mineral wool floating floor construction and MSM calculation

[rod gervais]

Nikodemos,

you stated the folowing:

i was under the impression that if there is a continious underlayment under the concrete the load would spread equally on all surface...no?

anyway i was under the impression that with a reinforced concrete slab of 15cm the load of the walls would be insignificent.....

Your impressions are incorrect on both counts.

Concrete will flex under load - there is no way for you to take an edge load out of the equation with a 15cm slab. Although that gives you enough mass to lower the center frequency of the slab to a range suitable for music - it is not going to be rigid enough to do what you suggest - not unless it is a very small slab in area - and then still only if your wall loads are fairly balanced in weight (which is not suggested by your sketches).

a thicker slab could perhaps (with the right reinforcing design) be designed to do what you suggest - but the engineering and construction costs would not make it worth the while.......

On another note- your details introduce a perfect flanking path back into structure.......

While hanging the ceiling is acceptable (I would rathr see the inner walls carry the load and comlpetely decouple them from the structure) the walls should stop at the ceiling...........

Connecting them to the floor above is your weak point - this from 2 perspectives - one the connection to the outside structure you're tring to isolate yourself from - and the other being the possible lowering of TL values due to the 3rd leaf you introduce into the equation.

Let them end at the top of the inner ceiling framing - and then you can use either isolating lateral braces tied to the structure above for seismic bracing - or do the same off of the adjacent walls that do tie to the structure.

Diagonal bracing consisting of (either) an iso-spring or neoprene iso hanger can serve as a very effective bace for the inner structure - as can the WIC clips manufactured by Mason Industries that would attach to the adjacent wall assembly.

Either way - this is your best construction method to acheive maximum isolation with your assembly.

Please describe in more depth your wall assembly - it would be a shame to have walls that did not equal the isolating capabilities inherant in your slab when all was said and done.

Sincerely,

Rod

[Nikodemos]

mr.Desart

Piano is gypsumboard from Knauf with higher density (10,7kg/m2 for the 12,5mm board instead 9kg/m2 of their average boards)

mr.Gervais
first of all thanks for checking this thread
i was afraid that most of my conclusions were wrong
however my question is: if i must go for a mineral wool - concrete floating floor(that is if i don't make it with the syllomer and equals) what should i do regarding the walls load matter? should i put on the perimeter of the room more dense wool? and how could calculate how dense and how wide? I'm not trying to get advices for free here, believe me, but i've talked to some "profesionall acousticians" here in Greece and they didn't have a clue what we were talking about.....so i feel a bit lost
Regarding my wall plan and especially the inner wall - inner ceiling joint i've been asking this very same question(with a drawning) in this forum
http://www.johnlsayers.com/phpBB2/viewt ... c&start=30
but unfortunatelly i didn't come up with an answer.....i do think that this is not the best approach to do it regarding TL but:
i talked to quite a few drywall technicians and nobody had experience on such a structure....that's not a good thing!! Also i found this aproach on Everest's books....and i was really concerned about the liability of such a structure regarding it's stability...you see i don't have your knowledge and experience and as far as i can say greek drywall technicians don't have a clue neither....
Of course i'll take your word on it....i have your book, but i couldn't find something on this(or i've missed it
) because i think your book aims mostly to full drywall assemblies and not to concrete buildings...and i, probably due to lack of knowledge, couldn't transcribe things to match my situation.
I would be greatfull if you could get in some details on "how to do it"

Now some info on my wall plan:
on the outter side of the studio
25cm reinforced concrete - 10cm of cavity filled with 30kg/m3 glass wool - 3 layers of 12,5mm drywall(knauf piano 10,7kg/m2) on 100mm steel studs filled again with glass wool.
on the inner side(between rooms):
3 layers of 12,5mm drywall(knauf piano 10,7kg/m2) on 100mm steel studs filled with glass wool - 10cm cavity filled with 30kg/m3 glass wool - 3 layers of 12,5mm drywall(knauf piano 10,7kg/m2) on 100mm steel studs filled again with glass wool.
I'm also thinking of putting a layer of grrenglue between 1st and 2nd layer of drywall everywhere and probably to add another layer of gypsumboard in the main recording room's inner wall in order to get different masses on walls and smooth out the resonanse freqencies between walls. Finally on the inner wall of the practice room i plan to add a 3mm layer of lead between 2nd and 3rd layer of gypsum board to add even more mass with minimum space loss.
I attached my initial wall plan
Nikodemos

[rod gervais]

I would attack the design like this:





Rod

[Nikodemos]

Mr.Gervais
First of all thanks for your help and interest
i'm going to meet with an engineer friend of mine who's helping me with the project and show him your approach. I have some initial questions:
would it be possible to use this way of decoupling you describe fot the wall - floor joint, for the wall - ceiling joint? In my basement the height is 3,45 m but there are some points (i think it's joists the right word? ) where the height is 2,90m. I f i get it right from your plan with this way the height of the inner ceiling is defined by the minimum outter ceiling height (3,45m)right?
I was wonderng if there is a way to build the walls all the way to the concrete ceiling and decouple them from it the way you describe the decoupling from the floor. Can these decoupling braces be used in a ceiling - wall joint or they work only under load? I underastand that your approach is the correct one and why this happens but i am concerned about the height. With your design is there a way for the inner ceiling to follow the concrete ceiling height?
and another question: when you say 3 leaf in my plan you mean the inner ceiling and the 2 walls? if theoritically i could perfectly decouple the walls from the ceiling in my plan would that 3 leaf effect be important?
thanks again for your help and your advices

Mr.Desart
I've spent the last 3 days researching mineral wool in Greece regarding properties, availability, brands etc. and i REALLY understood what you describe in your studiotips "thoughts on minerall wool" post.....In every country the same brand has completely different products with different specs making the research for a suitable product probably impossible....Here in Greece glass wool is not the first choice in building insullation so there are not too much choices in brands and types in the market plus tha availability is questionable. Also for such a small project as mine (compared to the construction industry) the supliers seem to be quite unwilling to provide info and specs(even unfriendly sometimes!!!)
On the other hand i there is lots of rock wool products manufactered here in Greece with their specs available. I looked in the isover link and compared the info on impact and airborne noise reduction regarding thickness, dynamic stiffnes etc to Geollan 100kg/m3 rock wool panels and it looks as it could be a product that could fitt in....what do you think about that? i mean rock wool in general
Also could you tell me what you think about my inner wall plan.....
thanks A LOT!!!

Nikodemos

[Eric_Desart]

Nikodemos,

I had no time yet going more in-depth.
You got a nice suggestion from Rod already.

About the differences in rockwool and fibreglass. You read right.
There is the difference in geographical raw materials (minerals), the different things they mix it with to make these melted minerals optimal spinnable, binding additives, production method, etc.

But: when using the stuff for absorption, it all doesn't matter that much (taking into account that rockwool by thicker fibre is mostly denser/heavier for same functionality), but when using the dynamic stiffness, elasticity and compressibility it becomes more important.

I had a discussion with Rockwool here, and have measurement data in function of dynamic stiffness from WTCB (national Building research institute).
In theory it works as good as fibreglass, but since the fiber of rockwool (as I know it) is more brittle, the producer does not allow the same deflection under load than fibreglass with the same dynamic stiffness.
I think in general fiberglass is more elastic, which in in favour for floating floor principles in function of higher allowed deflection.

Hence my experience and research tells me that rockwool while used a lot for floating floors and resilient skins (floating walls), they are applied within standard building frequency ranges.
They do not allow enough deflection in % of the material thickness in function of degeneration of the fibers.

Hence as I know it here, Rockwool floating floors are not ideal for very low resonance floating floors (studio applications).

Fiberglass is more elastic and seems to allow higher deflection rates and still guarantee long-time behavior.
That makes fiberglass a better material for this type of studio applications.

I'm rather sure (my belly), that your idea of fiberglass calculated on the normal load, with high denser fiberglass at the edges to compensate for the wall weight IS possible.
But this stuff is badly documented for these purposes, and even if I should calculate this for Isover boards here, in how far can this be translated to whatever boards you buy there, EVEN WHEN THEY ARE FROM THE SAME BRAND?

In order to make standard building stuff commercially attractive they produce in different factories to cover local regions. They even buy existing (former competing) factories with there own raw material sources and production methods to expand their teritory.
Rockwool boards in Belgium are somewhat different from these in Germany, as well in code as well in how they look and feel.

To summarize: for floating floors with studio-low MSM frequencies I should NOT resourt to Rockwool as I know rockwool.

I think with fiberglas it should be worth investigating, even for an application with walls at the edges as you drafted it (adjusting densities). But that cost time, cooperation with the producers to get data, they likely have but don't publish, etc., and I certainly should not guarantee one could copy this exactly for boards from other factories.

Density and stiffness are not always nicely related, but are a combination of fibers, the added chemicals, and the binding process.
There are rockwool and fiberglass blankets +/- 90 to 120 kg/m3 feeling really soft as a blanket. That's because there (almost) aren't binders in it, therefore the wool is even stitched with metal wire on chicken wire to keep it in place.
A 70 kg/m3 base rockwool board used as base for ceiling tiles (self carrying) feels/looks quite different (more stable/tight) than a standard 70 kg/m3 board used for thermal applications.
I have a couple of OC 703 and OC 705 here, and they feel different from the corresponding Isover boards I know.

The safest manner is still to use material as intended and guaranteed by the producer. Therefore all these more technical vibration brands exist.

[Nikodemos]

well, i still haven't been able to contact the sylomer dealers here in Greece and that's probably normal since the last 7 days the whole country has beev on fire with dozens of people killed and whole villages burnt to the ground .....at the same time we are 2 weeks before the national ellections and so nothings seems to work in these country.....The problem is that time is running......so the minerall wool scenario seems to be the leading one in my case....
Mr.Desart my next question is probably stupid and tottaly anti-scientific (and it couldn't be different since i'm the one who's asking ):
How dissfunctional would be in my "real world" situation (my studio is based in the basement of a building with an unused parking space above on ground level and with no other buildings attached to it) a minerall wool - concrete floating floor built as calculated as possible but certainly not reaching the low MSM frequency of a proper acoustical floating floor? I mean my concerns are sound travelling through rooms and mainly impact noise and vibrations(i guess) reaching the appartments on the first floor 7m above my floor.....can the sound passing through this MSM system even at these lower resonance frequences trigger such a big mass as the existing concrete structure to vibrate and transmit the sound to that distance? even if they are decoupled (with the minerall wool) from the sound source?...and if so the tranmitted to the 1st floor would be loud enough to be annoying? (i mean to the usuall rood, anti-musician old couple that lives on the first floor above every basement studio )
Nine years ago we built a practice room in this same basement and i see it now we did everything wrong 3 leaf walls, terrible doors etc plus a minerall wool concrete floor....as i can remember it was 7cm of reinforced concrete on top of 10cm mineral wool(i don't remember if it was fiberglass or rockwool or even th dencity...i just remember it was hard )
we didn't know anything about calculations or MSM freq or anything.....just some friend told us "do that" The thing is that even right outside the room door the TL was not high enough (mainly through the door) the TL between rooms was acceptable and most important there was no sound on the first floor....an there was lots of noise there before the floor!!!I know that this floor is not working correctly and that it probably won't last but.....my point is this: could a floting floor of this kind
(kind of "domestic") but calculated as much as possible to fit the current acoustical and structural needs(walls load etc) be a wiining scenario for my situation?
I hope i don't sound stupid or rude

Nikodemos

[Eric_Desart]

....... here in Greece and that's probably normal since the last 7 days the whole country has beev on fire with dozens of people killed and whole villages burnt to the ground .....at the same time we are 2 weeks before the national ellections and so nothings seems to work in these country.....The problem is that time is running......so the minerall wool scenario seems to be the leading one in my case....
...........
I hope i don't sound stupid or rude

No you don't sound stupid or rude, just very stubborn in a fun manner.

Nikodemus,

I don't feel safe with rockwool in that situation. Hence I'm not going to advice it, and no I'm not going to guess.
You can go to rockwool with 10 cm and follow Rods advice building your walls not on the floating floor.
Otherwise don't use rockwool for that floor.

The thickness here of 100 mm will make up for the lower deflection rate.

Now you can rephrase your question in another manner, but this is as far as I go.

I know about these fires, and it's disastrous. I really do feel with you and these people. And if it's true that these fires are somehow or partly related with guys wanting to use that land for development stuff, they should hang them all on the highest trees (that related land development law of yours).

And about elections:
We had them 6 to 7 weeks back. Belgium was never so divided between our regions. After 6/7 weeks of intense discussions (day/night) on all levels we are as far as the first hour after the election. And at this moment nobody has any idea how to overcome or compromise related real in-depth principle differences.
(different cultures related to different languages and economical strength).

[Nikodemos]

Mr.Desart i promise i will not ask another question on the "floor" subject.....until i'll have something usefull to say or show anyway

thanks for everything

Nikodemos

[rod gervais]

Mr.Desart i promise i will not ask another question on the "floor" subject.....until i'll have something usefull to say or show anyway

Nikodemos,

one of the real problems with using eithe rthe fiberglass or rockwool for the walls is that the loadings can vary tremendously along the wall.

For example - a wall 8' in height constructed with 2x4 framing and 2 layers of 5/8" drywall will weight about 6 psf - or about 48 plf (per linear foot).

So you caclulate the required density of fiberglass you need to carry that load while meeting the required compression ratios and then you suddenly come to a place where you have a door opening - and you have a point load on the hinge side of about 300 pounds (if you build my super door) and then 1/2 of the header weight - and you can't makre it from A to B with the material you are using............ but you also can't start using small pieces here and there.

That's why you really need to look at this very caefully.

I actually develop wall elevations with all openings and showing individual studs and calculate for each and every load point individually - especially with rooms that are not rectangular in shape - thus the ceiling load is ever changing,,,,,,,,,,,,,,,

I hope this helps you to understand

Rod

[sharward]

I remember going through this type of exercise when coming up with my first few floating floor designs, using EPDM rubber pucks as the proposed elastomer. I even purchased a sheet of 1/2" thick EPDM for the purpose and paid a machine shop to conduct some tests on a sample puck to determine its deflection under varying loads.

I probably spent months going back and forth with various ideas before finally coming to a conclusion that it wasn't going to work for me, especially in my state where the propensity of earthquakes in some areas (not really mine, thankfully) have had a significant impact on building code strictness. Even if I had come up with a method of calculating all my point loads perfectly, I'm convinced it would not have passed my local building department's initial plan check process.

I'm not trying to hijack the thread here, as I've "moved on" and am quite pleased with having done so -- my point is that the process is, as you're finding, very complicated. You seem to have an appreciation for that.

[Nikodemos]

well, maybe i am a "over - complicating things" freak

mr.Desart
i found this www.vibro.gr here in Greece. They manufacture anti-vibration mounds, pads , hangers etc. They have neoprene and rubber pads for floating floors....perhaps,if you have some time, could take a look and tell me what you think.

Thanks
Nikodemos

[Eric_Desart]

....... here in Greece and that's probably normal since the last 7 days the whole country has beev on fire with dozens of people killed and whole villages burnt to the ground .....at the same time we are 2 weeks before the national ellections and so nothings seems to work in these country.....The problem is that time is running......so the minerall wool scenario seems to be the leading one in my case....
...........
I hope i don't sound stupid or rude

No you don't sound stupid or rude, just very stubborn in a fun manner.

Nikodemus,

I don't feel safe with rockwool in that situation. Hence I'm not going to advice it, and no I'm not going to guess.
You can go to rockwool with 10 cm and follow Rods advice building your walls not on the floating floor.
Otherwise don't use rockwool for that floor.

The thickness here of 100 mm will make up for the lower deflection rate.

Now you can rephrase your question in another manner, but this is as far as I go.

I know about these fires, and it's disastrous. I really do feel with you and these people. And if it's true that these fires are somehow or partly related with guys wanting to use that land for development stuff, they should hang them all on the highest trees (that related land development law of yours).

And about elections:
We had them bit less than 3 months back. Belgium was never so divided between our regions. After exact 81 days (just heard on TV) of intense discussions (day/night) on all levels we are as far as the first day after the election. And at this moment nobody has any idea how to overcome or compromise related real in-depth principle differences.
(different cultures related to different languages and economical strength).

Edited exact election/discussion periods ..

[rod gervais]

well, maybe i am a "over - complicating things" freak

mr.Desart
i found this www.vibro.gr here in Greece. They manufacture anti-vibration mounds, pads , hangers etc. They have neoprene and rubber pads for floating floors....perhaps,if you have some time, could take a look and tell me what you think.

Nikodemos,

Although I am not my friend Eric - I hope you don't mind my responding to this.

Mason Industries (whose materials are in my details) produces a very similar isolator to what I see in that company's literature - BUT - with a much wider range of weight capacities - and I know their products - have been using them for years......... The company you point ot may have great productsd or not - I do not know _ i have neever seen or used their products....... so I can't recommend them.

Mason Industires has a sales force for Greece.

The product I would specify for your walls is found here:

http://209.200.80.33/html/SUBMITTALS/NE ... d-26-1.pdf

For the ceiling here (Model HD)

http://www.mason-ind.com/html/hangers_p ... s_list.htm

the contact information for Greece is:

Rep Name: Mason Industries
Contact Name: Steve Fey
Address: 350 Rabro Dr Hauppauge New York 11788 United States
Telephone: (631) 348-0282
Fax: (631) 348-0279
E-Mail: sfey@mason-ind.com
Website: www.mason-ind.com

Sincerely,

Rod

[Nikodemos]

Rod (i hope it's ok to call you Rod..)
I'm greatfull for the fact that real experts take the time to help...especially you and Eric

well, i sent an email to Mason....
2 questions:
in your plan the drywall rests on the existing slab....if i go this way should i pour the concrete on the floating floor prior to bulding the wall or vice versa?
I was told that it's not a good idea to put drywall in a place where wet concrete is and that is better to wait till the concrete is fully dry, about 25 days to avoid moisture affecting the gypsumboards...
the second one
How important is "3 leaf" in a floor situation....i mean if a built a concrete mineral wool floating floor and on top put a wooden floor on 4cm wood joist(right word?) would this create a 3 leaf system and how bad it could be?

thanks
Nikodemos

[rod gervais]

in your plan the drywall rests on the existing slab....if i go this way should i pour the concrete on the floating floor prior to bulding the wall or vice versa?

1st - the drywall never sits right on the floor - if you look at the detail it notes that you install acker rod and caulk in that location - si it's 1/4 to 3/8" AFF.

I was told that it's not a good idea to put drywall in a place where wet concrete is and that is better to wait till the concrete is fully dry, about 25 days to avoid moisture affecting the gypsumboards...

It really isn't in general - so you will want to take care to place some plastic sheeting againsg the weall - lap it well onto the floor and tape it down real good before you put doiwn your fibergass and get ready to get to pouring your concrete slab.

The bottom ilne is that the wall wants to finish off toa caulk seal at floor level - which means it goes in prior to the concrete.

the second one
How important is "3 leaf" in a floor situation....i mean if a built a concrete mineral wool floating floor and on top put a wooden floor on 4cm wood joist(right word?) would this create a 3 leaf system and how bad it could be?

What in the world would possess you to want to do that???????????????