Ease my ambivalence, please!

Hey! First and foremost, HUGE thanks to all the people who contribute to cramming this forum with such useful info!! I found it just a week ago and have now comfortably secluded myself from all the non-studiorelated diversions, such as social presence, food and sleep. :? :) Well, how to begin? Quite simply, I grew tired of paying over-sized rental fees every month for my old rehearsal studio in Malmoe-city so I decided I'm going to be my own landlord and build my own place, saving money doing so. The object I have at my disposal is my garage, which is attached to my house in a "one-piece" sort of fashion with a second garage in between. The house is situated way off in the countryside, but even so I do have one neighbour about 3 meters away (his house being 7 meters off). Being outside in his garden, he would probably be annoyed by the sound level that my band (pretty loud rock) would produce. Being indoors, he would probably be able to hear the most of it, f.x. if he was trying to sleep! 8) What I want to do is to make me one single isolated rehearsal room of my 30 m2-sized garage. I will be recording (in my own humble kind of way), so that's also a purpose for the room, and I'll be mixing some stuff as well but I'm really not after the perfect setting for doing that. If mixing works out o.k. once the room has been isolated and acousticly treated, that will only be a bonus. I'm far, far away from being a decent sound engineer anyway. So far, I'm just having fun with it, which is what it's all about! The existing walls consist of (from the inside and outwards): single gypsum board + wooden studs with glasswool + gypsum + airspace + brick wall. I don't know too much about the roof yet, but it's basically isolated with two leaves like the walls. The weak points right now are the old windows in the back and the very leaky garage-door that opens vertically. First question: 1) I'm thinking of replacing the windows with new ones, but nothing expensive. Just normal 3-glass windows. Will that be enough considering the isolation of the inner room described below? Also, the garage-door will just be replaced by another, thicker pair of doors that open horizontally. This is because I want to keep the profile of a garage... and also I don't want to go into the whole masonry-thing. Will a thicker garage-door suffice? (I will put glaswool covered with fabric behind one of the doors and fix that door in the ground. Rubber strips isolating around it.) Ok. Now, here's what I think about the isolation. I have thought a lot about what type of floor-construction would be adequate. At first, I only saw one alternative and that's floating a whole damn room within the existing one. Then I started reading the threads on this forum, where the "floating floor"-model was questioned and I got some new ideas. You see, my garage has a concrete floor, possibly connected to the other garage, but probably not to the main house since it's based on a crawling space and not a solid foundation. And what's more I don't have much height in my room, so I'd really love to ditch the whole "building up my floor 15 centimeters"-concept. Question no 2: 2) Since the concrete floor gets really cold in the winter here in the north, and I don't wanna have to spend a fortune every month keeping the room reasonably warm, is it possible to lay a 2,2 cm fibreboard with a protective sheet underneath and use it as a base for the walls (and ceiling) of the new room? (Laminated floor and carpets covering the new floor-area.) How would it affect (a) isolation? (b) acoustics? I feel psychotic to even ask this, but... Erm... :P :oops: :P :oops: :P Or - putting it in another way - what is the lowest profile that still sounds good acousticly? Rightee! On the (imaginary) fibreboard I would then place floor-sills of wood and build up 7x4,5 cm studs at 90 cm centres. Gypsum boards on both sides of the studs. Glasswool in between. Four walls making a new room inside the garage, sound-class door (-30dB), windows covered or possibly accessible via a "pull-out-hatch" in the new wall. 3rd question: 3) I don't have much of a clue about how effective my construction will be. This is why I want to put one or maybe two gypsum boards on the outer side in order to have the choice of adding more boards on the inner wall after the room is finished. So! Let's say I've got only one board on the outer side and two on the inner side. If I add one or two more, how will the ratio 1:3 and 1:4 gypsum boards affect (a) isolation? (b) resonance from the wall (and thus the acoustics)? I think I'll stop here for now. I hope someone has the heart to help a complete moron put his grand plans into action... :roll: I'm a total new-beginner at this... Be kind...? Cheerios!! /JOHAN the Swede 8)

Johan, welcome - but before I agree to "be kind", I need you to resize your drawings per this http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3231 (I think that just by cropping the unused white space you'll be close) Sorry, but I'm not the only "old fart" with failing eyesight that only uses 1024 wide monitor settings... Steve

Thank you! All fixed now! Must be somewhat of an old fart myself for not seeing that... :) So long for now! /J.

Posting some new pictures... ...including a drawing of the inner walls. Two different versions. In the first one, the wall itself is thicker, with staggered studs of different sizes to save some space but still get the benefits of a decoupled construction. Just an idea - wonder if it'll work? A layer of asphalt board has been sandwiched between the two gypsum boards in the inner leaf. It's supposed to act as a simplified spring. I'm considering using green glue instead.... In the second drawing, I'm a bit more optimistic about my isolating-needs. Single-stud construction with dry wall on both sides. These other pictures are just for getting a basic understanding of the environment as well as the design of the existing room. I'll be back soon...

The walls:

Hey Johan, Great having you aboard. While you stated "First and foremost, HUGE thanks to all the people who contribute to cramming this forum with such useful info!! I found it just a week ago and have now comfortably secluded myself from all the non-studiorelated diversions, such as social presence, food and sleep. Confused" I'm still under the impression you haven't grasp the whole M-A-M principle (?) So, better re-read them stickies. I know, there's SO MUCH INFO here you'd be occupied for atleast a month of two... I'm sure you'll notice a term called "2 leaf"..... ;) (and not only for walls...) Oh, Rod's book is also a good resource...

Hey, Ro! Thank you for replying! Hm... I think I might be misinterpreting the whole floating wall as one single "mass" and then the outer brick-wall as the other "mass", with airspace in between... If this is where I went wrong, then I'd better remove the dry wall on one side of the frame....? Add it to the other side? I bought the book! Gonna study hard! Sincerely, JOHAN

Johan, The 1st layer of gypsum after your outer wall is causing you to not have a M-A-M setup. Your outer wall is considered your mass, the 1st sheet of drywall after that is mass and the inner drywall is another mass. Seems like you need to omit the drywall after your outer wall. The way you have it set up it's M-A-M-A-M. Like Ro said, check out the stickies for great explainations on this. Also, if you research, there are LOADS of info on this topic on here.

Johan wrote:

Hm... I think I might be misinterpreting the whole floating wall as one single "mass" and then the outer brick-wall as the other "mass", with airspace in between... If this is where I've went wrong, then I'd better remove the dry wall on one side of the frame....? Add it to the other side?

Exactly, that might do the trick.

Great! Thanks! More drawings to come... /J.

Johan wrote:

A layer of asphalt board has been sandwiched between the two gypsum boards in the inner leaf. It's supposed to act as a simplified spring.

You have no idea whether or not such an experiment will make things better or worse. You're better off using methods and materials that have a proven track record of success. --Keith :mrgreen:

Hi! I actually read somewhere that asphalt boards can generate an effect similair to that of green glue...??? I don't recall exactly where I read it, though. It doesn't seem to be a very prevalent technique either.... I'm gonna trust you and leave the asphalt board out. :) Gratefully, /J.

Johan wrote:

I'm gonna trust you and leave the asphalt board out. :)

Don't put your trust in me -- for the most part, the burden of proving that a product works for a particular purpose is generally on the maker of the product in question. 8) Unless you have test results from an independent lab that proves an assembly is improved by the inclusion of a particular product, don't use it. --Keith :mrgreen:

stick with greenglue or the eqvivalentproducts; in Sweden it would be either Noisekiller from http://www.vibratec.se or DG A2 from http://www.swedac-acoustic.se/.. lycka till! a :arrow:

First decide if you want to rehearse at night or not with your metal hardcore punk rock band :D This fact will define your sound insulation requirements. In Portugal for residential areas the noise limits at night are 45 dB(A) and during day 55 dB(A), maybe it's slightly different in Sweden. 10 dB of extra sound insulation does not appear to be much but it is ! Let's say your band is playing at 100 dB(A), your current garage attenuates 20 dB(A), distance attenuates 15 db(A) and your neighbor's wall attenuates another 20 db(A), you will end up in your neighbor's house at 45 db(A). Oh, that's fine... after all you don't need any sound insulation at all ! :-) Unfortunately this is not that simple since the type of noise you are producing has quite a lot of low frequency energy, meaning this will be a bit little more difficult to solve. (There are also a bunch of rules concerning environmental acoustics that are too long to explain here but 45 dB in a SLM can be translated into an higher value depending in the characteristics of sound etc etc) Also your windows and door are weak spots of your garage and must be replaced or improved, particularly if they are faced towards your neighbor's house. That means those windows have to be turned into a double windows system of different thickness (NOT triple glass windows!), the garage door has to be changed. I would probably say to do a room-in-a-room project although it depends really on how loud you are really playing etc etc The way I see it you have two choices: 1) solve the weak points and do a room-in-a-room project 2) solve the weak points and build a second wall inside the room way from the wall that faces into your neighbor's house and also in the ceiling. You can built a structure that you normally see in music studios construction or use something like this to place the gypsumboard (http://www.cdm.be/documents/pdfs/cdm-iso-t.pdf) Also keep in mind you will probable need some kind of HVAC solution to your problem... PS : if you want to float the floor there are several brands that sell materials for that purpose CDM, DANOSA, TEXSA, AURALEX etc PS 2 - it would be nice for you to get a cheap SLM (sound level meter), play your CDs loudly in your garage and check for the difference near your neighbor's wall. The cheap SLM won't show you real values (you need a calibrated SLM for that) but will give you an idea what is the real attenuation Andre

First decide if you want to rehearse at night or not with your metal hardcore punk rock band :D This fact will define your sound insulation requirements. In Portugal for residential areas the noise limits at night are 45 dB(A) and during day 55 dB(A), maybe it's slightly different in Sweden. 10 dB of extra sound insulation does not appear to be much but it is ! Let's say your band is playing at 100 dB(A), your current garage attenuates 20 dB(A), distance attenuates 15 db(A) and your neighbor's wall attenuates another 20 db(A), you will end up in your neighbor's house at 45 db(A). Oh, that's fine... after all you don't need any sound insulation at all ! :-) Unfortunately this is not that simple since the type of noise you are producing has quite a lot of low frequency energy, meaning this will be a bit little more difficult to solve. (There are also a bunch of rules concerning environmental acoustics that are too long to explain here but 45 dB in a SLM can be translated into an higher value depending in the characteristics of sound etc etc) Also your windows and door are weak spots of your garage and must be replaced or improved, particularly if they are faced towards your neighbor's house. That means those windows have to be turned into a double windows system of different thickness (NOT triple glass windows!), the garage door has to be changed. I would probably say to do a room-in-a-room project although it depends really on how loud you are really playing etc etc The way I see it you have two choices: 1) solve the weak points and do a room-in-a-room project 2) solve the weak points and build a second wall inside the room way from the wall that faces into your neighbor's house and also in the ceiling. You can built a structure that you normally see in music studios construction or use something like this to place the gypsumboard (http://www.cdm.be/documents/pdfs/cdm-iso-t.pdf) Also keep in mind you will probable need some kind of HVAC solution to your problem... PS : if you want to float the floor there are several brands that sell materials for that purpose CDM, DANOSA, TEXSA, AURALEX etc PS 2 - it would be nice for you to get a cheap SLM (sound level meter), play your CDs loudly in your garage and check for the difference near your neighbor's wall. The cheap SLM won't show you real values (you need a calibrated SLM for that) but will give you an idea what is the real attenuation Andre

Hey! Been keeping a lower profile for a few weeks now, reading Rods book and the most current threads on the forum. I think it's time to post some of my thoughts at the moment.

stick with greenglue or the eqvivalentproducts; in Sweden it would be either Noisekiller from http://www.vibratec.se or DG A2 from http://www.swedac-acoustic.se/..

Thanks, A! Do you know how these two products compare to Green Glue? Are they equally effective? You used Noisekiller, huh? What are your thoughts on it?

First decide if you want to rehearse at night or not with your metal hardcore punk rock band This fact will define your sound insulation requirements.

Hey, Andre! This I did actually consider! Even if I might come across as a little impatient... :lol: What I'm envisioning is being able to rehearse with a full rock band (probably around 100 dB) without my neighbours hearing it inside their house. Also, it would be ideal if they weren't too annoyed when being outside in the garden. There's a freeway only 200 meters away from our area, so some of the music would be drowned by the traffic noise. I guess I'd be happy if the music was at 30-40 dB, measured in their garden.

...your windows and door are weak spots of your garage and must be replaced or improved, particularly if they are faced towards your neighbor's house. That means those windows have to be turned into a double windows system of different thickness (NOT triple glass windows!), the garage door has to be changed.

After reading Rods book, I realized that I'm gonna need laminated windows with a well-isolated construction. Even so, it will probably still be a weak link. As for the garage door, I'm considering building a new outer wall with a smaller 30 dB-door.

Also keep in mind you will probable need some kind of HVAC solution to your problem...

I'm painfully aware.... I'm gonna check for prices with some of the local ventilation companies. I fear that my wallet will jump out of my pocket and smack me in the face....

...it would be nice for you to get a cheap SLM (sound level meter), play your CDs loudly in your garage and check for the difference near your neighbor's wall.

I'll do that! :) Ok. There are still some loose threads, obviously, but I don't see any other alternative than to go ahead with this project. So, while I'm still brooding on the HVAC-solution, electricity... I do know that I have to beef up the existing walls. The construction I will do is (from the inside and out): 12 mm drywall (=½") sandwiched damping system 12 mm drywall 100 mm studs on separate floor sill + glass wool (supported with wire) 30-40 mm airspace 100 mm studs with glass wool and 3 x 12 mm drywall between studs. 12 mm drywall 60 mm Brick wall I've removed all the old drywall and glass wool facing the inside, revealing the studs and the outer layer of gypsum. I'm gonna try to use as much of the old gypsum boards as possible when inserting new layers between the studs. Q 1: I can't find a clear enough explanation of how to fix the drywall sheets between the studs. Could someone point me towards a thread where this is thouroughly spelled out? I know there has to be one! :oops: Q 2: The brick wall is obviously vented with an airspace behind it and a couple of holes in the mortar to circulate the air. Would the airspace behind it make it a third leaf, even though it's not airtight? The ceiling will be (from the inside and out): 12 mm drywall sandwiched damping system 12 mm drywall RC-2 channel 200 mm joists with insulation and 3 x 12 mm drywall in between wood panel asphalt sheet roof tile Next time I'll post some new pics and drawings. Take care y'all!

...about the "how to fix the drywall sheets between the studs"-question: I found a good resource on this in Sharwards thread. If I understood it all correctly, I should glue an OSB-sheet to the outer drywall, attach cleats to the studs to hold it in, caulk and then go on beefing up the wall with gypsumboards, screwed into the OSB. /J.