insulation confusion

[arjan]

hey guys,

i will be building a new studio soon.
but i have some questions about soundproofing...

the building is made of regular brick.
we'll put inner walls in it with double layer of drywall and insulation.
but what kind of insulation do i have to use?
the (cheap) fluffy stuff or the (expensive) rigid rockwool?

i already read rod gervais book about studio construction but since english is not my main languague and most of the used materials are not available in my country (belgium) i sometimes get a bit confused about what material to use.

help will be very appreciated.

arjan

[avare]

What IS your country? There is a reason for the user profile. Please use it.

[fifthflaw]

Originally Posted by avare

What IS your country? There is a reason for the user profile. Please use it.

to be fair he does state belgium in the post.

[avare]

You can use whatever is cheaper. You are not asking 703 yet, however from another thread here:

703 is the commonly used term in studio design for acoustic absorbent material. It is formally the registered trademark of Owens-Corning for OC’s 3 pound per cubic foot Fiberglas. There is nothing unique to 703. You can use any company’s product. At some places mineral wool is cheaper or available. With mineral wool, the 4 pound per cubic foot material is acoustically equivalent for our work.

In my part of world, 4” 703 is $3.80 per square foot . Roxul Safe n Sound (2.5 pounds per square foot and 3.5” thick) is 27 cents per square foot. A little off on the density thickness but ONE FIFTEENTH the price!

An interesting effect of the pricing is that gapping becomes a non issue. People at times consider having an air gap between the material to increase low frequency absorption. If a gap is used, there has to be some way to keep the material from falling into the gap. Typically this done with chicken fencing and strapping to which it is attached. The chicken fencing costs 50 cents per square foot here. 1"x1" strapping about 12 cents per foot. Putting a 3.5” gap behind the Safe N Sound would be almost twice as expensive as filling the entire space!

Andre

[emptyman]

if your building is made out of BRICK, why are you concerned at all about soundproofing? If there are other rooms in the building other than your studio, you'll need to soundproof between the studio and these rooms. If said room(s) are above or below you, the soundproofing techniques and materials are different than for side walls. More info. please...

[avare]

Originally Posted by emptyman

if your building is made out of BRICK, why are you concerned at all about soundproofing?

? A normal brick facade wall has an OITC around 40. IR 818 has detailed data. Fig 6 is a good start.

Andre

[emptyman]

Exactly.

My point is this: other than sound leakage through windows/vents/etc., building double drywall EXTERIOR walls is a waste of time and $. Exposed brick will sound infinitely better than drywall in a tracking room as well...

[avare]

Originally Posted by emptyman

Exactly.

My point is this: other than sound leakage through windows/vents/etc., building double drywall EXTERIOR walls is a waste of time and $. Exposed brick will sound infinitely better than drywall in a tracking room as well...

I still don't understand you. The OITC rating is for brick facade, drywall interior construction. Assuming the bricks 90mm thick, the STC of the bare wall is around 46. Do you consider that an acceptable value for sound isolation? That is ignoring value STC for music. What about heat insulation also?

Andre

[arjan]

hey all,

sorry for being not so clear in my first post...
here is a pic of the building where the studio will be built in.
as far for the brick walls i am not really concerned. we'll have brick/air gap/insulation/double drywall. i assume this will be enough for keeping the noise out and keeping the neighbours happy?
my biggest concern right now is the roof. as you can see on the pic it is made of some kind of "wavey panel". i dont know the name in english...
those kind of panels are thin... if it rains hard it sounds like a giant snare roll...
will the same kind of insulation (wavey panel/air gap/insulation/double drywall) be enough here? or what can i do to improve this?

as far as the kind of insulation to use between the brick and the drywall, is it correct to use the equivalent for oc703? something like 10cm thick rigid rockwool panels with a density of 50 kg per cubic metre?

thanks a lot,

arjan

[Anderson]

Originally Posted by arjan

but what kind of insulation do i have to use?
the (cheap) fluffy stuff or the (expensive) rigid rockwool?

We typically use two types when building in Belgium or this region of Europe, either:

- Rockwool 431 Adapt in 10 cm is the budget option and will give you good results @ ~ 7€ excl VAT/m². Any Isover/Rockwool distributor in .be will provide you with this one easy. It's a semi-rigid panel which can stand humidity well and has a density of about 45 kg/m³.

- Homatherm CL100 (so in 10cm as well) is the more expensive and efficient product (greener as well) @ ~ 13€/m² excl VAT and it has a density of 65 to 70 kg/m³. But you can only find it at a provider in Brussels called CARODEC, Chaussée de Wavre. This is a VERY good product.

Good uck with your project!

[Anderson]

Originally Posted by arjan

i assume this will be enough for keeping the noise out and keeping the neighbours happy?

From what you say (so take it with a grain of salt), I'd say almost for sure that it won't.

If you have neighbours, I'd be worried about mechanical transmission and less about aerial transmission of sound. The second can be managed rather efficiently with a proper Mass/Air/Mass system. The former, that's a tricky one that will require a thourough analysis and very precise implementation. From the pics I can see you are pbly at the top of a building (?), so therefore on a concrete slab which is 10 to 12cm thick with steel reinforcement that WILL conduct/transmit sound a lot. In this case, to prevent the sound from travelling to your neighbour (next to you and under you) will be costly and the system very heavy. I would suggest you check ASAP the load bearing capacity of the floor with a civil engineer if you are in this case.

If you're on the ground floor, and the floor is laying directly on earth (or on stabilized sand like they do in .be) it's the better situation and will require less treatment.

Maybe you could describe us your building a bit further and post more pics of the existing configuration?

[arjan]

hey anderson,

thanks for the help!
the good news is that the building is on the ground floor and is more or less standing free (not directly built against neighbouring houses)
on one side is the garden of an old lady who is almost deaf , two sides are built against workshops (a carpenter and a chicken farmer) and the other side is my garden.
we already made a layer of stabilised sand to even out the floor.
i think we'll add a layer of compressed pu foam and finish it with osb.
or do you know a better solution?
all inner walls and ceiling will be built standing free from the exterior construction.
do you think that 10cm of rockwool 431 and two layers of drywall will not be enough? what can i do to improve it?
and what do you think of the roof? it is made of "eterniet golfplaat" something often used here in belgium.

thanks a lot!

arjan

[emptyman]

okay - the further explanations and pic help a bunch! Other than your roof, it seems like you have an excellent "shell" to build your studio in. A rockwool product is definitely the way to go inside the brick because rockwool can handle some water and is excellent thermal and sound insulation. As for soundproofing, I'd rather go with a single layer of 5/8" drywall on 24" spaced steel studs with extra insulation behind - this way the drywall will actually flex and let some low frequencies pass through i.e. built in bass trapping!

[arjan]

what could i do with the roof to make it better?

[Eric Desart]

Originally Posted by arjan

what could i do with the roof to make it better?

Arjan,

That seems a rather large floor surface. What are the sizes of that room L x W x H? (details roof angling).
Are you going to do commercial work in that? If so it becomes subject to VLAREM II, with strict sound regulations.

As I see it, but you need to give more data and sizes, you better involve an architect to put some other roof on that building and strengthen that structure, which at a first glance is not calculated to carry anymore than it already does now.
It really has no sense to think about the walls or floor while your roof is still the limiting factor as well acoustically as well mechanically.

Once you decided on the roof (budget/type) then worry about the walls or floor.
That roof is a very weak spot. The fact that it's directed upwards only isolates with +/- 5 dB extra on top of the current poor isolation at a horizontal 90° angle. Taking the possible larger roof surface into account versus wall(s) directed to that neighbor that 5 dB will become less.
And calculating the sound radiation towards neighbors is NOT simply: "I play at 90 dB so 40 to 45 dB dB isolation should be enough". You must calculate here with sound power, not pressure. Then the radiating area surface comes into play. The inverse square law is not valid anymore for large surfaces versus relative short distances.

For the interested people some related documents I made showing some principles:

• Mass-Spring-Resonance calculation (Excel Sheet)
  http://forum.studiotips.com/files/MSMresonance03.zip
  
  
• An extensive MS Word document with lots of pictures explaining noise decay of 3D noise sources (as such building)
  http://forum.studiotips.com/files/No...omRadius_L.zip

You first must decide/know:

1. How loud do you intent to play and which kind of music (relative low frequent content)?
2. Which are the main sound paths and their individual (or grouped) contribution?
3. What are the levels allowed at the reception points?
4. Hence which isolation do you need?
5. How is the exact situation versus your neighbors (plans)?
6. Do you expect commercial activities (hence Vlarem II), otherwise you're still bounded to other laws/regulations/practices in function of electronic music?
7. Do you intent to use it during day, evening, night, Sundays and so on, or is everything limited to normal working hours?

Where do you live in Belgium? Belgium knows 3 different sets of laws/regulations for the 3 autonomic language regions. How is the area acoustically defined there? rural, whatever?
Note that music disturbance can be interpreter stricter (penalty factors) than other sound due to dynamic character.

With the information you provided now you can't start responsibly on that project, and nobody here can give you a complete or justified answer.
Flanking can become important. To define isolation one must detailed know and understand the complete circumstances.

You ask: how to improve that roof?
How much? To where? That's like trying to solve a formula without having the variables to enter.

I think you better search locally for some help to guide all these stuff, otherwise you become dependent of the goodwill of the neighbors. And that deaf woman certainly has family too. If you don't confirm with regulations they can close you down. In Belgium we don't count on deaf neighbors. They too have family and friends, and can move or die.

A guy who can possibly help you is Anderson here.

The Vlarem II (Environmental law of the Flanders) stuff is when you live in the the Flanders and do commercial activities (don't think that privately you are free from regulations), otherwise it becomes other stuff.

[arjan]

hi all,

been away for a while...

i think of putting a new roof on the building.
will "sandwichpanels" do the job?
that's a panel made of two metal layers with PUR foam between it, available in 30 to 80 mm thickness, or one layer of metal (outside) and a thin layer of aluminiumfolie (inside)
the last option is the cheapest!!
the construction is strong enough to carry that weight.

thanks

arjan

[Eric Desart]

Originally Posted by arjan

hi all,

been away for a while...

i think of putting a new roof on the building.
will "sandwichpanels" do the job?
that's a panel made of two metal layers with PUR foam between it, available in 30 to 80 mm thickness, or one layer of metal (outside) and a thin layer of aluminiumfolie (inside)
the last option is the cheapest!!
the construction is strong enough to carry that weight.

Arjan,

No, maybe yes.

I wrote a rather extensive answer. If one does not know exact targets, one can not say which solution does do the job.

In theory such panels have poor acoustic isolation.

Acoustics: flexible and heavy
Thermal and mechanical: stiff and lightweight.

[arjan]

eric,

the dimensions of the building are
W 8,5 meters
L 10 meters
H 2,5 at the low side, 4,5 at the high side.

the roof is angled towards a garden (neighbour)

i do plan commercial activities in there but it is a house i rent, so i'm only planning to stay some 10 years in that location.
i also do plan LOUD music in there, my main goal is recording bands from jazz to extreme death metal ;) so heavy drums, thundering amps... you get the picture...

the building is situated in a living area (? woonzone) in west-flandres so according to the vlarem norm ishould stay below 45db in the daytime and 35 db at night.

can i PM you? or even call you?
this would be a lot easier for me if i could discuss this in dutch...

thanks a lot

arjan

[Eric Desart]

Originally Posted by arjan

can i PM you? or even call you?
this would be a lot easier for me if i could discuss this in dutch...

Arjan,

I keep net and private separated.
I'm sorry, due to private circumstances I can't take on such job. And this one goes further (a lot) than a phone call.
I know Anderson here does do pro work (Brussels I assume).
Otherwise search the yellow pages for acoustic study offices.
If I should do it it shouldn't be cheaper.

Be aware that what you describe asks for serious investments. If it's rented and you plan to stay temporary that these investments are lost.

I once helped a guy out with his garage in comparable circumstances.
Here you can find his building thread:
Acoustics :: View topic - Paul's STUDIO BUILD DIARY

Take into account that your roof, due to its larger surface, when having similar isolation as the walls will radiate about as much sound to that neighbor than the walls themselves.
Which means, a heavy roof is needed and adjustments on the mechanical structure.
You can make something up with using large cavities between roof and your rooms, which at its turn could be used for ventilation and so on, but still ....

It's also possible that penalty will be applied on your 35 dB(A) to cover for impulse sound (meaning 30 dB(A)) and limits are set in function of the governing ambient background noise at night there.

This does not sound as a forum job to me.

[arjan]

if i understand correctely, installing a sandwichpanel-roof will not improve things a lot. so do you think it will be a waste of money (5000 euro)?
would it be better if i try to make the existing panels heavier by putting asphalt-roofing on top of it? it certenly would be cheaper!
are there other options?

[arjan]

oh, i forgot...
the company who make these panels (joriside.com) also makes panels with rockwool inside. they are of course more expensive...
could that be a solution?

[Eric Desart]

Originally Posted by arjan

oh, i forgot...
the company who make these panels (joriside.com) also makes panels with rockwool inside. they are of course more expensive...
could that be a solution?

Possibly,

They are better from a sound transmission loss point of view than the hard thermal foam versions. I know this stuff professionally very well.
But it remains "could".

You need very high insulation.
At 30 dB at your neighbors (35 - 5 for music) and you > 90 to 95, and with your description even more you need a lot of TL.

As an audio guy you're used to think in pressure. In function of isolation of a building you need to think in power, not sound pressure.
This calls for calculating that stuff.

Just to give you an idea of that roof.
Assume TL = 60 dB (inner + outer shell) which is a lot already for this type of low frequent sound.
Your roof is +/- 85 m2.

Very superficial: Lp 95 - 60 dB = Lp 35 dB + 10*log(S) where S is 85 m2 = 35 + 19 = Lw 54 db - 3 to 4 dB angle influence - guestimated 2 to 3 dB in-out (limited diffuse field correction in-out) = Lw 48/49 dB power from that roof alone which decays (Lp) in function of distance but FAR FROM the decay calculated by the inverse square law (which isn't valid anymore since the inverse square law relates to point sources, which a building next too a neighbor clearly is not).
Thereby you need to add all other sources as walls, ventilation and so on.
For this roof I don't count on these panels alone (that's plain impossible they can give enough, but the combination of the whole structure with inner shells.

Look in this doc to understand about sound decay in function of distance:
NoiseDecay-RoomRadius-A4.pdf
Free File Hosting - USAupload.net
It's possible that this doc will disappear after a certain time of inactivity. I couldn't find rules related to it.

I once made an animation to explain/show the idea of noise decay of large sound/noise sources.
Untitled Document
Details are explained in the above (copyrighted) pdf doc.

Since you seem to continue the superficial way with questions as "will this do it?" and "can this be the or a solution?" I will not answer this anymore.
I take your situation as it feels more serious than you do yourself.

In function of TL and environmental noise, certainly when you become subject to Vlarem II (environmental laws) we don't speak in terms of good, better, best anymore but in numbers.
And it's not as if you have enough spare here not to worry too much.
.