mineral wool floating floor construction and MSM calculation

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

Nikodemos wrote:

....... 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 :cry: :x :cry: .....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 :D

:mrgreen: 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). :twisted: 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 ..

Nikodemos wrote:

well, maybe i am a "over - complicating things" freak :D 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: [removed] Hauppauge New York 11788 United States Telephone: [removed] Fax: [removed] E-Mail: [removed] Website: www.mason-ind.com Sincerely, Rod

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 :D 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 :shock: 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

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 :shock: 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???????????????

well when i said "rests on the floor" i meant the construction you described. about the floor, i maybe don'y know how to describe it....i mean a wooden parqeut finish...i know that there are some that are aplied directly on the slab with adhesive or panels attached to each other and some nailed on wood joists (at least that's what happens here...)....i didn't mean building a floating wooden deck on top of a floating concrete floor.....or at least i didn't want to say so :D anyway, thanks once again for your advises and guidelines....you're really helpfull. Nikodemos

Nikodemos, OK - that makes more sense - I have no problem with the installation of a wood (parquet or not) floor over the concrete - I don't even suppose i would with wod slats as long as the vavity was completely filled with rockwool to the point that it completly damped the wood I would not want (and this has nothing to do with 3 leaf BTW) the wood to be able to vibrate freely...... Rod

in order to make this thread more spicey and colourfull i uploaded some pics of my space :D as i said this is a concrete basement 2/3 underground with 3,50m height and with an area of about 220m2. I have "drawn" some shape lines on the floor Nikodemos

Nikodemos wrote:

in order to make this thread more spicey and colourfull i uploaded some pics of my space :D as i said this is a concrete basement 2/3 underground with 3,50m height and with an area of about 220m2. I have "drawn" some shape lines on the floor Nikodemos

:twisted: That's not making the thread spicey, that's making people jealous. (or are that synonyms?)

well, actually i must admit i used photoshop to remove the flloded water, rats,snakes and the other usual habitants of this "hole" :D :D :D :D .....but i think the space has potentials still researching on the floor options..... i hope it's ok to keep this thread as my "construction" thread and a couple of my usual questions :shock: How "wrong" it would be to lift the walls all the way to the existing ceiling, as in Everest's books, using some kind of anti vibration mounts-pads ot reduce the transmission of vibrations to the concrete ceiling? I ask because this would allow me to use as much height as possible. I would like to have pipes under the floating floors for audio wiring between rooms.....if i build the walls on the existing slab and not on the floating floor then i'll have to open holes in these walls in order to pass the pipes through.....how bad that would be? thanks Nikodemos

Nikodemos wrote:

How "wrong" it would be to lift the walls all the way to the existing ceiling, as in Everest's books, using some kind of anti vibration mounts-pads ot reduce the transmission of vibrations to the concrete ceiling? I ask because this would allow me to use as much height as possible.

It would be exactly the same height available with the ceiling joist resting on the walls or supported completely by the ceiling - one is not driving the other - if your walls are framed perpendicular to the existingf beams/jiosts - then there would be no problem adjusting your wall heights to follow the contour of the existing ceiling. I will provide you with a details for a sidewall brace that you can use instead of the baces at the ceiling - and you still maintain maximum isolation from the existing structure.....

I would like to have pipes under the floating floors for audio wiring between rooms.....if i build the walls on the existing slab and not on the floating floor then i'll have to open holes in these walls in order to pass the pipes through.....how bad that would be?

It wouldn't be a big deal - just be as neat as you can - after all - you're going to also penetrate the deck itself - and that's the point of your greatest isolation............. what you have to do is "just do and don't worry about it" - but when you have a choice always opt for maximum isolation. In the case of the floating slab - I can tell you that you will not succeed with fiberglass (or mineral wool) and the walls sitting on the slab - so forget that approach completely because it doesn't work at all.......... see how simple that is? Rod Nikodemos[/quote]

understood Rod :D to Rod, Eric (and everyone else interested of course) new question :shock: as i plan things the control room and tha practice room will be positioned next to each other "physicaly" separated by these huge concrete supporting beams walls shown in the first pic above. I'm planning to fill the space between the 2 beams with sand filled concrete blocks to create a contineous 25cm thick wall....now the question; building the inner cells of the rooms will create a 3 leaf system right? How would this 3 leaf perform(TL) compared to the normall 2 leaf system of my design? I mean compared to the "all drywall" 2 leafs between the rooms and not the outter concrete drywall 2 leaf.....would it be the same, worst or better due to the huge difference in mass and stifness of the concrete wall....i mean if it's worst well it is just something that i have to live with...but if it would be better then maybe i should concider building the same way around the whole practice room since this is going to be the loudest room and my main sound isolation concern... i've attached horizontal plans of the 2 and 3 leaf systems i'm talking about thanks Nikodemos

i guess this was out of topic :?

I'm planning to fill the space between the 2 beams with sand filled concrete blocks to create a contineous 25cm thick wall....

why?? cheers john

John Sayers wrote:

I'm planning to fill the space between the 2 beams with sand filled concrete blocks to create a contineous 25cm thick wall....

why?? cheers john

I have the same response......... why?? Rod

ooooops!!! seems like my plan is a major stupidity :oops: ....or i described it completely wrong(i hope so :D ) So let me try again...and please remember that i am a tottal crap in these things......show mercy :D :D if you see at my floor plan you'll notice that the control room and the practice(rehearsal) room are placed side to side separated in the original structure by a concrete wall. This concrete wall doesn't go all the way between the rooms....i mean its lenght is 3,50m and the lenght of the rooms is 6,20m. I thought it would be better to have the same wall structure all the way between these 2 rooms....I mean the concrete wall is there and it can't be moved, so a triple leaf wall is going to exist even at the half of the wall lenght...or this wouldn't be a 3 leaf :shock: ? So that's why i thought it would be better if the concrete wall was as long as the rooms.....i've attached a pic showing the part i was planning to build with concrete blocks......i hope that this is not stupid and nonsense because it seems quite logical to me :oops: I hope that i just made a terible explanation on my previous post :lol: Anyway i still wonder if the 3 leaf system i described on my previous post would "beat" the the 2 leaf one.....i mean in all the "3 leaf vs 2 leaf" topics and info i've found on the net there was a comparison between the same amounts of mass in the 2 walls....i mean i underestand that if, ypothetically speaking, i could split the mass of the concrete wall and distribute it on the outter leafs, this new 2 leaf system would easily overcome the 3 leaf, right?...... Thanks for all your help and comprehencion...... Nikodemos

Nikodemus, This is a difficult question. John and Rod indeed correctly responded without seeing your additional explanation where you ask: do I need to respect some acoustic symmetry in my construction to close that door opening and the surrounding walls. My calculation models aren't adjusted to compare this exactly. Still I try based on calculations and some additional guessing. Your drywall: 37.5 mm GB = 28.5 kg/m2 300 mm cavity with wool 40.5 mm GB + lead = 71.7 kg/m2 Your MSM here is around 25.8 Hz Your one heavy wall is with the GB 27.6 Hz Your one heavy wall is with the GB + lead 18 Hz This results as a tripple leaf around 29 Hz (rough guestimated, don't have my model here). But your mass of the wall is greater which compensates. I estimate the heavy wall combination around 11 - 14 dB better than the drywall. However you should lower your drywall MSM to ca 18 Hz if you should add the thickness of the wall to the cavity of the drywall (meaning your drywall runs flat over the opening of that door, keeping it completely in line with the surrounding area with a cavity then of ca 200 + 220 + 200 mm = ca 620 mm). I roughly estimate this will gain you 7 to 8 dB back. This is all plain theory, not taking whatever side effects into account. And I didn't made an in-depth study. (should need to make a model to do this). This is also based on the normal spectral energy content I use for studios (a lot of lows). At 25 to 35 Hz (less energy) you heavy wall will not be better, certainly not if you increase cavity of the plain drywall combination. You do not really need to add more wool in that cavity when you should increase that (no complete filling needed).

thank you very much.....i really apreciate it :D :D :D Nikodemos

well we just finished repairing the outter concrete cell (waterproofing, closing some windows etc) and the place looks quite better :D I decided to build the separating wall between the 2 rooms....i was thinking that since the TL on the very low frequencies would be pretty much the same getting the highest TL possible above 200 - 300Hz should be the goal. On the other hand i'll use the "double-drywall-with-huge-gavity" on the walls separating the practice room from the main recording room......and then when the studio is finished i'll test them both and let you know the "in place" test results :D :D :D ..... On the floating floor: I'm still trying to figure the cost/m2 for the Vibro pads to see if it would fit my budget.....I'm thinking to use the pads for the most critical(regarding TL) rooms and go for the mineral wool in the others :shock: Nikodemos

Nikodemos wrote:

On the floating floor: I'm still trying to figure the cost/m2 for the Vibro pads to see if it would fit my budget.....I'm thinking to use the pads for the most critical(regarding TL) rooms and go for the mineral wool in the others :shock:

Nikodemos, So then you think that just some of them you do with concrete? Rod

Rod, if i understood your question: I am planning to make them all concrete floating floors......i just though that i could probably use minerall wool as the concrete underlayment-spring in those rooms where is not going to be huge amounts of noise and go for a more profesional-calculated aproach for the more critical rooms using elastic pads under concrete.....so if you ask if i am going to use concrete as the floating floors ....yes i do. My main problem is that it is a big space (at least for my budget) 120m2 and i must fit it all in :( So if the "pads - concrete" sollution is within my budget limits i wiil go for it all the way...otherwise i will probably use the "mineral wool - concrete" apraoach on some rooms....i guess in that case my main concern is going to be the height of the floor to be the same in all the rooms to allow me to run wire - pipes through it. Do you think that something like this could be problematic? thanks Nikodemos

just some thoughts i would like to share with you.... I decided that floating a concrete floor is a really complicated work and it's no place for expensive experiments....on the other hand constructing a properly calculated 12cm concrete floor on elastomer pads for the whole 110-120m2 of my studio is out of my league(regarding cost) :cry: So i decided to make 12cm concrete floating floors based on properly placed and deflection calculated elastic pads which will allow a real room in a room aproach (inner walls on floating floors) in the practice room, drum booth and iso booth. These will be the rooms with the highest sound level. On the other hand in the live room i'm planning to record mainly acoustic instruments. So i was thinking to use an aproach by P.Newell for these rooms: a lightweight floating floor(multiple layers of plywood and drywall sandwiched) based on rebonded foam. Eric Desart also mentioned rebonded foam(well for heavy concrete floors :oops: ) and i was wondering if i could build a medioum weight floating floor on this kind of foam. I know that the MSM frequency is going to be high.....can things get better by using a thicker rebonded foam underlayment (8-10cm) and create a heavier (as posiible) floor? A last question: I read Rod's book regarding elevated and sand filled wooden decks.....could a combination be possible? I mean an elevated (mechanicaly decoupled) sand filled deck :shock: I'll post a drawning of what i mean thanks Nikodemos

Hi everybody i begun constructing a concrete floating floor using elastic pads from Vibro(a Greek antivabration product). The pads are 12,5x12,5x2,5cm and i'm using 2 layers(a total of 5cm height). According to the specs the floor will have a natural freq of 9 Hz under a load of 120kg per pad(double layer), so i'm going to pour 12cm of reinforced concrete (280-290kg/m2) using 2,5 pads/m2 with 5cm of 70kg/m3 rockwool in between. On the perimeter i'm putting pads every 60cm (according to the manufacturer) in order to support the extra load (120-170kg/m) of the walls. Then comes 2cm of plywood as a permanent base for the concrete pour. The floating floor is decoupled from the concrete walls by 5cm of 100kg/m3 rockwool. I'm following this approach for the Practice room, the Iso booth and the drum booth. For the Control room and the live room i'm going to build a floating floor on rockwool the way mr.Gervais suggested (walls floated separately). On the pics you can see the progress in the drum booth and the "finished" (no concrete yet) underlayment for the practice room and the Iso booth. please let me know what you think. Nikodemos