What Glass To Equal Soundproofing of 150mm thick Concrete ??

Hey there, im hoping steve or anyone that would be able to calculate what glass i need to compete with 150mm of concrete poured walls, if i cant get close to equaling the 150mm of concrete STC and TL i will have to reconsider what to do!! I have no idea of accurate specs but this is the plan or idea.. HELP! haha Plan is 12mm thick laminated glass 12 inch air gap and 10mm laminated glass! does this sound like it will do the job enough from people hearing my drums bang away? through the walls.. its already pretty good! but i want windows as i have an awesome VIEW! any help would be appreciated! Govinda

As a rule, glass needs to be (ideally) laminated (helps dampen resonance) and be roughly 1/3 the thickness of the drywall* it's trying to match. (*Drywall = gypsum wallboard.) In your case (concrete), it might be possible to get away with 1/4 the thickness because concrete is more dense than drywall. Since your concrete is 150mm, you're looking at 40mm to 50mm. It seems like you're describing a single leaf system. You'll make major improvements by building another leaf parallel to that one. Finally, STC is complete MEANINGLESS CRAP when it comes to isolating drums. --Keith :mrgreen:

Hi keith. Here a mistake (slight reasoning error). Glass weighs ca 2500 kg/m3. Poored concrete depending on type/mix between 2000 and 2200 kg/m3 With drywall the mass of the drywall is only ca 1/3 of glass (also depending on type). That's where this rule of thumb originates from. The idea is to use as much mass of glass as drywall on each side, with a bit more for the glass to compensate for the lack of cavity absorption (which can partly be compensated by edge absorption). And using the max space gives some additional compensating gain also since the glass thickness difference with the drywall leafs can be used to add to the cavity. This means that to get to the concrete your window pane should become thicker then the drywall ratio, not thinner. But Govinda is indeed mixing a single leaf with a double leaf system here with different TL behavior. In theory one should aim to 2 panes with a cavity were the resonance of the double pane should about equal the TL of the wall at the same point. But no time to calculate this now. The window the OP described is a good one, but I should increase cavity some more and take care that the frame supporting at least one of these panes outside the wall has ca equal TL than that pane itself. And use edge absorption. But that banging away of these drums, and pretty good now for the wall is subjective. these neighbors will still hear this.

WOW Thanks for the quick responce sharward and eric!! As for the single leaf system, yes im aware of this being the major problem, in fact what i will eventually do is on the outside of the room, make an 8 inch thick concrete block core filled wall 300mm (12 inch) away from the 150mm (6 inch) wall did i mention that my ceiling is 8 inches thick of concrete! haha! it is slightly crazy what im doing but never the less fun! This is my 4th studio build... so now im confused as to what to do with the glass! for instance did i mention that the drum room is an old concrete water tank? a rather large one, its also a meter in the ground 3 meters high internally, i got a post here somewhere about it all, will update soon! So windows haha.. eric i know about all the work you did at galaxy and there was some serious glass there!! do i need to go all out? i know having 2 panes is more economical and i know a 12 inch airgap improves tl in most situations but i dont know what my tl would be now ?? and i dont have any measuring equipment!! ... hmm back to the drawing board i did learn one thing though that concrete and glass are fairly close in density! and sharward how is that drum room coming along? thanks guys, 8) G

Ok eric.. i keep reading your post and now its all starting to make sense! so what if i do wanna make it so the neighbours didnt hear a single thing!! how would i go about it? any simple explaination/suggestions that can involve light so i dont become some crazy white bat cave dwelling musician maniac that wants to attack the sun>? hehe Govinda :D

Govinda wrote:

...... As for the single leaf system, yes im aware of this being the major problem, in fact what i will eventually do is on the outside of the room, make an 8 inch thick concrete block core filled wall 300mm (12 inch) away from the 150mm (6 inch) wall did i mention that my ceiling is 8 inches thick of concrete! haha! it is slightly crazy what im doing but never the less fun! ...... so now im confused as to what to do with the glass!

Govinda wrote:

..... so what if i do wanna make it so the neighbours didnt hear a single thing!! how would i go about it? any simple explaination/suggestions that can involve light so i dont become some crazy white bat cave dwelling musician maniac that wants to attack the sun>?

:mrgreen: You've a fun manner of describing things. For the window: since that should be adjusted to the final wall, not worrying about that window now, but first deciding if you go to double up that wall or not. And if so, how exactly build up, and in how far will flanking be limitting? :) I'm an acoustician, not a magician. I can't tell from here how much isolation you need to exactly where, and how the current situation is. Up to 50 - 60 dB for music sound with high low frequent content one can easily use some standard procedures and gamble a bit. Going higher becomes exponentially more difficult (and expensive). Just some practical experience. Some half year back I build a couple of large windows ( :wink: let them build) about as you described. 10 mm and 12 mm, both standard laminated with 2 times 0.38 mm pvb (sometimes expressed as 55.2, 66.2) Frame taking very good care of (wood, lead, green glue, gypsumboard), cavity 300 mm (ca 12 "), good edge absorption. It keeps busy town noise out, but if someone blows his horn, or accelerates his car right beneath these windows (installed on 1st floor = second floor for USers I think, for us 1st floor <> ground floor) you can still hear this sound. If this should need to isolate drums with these annoying ( :wink: for you lovely) beats, from a flanking neigbor it shouldn't be good enough. (but good is relative. We've standards defining what should be interpreted as good)

:wink: haha thanks eric! well the thing is music (for me at least) is fun and i get paid for having fun with people and making them relaxed thus more creative! I cant complain about my job! If i could keep everyone out of my studio it would be built by now haha! possibly the wrong way!! haha Right now im finishing the airlock to the tank, then im gonna do a proper test with my neighbours to see how much they love the drumset!! if they dont run over with shotguns the big thumbs are up!! if they throw rocks at me, maybe i need to add another layer with air inbetween? :lol: haha it seems like i should test it out before i do the windows? i know where they have to go so ive planed ahead, and we both know windows are gonna be a weak link even with me having one partition, the 150mm conrete water tank one!!! as for the flanking paths: the tank is 1 meter in the ground if i added an extra layer it would be outside as i dont wanna lose to much internal floorspace as i like to hear some movement of air in the room, so there will be a bit of flanking..an extra slab and footing would have to be poured all around the tank and i would form concrete for a new ceiling, the ceiling ontop of the extra walls would have to touch the tank... so i dont know how good this would end up.... i know its a cheap option.. but its really a guess, not a hell of alot of solid answers.. thats why im talking to you eric your some what the magicman acoustician, do you want me to give you lots more details?? I have all the details in the world!! but this could get very boring and you might wanna run out of your neandrethal batcave and scream at the sun also!? hehe my wife thinks im a caveman! maybe im the only one? its all about the luuurve! Govinda

hmm so 40-50mm glass will do the trick of matching my walls?? eric?? Anyone?? HELP! hehe

Depends on the matching wall (what material it's made of, what density) Matching a concrete wall of 150mm is difficult, since glass is about as heavy as concrete (density both are somewhere between 2000 and 2500 kg/m3) you'll have to place a 150mm thick glass pane.. ghehe, thaz some heavy shit. Prolly difficult to get too. To match a drywall wall (about 700-800 kg/m3) you'll need a pane about 1/3 of the thickness of the drywall. So a 3sheets 15mm drywall needs 1x15mm glass.. do the math and let the suit keep wearing you. (huh?)

Thanks Ro....Holy smoke.... sounds almost impossible! i can see cranes and all sortsof dramas!! The thing is i would really like to mix a single leaf wall (150mm concrete) with a window thats dual pane to get the same stype of TL and STC ratio.. it seems like its not a straight forward answer?? thoughts anyone>? Govinda

Well, as said, sometimes you've gotta work with what you got. When you keep with the single concrete wall, add just 2 panes of laminated class. Get the thickest pane(s) of glass you can find, atleast.

the thickest glass i can get here without making a custom order is 30 mm single pane non laminate! do you think a 25mm sheet an 8-12 inch air gap and a 30mm pane do it? Govinda

30mm single pane (floated?)... do they even make'm that thick? dang. If that's the only glass you can get your hands on, then yeah sure.

thats the one 30mm single pane floated!

hmmm Is there anyone who has that lovely program used to calculate glass walls and stcs etc that could pretty please make a quick calculation for me? WOW :P

I'm curious what the experts here think about this product as a solution. http://www.pittsburghcorning.com/builders/newproducts_thickset.asp The Vistabrik claims STC 53. Two advantages would be the ability to have a curved window and no cranes!

yeah i have used s similar product in my studio kitchen.. it used to leak tons of sound next door once those glass blocks were installed.. no more sound leak! sweeeeet

The VISTA is a SOLID piece of glass with a thickness of 3", so yeah that's pretty heavy. In that case I say YES great! but.. the weakpoint will be construction or better; the space BETWEEN the blocks. You'll prolly glue them together, make damn sure it's tight. Even then it's still your weakspot.

VISTABRIK * Ultimate glass block solution * Three solid inches of glass which resists bullets, fire, noise, graffiti and force able entry * Classified by UL® for use as a 45- or 60- minute-rated window assemblies * Two available patterns: clear for good visibility or stripped for added privacy * Thicker-face = 3.0" * Sound Transmission Class (S.T.C) = 53

And, again, STC don't mean shit in our line of business. But I figured you folks read this forum and I'm not telling you any news here.