "2"X4" flooring joists and then place insulation like Rockwool (Roxul) in between the joists. Then you would place your first layer of subfloor, preferablly tounge and groove that you caulk ALL the seams with an acoustical sealant caulk. Another layer of subfloor is recommended also, running in another direction so the seams don't overlap." - you've got correct; the spacing of your pucks will depend on how wide they are, whether you're building your walls on top of the floated floor, and the total estimated weight of the whole floated assembly - if the walls will be on top of the floor, then you'll need closer puck spacing around the perimeter to support the extra weight. Across the main floor area, 2" wide by 2" long pucks spaced 5 feet apart will work well. If your walls are resting on the floor, I would put pucks under every joist under the wall, and every 2 feet along the rim joists.

Completely fill the cavities with rockwool, and unless it ends up slightly higher than the joists I would add strips of unfaced fiberglass insulation down the center of each joist cavity so they will press up on the flooring; you don't need this ringing.

If you have any moisture problems whatever, you need to fix those before even considering laying a floated floor.

I'm sorry you're getting so frustrated; I try not to let incorrect things through, but sometimes it happens. Please keep in mind that I contribute somewhere close to 1000 hours of my time (free) per year to this site alone, and I also tend to get frustrated by the lack of progress on my own projects partially because I do this. If I were to bill all that time, it would amount to $120,000 per year.

I've considered doing some sort of all-in-one guide for building a studio, but with the current Internet attitude that everything is supposed to be free, where's the incentive? I already spend 3 times as much time here as I should, so it's hard to throw even more (unavailable) time at it. All this gets me (besides occasional thanks) is even less likelihood that I'll have my own studio built in the next 5 years.

Sorry for the rant, I'm too tired after 12-hour graveyard shifts to always "play nice" - if I didn't answer all your questions, let me know and I'll try to catch the rest... Steve

cfuehrer wrote:Steve,

BEFORE, I go any further cause I am planning on putting the floors in within a few weeks, PLEASE clarify everything for me here. I am getting frustrated here. First I was told to get neoprene and nail it, then told the neoprene only lasts a few years and get the EPDM instead. Would you PLEASE explain EXACTLY what I am supposed to get and how it is supposed to be mounted and used and what you mean by calculations before I really screw things up here?

Nemesys: I appologize if I had given you any false info here, apparently everything I was told is not fully true, just tried to help.

Greetings

if your using Elastomers to float floors trhen you need to calculate thigns properly, otherwise you run the risk of making things worse, rather than better.

Read my post here http://www.johnlsayers.com/phpBB2/viewt ... &start=270

I gave a link in that post to a website that shows you how to calculate the correct size of rubber blocks for the load you intend to put on them.

As Steve rightly says, you SHOULD use the correct adhesive that the rubber manufacturer recommends. Do NOT guess with adhesives for applications like this.

If you want to see a floating floor being constructed see my Studio Build Diary... http://forum.studiotips.com/viewforum.php?f=1

mmutavdzic is incorrect. EPDM is NOT the only Elatomer suitable. Sylomer is a very high quality Elastomer used for vobratiobn mounts. And the EAR products also work well too.




Hope that helps


PAul

Paul,
I am sure you must be right, but, considering the price/performance/longevity ratios, EPDM wins according to what I have seen on this forum?

On the other hand, if the price is not an issue, we would all go for the oil-filled rubber absorbers (engine mounts).

Regards,
Mihajlo

Paul Woodlock wrote:

cfuehrer wrote:Steve,

mmutavdzic is incorrect. EPDM is NOT the only Elatomer suitable. Sylomer is a very high quality Elastomer used for vobratiobn mounts. And the EAR products also work well too.

PAul

mmutavdzic wrote:Paul,
I am sure you must be right, but, considering the price/performance/longevity ratios, EPDM wins according to what I have seen on this forum?

On the other hand, if the price is not an issue, we would all go for the oil-filled rubber absorbers (engine mounts).

Regards,
Mihajlo

Paul Woodlock wrote:

cfuehrer wrote:Steve,

mmutavdzic is incorrect. EPDM is NOT the only Elatomer suitable. Sylomer is a very high quality Elastomer used for vobratiobn mounts. And the EAR products also work well too.

PAul

Greetings Mihajlo

I just wanted to make aware to folks here of alternatives. I'm not saying EPDM is no good either, but you can't really make a blanket statement that EPDM wins hands down, especially when the only evidence is the writings in a forum.

The other factor to consider is location. Not everyone can get hold of certain materials without expensive importation, and especially when the local material is just as good.

Also , you cannot recommend a certain grade ( durometer value ) for an application without knowing exact loads and other parameters ( including cost per grade ) involved.

Neither can you work on the amount of % deflection of the rubber to get a correct design. It's far more complicated than that.

Furthermore durometer reading only tells you the hardness of an elastomer when NOT subjected to load.

The hardness of an elastomer ( i.e it's modulus of elasticity ) CHANGES with Load, Temperature, Time, and the shape of the Elastomer block being used.

To calculate a floating floor properly, you need the specifications of your intended Elastomer. These specs will include nomographs of the modulus of elasticity against time temp and load.

And all these parameters influence each other.

For example. the higher the load the less time the Elastomer will keep it's original spec. But this is NOT a linear or fully exponential curve. IN other words it can't be expressed easily, and probably not at all via a formula. There's a kind of 'breakpoint' where below it, you can increase the load without shortening the lifespan hardly at all, then above this 'breakpoint, even a fairly small increase in load can shroten the lifespan from years to months, or in extreme cases...Days.

The reason the lifespan is shortened is because with high loads the modulus of elasticity changes for the worse, and your floating floor not only becomes useless, if it's resonant freqeuncy ends up at a critical frequency in the audio band, it can make things worse than not having a floating floor at all.

The shape of the blocks themselves also make a profound difference to the resonant freqeuncy of the system. This is called the Shape factor, and is also different for different kinds of Elastomer.

You know, over the last few years I've read hundreds of forum threads were people are either designing or have built a floating floor ( Mostly out of wood ), and I would say 98% of them have been done without ANY proper calculation.

Usually becuase someone else ( Even people who write magazine articles!! ) advising them doesn't know how to calculate them, or simply is naive that calculations are needed in the first place.

For all: A floating floor is a mass-spring-mass system. And as such has a resonant frequency. At this resonant freqeuncy you don't get isolation, in fact you get the reverse...amplification. The amount of amplification depends upon how damped the elastomer is.

Anyone whose ever driven a car where the shock absorbers have given up the ghost, will know painfully the effects of amplification at resonance as their car bounces wildly down the road.

To avoid the floating floor making things worse the resonant ( or 'natural', as you'll sometimes see it described ) freqeuncy must be calculated to be BELOW the audible freqeuncy range. Or at least below the lowest freqeuncy your monitors can reproduce.


Lastly I don't see much point in a wooden floating floor for these reasons...


1] Unless your using a very soft elastomer, I cannot see how a low enough resonant freqeuncy can be achieved. You need lots of mass ( large load ) to get a low natural freqeuncy. Plus you need a largish airgap.

A 4" (100mm) or 5"(125mm) steel reinforced slab, with at least a 1" (25mm), and preferably 2" (50mm) airgap and block height ) will get you where you wanna be.

2] A wooden floated floor is effectively a huge drumskin. So floating a wooden floating floor,even if you do calculate a low enough natural frequency, can severely affect the acoustics of the room.

3] A floating floor is really the LAST Line of defence in Soundproofing. In other words, UNLESS the rest of the soundproofing is of a VERY HIGH Isolation value, there is little point in floating the floor at all.


Floating Floors ( a floating anything ) without calculation, or when it's actually unecessary to float a floor is very likely to waste lots of time, effort and money.

Hope that helps

Paul

Usually becuase someone else ( Even people who write magazine articles!! ) advising them doesn't know how to calculate them, or simply is naive that calculations are needed in the first place.

Amen!

There are many parts of building a studio that may just be "constructed" for good results, but floating floors are an area that requires design and "engineering". This is forgotten all too often.

Not too forgetfully
Andre

If you don't want to quite become a vibration/isolation engineer, but still want good results, you should spend a bit more $$ and use a company like Kinetics or Mason Industries, or EAR as Paul has done; here's a couple links I've had bookmarked for years but don't remember posting -

http://www.mason-ind.com/floating_floor ... ilings.htm

http://www.mason-ind.com/architect_engin_index.htm

http://www.mason-ind.com/eafm_mounts.htm

Note the actual specs on this last page, that will help you with your floor design - you still need to know all the material weights, etc, but talking to one of these guys on email or phone would be very wise IMO... Steve

.

Lastly I don't see much point in a wooden floating floor for these reasons...

So, let me see if I understand this correctly. IF a floating concrete floor is REALLY the only way to do this and have it work the way it is suppose to........AND hire a consulting firm to get it right in the first place......WHERE DID I TAKE A WRONG TURN HERE!!....

What this really says to the HOME STUDIO builder who is NOT BILL GATES
is..........FORGET IT!!! Well now, after reading this, somewhere along the line, folks like me who would LIKE to build this stuff, but can't afford FLOATING CONCRETE FLOORS, or $2k monitors, will now GIVE UP this home studio idea all together since it SOUNDS as if all home cooked ideas and even years of reading "how to DIY" are now a total waste of time.
I guess it's the same ole thing. I should have listened to my wife years ago. Boy, that snake oil tastes like crap

There should be a heading here that states.....UNLESS YOU HAVE A BIG BUDGET>>PROCEED AT YOUR OWN RISK!!!
Oh, BTW, better inform the people in the DESIGN FORUM of this development. I'd be PISSED if I spent all the time and money to build stuff the way it has come down here and then not have it work. Well, thats it for me. I can't afford this club. Adios

Rick, remember the sand-filled "sand box" we talked about? Remember the joists and EPDM pads UNDER the sand'filled box? Poor man's version... you got large air/insulation cavity, which lowers mam; you got high mass in the sand box, which lowers mam; you still got wood, which is affordable (sorta) for the framing; and you got sand, which can be carried in in a bucket a little at a time if necessary, and screeded off once the box is full...

It's up to YOU to keep your CAT from figuring out what ELSE this could be used for, til you get the top on it...

Also keep in mind that dozens of our members have done various floated floors that did NOT follow all these "rules", and not one problem reported.

While it's true that the "bunker" Paul is building is going to be a "Little Galaxy", this does NOT mean that perfect is the ONLY way to build; At last count, Paul had something like 6 or 7 layers of gypsum on ONE LEAF in his studio build; he also claims to like ear-splitting volume at wee hours of the morning, without disturbing "woman" - under all those conditions, his plan is probably only 20% overkill

I am in no way knocking Paul's efforts; he has done TONS of research and knows what he wants out of his studio, and intends to make it at LEAST as good as he wants it to be; by the same token, this does NOT mean that this is the ONLY way to build, or the only level of sound isolation that will work for OTHERS.

If you don't believe me, think back to HR's thread by "amped", last year - here's a quote from page four of that thread, regarding a NON-concrete floated floor, free-standing 20 x 24 building set on pier blocks in Austin Texas -

Quote "Finlly finished, exactly three months to the day. This room is nothing sort of absolutley infreekincredible! Almost zero audible sound at ten feet. The week link is definately the door, Ill be installing a 1-3/4" solid core door asap. The sound on the inside is very workable, with only the carpet down, it has a warm, rich ambient texture that in my opinion will be reatively simple to tune. So, to sum it up, Im very pleased with the outcome of this project and woud like to thank everyone who offered input along the line, especially knightfly (yeah you Steve) for taking the time to work with me to get the job done correctly the first time. Uhh, whats your opinion on the Tascam portastudio 788?
Beer time,
Later"

Basically, this was double OSB outside, double 5/8 gypsum on RC inside, double 3/4 OSB bottom leaf, triple 3/4 OSB with 90 lb roofing between for upper floor leaf, 1/2" neoprene pucks, 2x6 joists between the floor leaves, slightly compressed insulation fill between floor leaves, and ceiling construction to match the walls. Door was NOT sound locked.

Oh, did I mention that these guys are a METAL band with double bass drum kit??!?

Now, what was that about concrete being the ONLY way? Steve

Hello Steve.........WHEW!! Ok, gottcha. Sorry for the freakout! You know me......one little pebble in the road and it's bump city. Well, I guess it's one persons opinion, not fact that concrete is the ONLY thing that works. Ok, I'll buy that. As far as calculating the weight/pad thing, I don't know. That IS going to be tough. Don't need to think about it at the moment though. My friends won't be doing much untill after winter, so that gives me LOTS of rainy days to figure it out. Thanks again Steve. Your positive advice keeps me interested again. Have a great week.
Rick