Questions regarding wall and Window + door assembly

Hello everybody. First let me begin with that I've read a lot in Rod Gervais book and on http://www.nrc-cnrc.gc.ca about the subjects, which have given me a lot of information and answers to questions, but some questions is still unanswered and some things I wish to discuss with you before I actually proceed with the build process. Simple history about the build: I have separated two rooms with a double leaf wall design, isolated from each other mechanically. One layer is approx 6 inch brickwall and the other leaf is 3 layer thick drywall on wood studs, where the studs is mechanically isolated from the rest of the building. Between the 4" studs I have 5" insulation(soft glassfibre) slightly compressed towards the drywall. Air gap between layers = approx 1' and 1". Now, I'm going to install double glass window and double door design in this wall, and I wonder what kind of doors and glass construction I need to meet the same TL values as the wall design. The windows is approx 3 sqfeet each and doors approx 6 sqfeet, wall approx 12' wide and 10' high So the questions simply are: - What is the TL value of the wall design? - What windows and window thickness will I need to meet the same value? - What kind of doors will I need to meet the same value? I'm thinking about maybe constructing them myself, or buy second hand ones, what do you recommend? I'm rather handy as I've built everything myself, and so far so good! I know, I know, it is equally as important with the right seals and so forth, and I know that part, so i'm strictly asking what you think will be good matherial and thicknesess for the window and door design. Thank you very much in advance!

Are you talking about just one single wall of a room, or about an entire "room-within-a-room" design? Isolating just one wall in a room won't be very effective unless you isolate the other four walls and the ceiling in the same way. - Stuart -

Soundman2020 wrote:

Are you talking about just one single wall of a room, or about an entire "room-within-a-room" design? Isolating just one wall in a room won't be very effective unless you isolate the other four walls and the ceiling in the same way. - Stuart -

Correct, this wall is single wall separating rooms from each other, a little experiment, I'm aware of the ineffectiveness of this kind of design but the circumstances around the rest of the room made me choose this way - to see if the isolation is enought or otherwise increase construction for further isolation.

I guess I don't understand what you are trying to achieve, or how you have accomplished what you say you have done with that single wall. How much isolation do you need? How loud are you on one side of that wall, and how quite do you need to be on the other? How did you manage to build just a single that you say is full decoupled form the rest of the building, yet manages to stand up by itself without falling over? And how can a single wall do anything to isolate the sound in one room from another room? Sorry, but I just don't see the point of building only 17% of an isolation plan, and expecting that it will work. Sound will simply find its way through the other 83% of the room that you didn't isolate. Unless you do the rest of the room too, then it hardly seems worthwhile putting in double glass and double doors. Any old piece of glass and door will do right now, I reckon. You would only need proper double laminate glass and double solid-core doors if you actually had a full MSM system. Perhaps you could post some pictures, diagrams, and a SketchUp model of what you have done so far. In any event, to answer your question: Figure out the mass density of the wall that you already have (kg/m2), then choose glass that is roughly the same mass density as that, or maybe a bit more. The same for the door. The idea is to keep about the same mass density across each side of the wall. So for example if yo figured out that your drywall leaf is 25 kg/m2, then you'd look for a type and thickness of glass that works out to roughly 25 kg/m2 as well. The seals are just as important as the doors and windows themselves. Without good seals, the rest is moot. st But once again, it doesn't make much sense to worry about such sophisticated and expensive doors and windows in a single ad-alone wall, unless the other walls, the floor and the ceiling are equally well isolated. Sound will simply flank around that wall on all sides, regardless. - Stuart -

Soundman2020 wrote:

I guess I don't understand what you are trying to achieve, or how you have accomplished what you say you have done with that single wall. How much isolation do you need? How loud are you on one side of that wall, and how quite do you need to be on the other? How did you manage to build just a single that you say is full decoupled form the rest of the building, yet manages to stand up by itself without falling over? And how can a single wall do anything to isolate the sound in one room from another room? Sorry, but I just don't see the point of building only 17% of an isolation plan, and expecting that it will work. Sound will simply find its way through the other 83% of the room that you didn't isolate. Unless you do the rest of the room too, then it hardly seems worthwhile putting in double glass and double doors. Any old piece of glass and door will do right now, I reckon. You would only need proper double laminate glass and double solid-core doors if you actually had a full MSM system. Perhaps you could post some pictures, diagrams, and a SketchUp model of what you have done so far. In any event, to answer your question: Figure out the mass density of the wall that you already have (kg/m2), then choose glass that is roughly the same mass density as that, or maybe a bit more. The same for the door. The idea is to keep about the same mass density across each side of the wall. So for example if yo figured out that your drywall leaf is 25 kg/m2, then you'd look for a type and thickness of glass that works out to roughly 25 kg/m2 as well. The seals are just as important as the doors and windows themselves. Without good seals, the rest is moot. st But once again, it doesn't make much sense to worry about such sophisticated and expensive doors and windows in a single ad-alone wall, unless the other walls, the floor and the ceiling are equally well isolated. Sound will simply flank around that wall on all sides, regardless. - Stuart -

on one of the sides the loudest sources will be guitar amps and drums, on the other side will be control room which need to be comfortably quiet to work long passes without getting tierd of high volumes. The circumstances are, above the ceiling there is approx 1' and 5" thick layer of small sawdust everywhere, which is damping the sound comming from the ceiling a lot. The walls connecting the rooms I have tested for transmission and I think they don't transmit too much sound which might make the isolation of the whole construction enought for me, but we'll see about it when the wall is up. Anyway if I build this wall correctly I can eliminate it as an issue of transmission, being able to focus on the different parts for more isolation if it's needed. The wall is isolated by acoustic hangers of this design, and the frame is standing on a strip of disconnecting rubber, making the wall totally uncoupled. Thank you for your answer. I will investigate the weight per square meter!

the loudest sources will be guitar amps and drums, on the other side will be control room which need to be comfortably quiet to work long passes without getting tierd of high volumes.

You plan to play drums and electric guitar in there? That's probably the two loudest possible sources of sound, and the drum kit is arguably the most difficult instrument of all to isolate. A drum kit can easily put out 115 dB SPL, and you need something under 50 on the other side, for a usable control room. I can't see a single wall doing much to accomplish that! (unless all the other walls, floor and ceiling are already spectacular isolators, even better than the wall you are planning) You seem to be missing the point that, despite your construction method, your wall does not prevent flanking. It is attached to the side walls on each end, the floor below, and the ceiling above. Sound will be transmitted from your wall into those other four, and from there through the building structure to the other room, especially the low frequency sound from the drums. ( And that's without even considering impact noise form the drum kit getting into the floor... ) Think of it like this: Imagine that sound is water, and that your room is an aquarium. In order to keep the sound in, you need glass all around the aquarium, on all of the sides and underneath. What you are proposing, is to build an aquarium that has glass on only one side... How well do you think an aquarium with only one side can keep water in? :) Unless your other three walls, and the floor, and the ceiling, are all at least as good as your single wall, then sound WILL get around to the other room, one way or another. It doesn't matter how good that single wall is,it simply will not make much difference. You could make it out of six inch steel plate and it wouldn't make any difference. It isn't a matter of trying things out and seeing if they work or not: it is a matter of the laws of physics. You can't get around the laws of physics by wishing they might go away: they won't. Unless ALL of the walls in your room are built the same way, as a proper MSM system, fully decoupled, isolated and correctly damped, then you are wasting your time and money. If you want to totally isolate a drum kit such that you can record well in the room next door, then you need the acoustic equivalent of two "aquariums" next to each other. In other words, two totally isolated rooms. A single wall cannot isolate a drum kit, any more than an aquarium with only one side can keep water in. It's a matter of physics. Once you build that wall and find out that it doesn't work, that the laws of physics apply to you just like they apply to everyone else, then you will have to demolish it again and build the entire room correctly. To me, that doesn't seem like efficient use of time, money and materials, but that's just me. On the other hand, if you have plenty of time, money and materials, and you like building things so you can knock them down again later, then there's nothing wrong with that! - Stuart -