New Home Rehearsal/Recording Studio build. advice?

Hello :D I was recently directed to this forum by a friend of a friend, mod Gregwor after looking for advice on the studio/jam-space I'm building in my new house. the goal A large multi purpose room, primarily for Metal band rehearsal, also for recording, and mixing. I figure I'll put a desk behind my drum set and just swivel my drum stool around to work on my computer. I'm the guy that has to hit "record" and then hit the things with sticks anyway. keep my neighbors happy, and let my family sleep while the band playing. The space I purchased this house last July, the big selling feature was that there is a 24'x20' addition on the back of the garage. Perfect for the band. I visited each of my neighbors to let them know I had a loud band that would be practicing here, and that I would look into soundproofing as best I could in the coming months. I've never had any complaints, but talking to some of my neighbors since we've started practicing, if they're outside, they can hear us clearly, though inside it's tolerable. For my own family in my house, they can hold a conversation when we're practicing, but it would still be good to bring it down to where they can go to sleep at night if I'm still up playing drums. Here's an overview of the property and the layout of the house, the small red square is the space I'm working with, the large red square is the property line: and just a rough idea of the house layout: Since I'm planning on building a room within a room, and the ceiling was already only 8' high, building a floating room would leave very little head room, so I had the roof trusses re-done to vault the ceiling. now it's 8' at the walls and 13' at the peak. whew, that was expensive. The interior measurements are 23' 2" by 19' 6" so it appears to be 2x6 construction on the north and south walls, and 2x4 construction on the east and west walls. All sitting on a concrete slab. Here are some photos during the truss replacement, and then a photo from each corner of the room as it currently sits, and one more exterior shot: So that's what I'm working with. Unfortunately I do not have any sound level measurements, as I'm now at the stage where I need to build the darn thing before I put all the band equipment back in there, and didn't have a measurement tool or the knowledge that I needed to measure beforehand. With the coronavirus situation going on, the band isn't getting together for a while, and in order to be productive during this time, I want to get this construction project done. the original plan: My original plan before speaking to Greg was to build a floating room in here, with no parallel surfaces, and a floating floor. 2x4 frame walls, studs on 24" centres, caulk every joint with green glue, 1/2" OSB on the outside and 1/2" plywood on the inside with rockwool insulation. The overhead garage doors are to be replaced with the widest sliding glass doors I can get and I'll put a window on the inner walls everywhere there's one on the outer walls, as it would be a shame to just block all that natural light. When I was thinking there would be a floating floor, I thought it would be great to have flush mounted power outlets in the floor, mostly for the guitar players' pedalboards, but I can scrap that idea. I had been working on sketches and sketchup models (using sketchup web as I thought that was the only free version still available, anything further will now be done in sketchup make). what I've learned so far - Floating the floor is pointless (or at least too expensive and difficult to get right) - Skewing the walls is pointless - I need to worry about HVAC the new plan: Straight walls with treatment, straight onto the concrete slab. still doubling the 4 walls and the ceiling. Much simpler framing for me. Vent into the garage, where the high ceilings will let me attach some big silencer boxes up high on the wall. here's a couple photos of the garage, this is up against the eastern wall of the jam-space (the wall with the dark brown garage door) still need to do my hand sketches and sketchup designs for this new plan Budget I'm certainly ignorant as to how much all this is really going to cost, but hoping to keep it to $10,000 Canadian dollars (maybe 15). My Questions: - should I use self levelling epoxy on the concrete slab first to level it out. it's pretty old and certainly not perfectly level. - leaf design. inner wall, outer leaf, just one sheet of OSB ok to keep mice out of the insulation. inner leaf, 2 layers of sound isolating drywall with green glue in between? - what else am I missing or doing wrong? Thank you to everyone who read this far. :shot:

Great to have you here dude!

- should I use self levelling epoxy on the concrete slab first to level it out. it's pretty old and certainly not perfectly level.

 That would help make framing easier for sure. What would you want to use for flooring material?

- leaf design. inner wall, outer leaf, just one sheet of OSB ok to keep mice out of the insulation. inner leaf, 2 layers of sound isolating drywall with green glue in between?

 I'm sure you checked out the MSM calculator I linked you to. You're requiring high levels of isolation. Therefore, you're probably going to have to beef up your outer leaf to get the surface density up to where it needs to be. That means tearing off the green drywall and adding more material (OSB, plywood, or drywall) to the existing ceiling. You're going to have to make sure the existing ceiling is really heavy because you're going to have to fight with a 3 leaf ceiling. For your inner leaf, I recommend using some thick (like 3/4") OSB for your first layer, then 5/8 fire code drywall. Both inner and outer leaves need to be air tight. To keep costs down (but build difficulty higher), I suggest building as much of this inside out as you can. Specifically the ceiling. Ultimately it does save you space and material.

- what else am I missing or doing wrong?

 You mentioned you wanted to keep your windows. The thick laminated glass you require in order to maintain your sheathing surface density, and ultimately your isolation, is super expensive. After you price out what you need, you might realize that a huge chunk of your budget will go to just glass! If you can afford it, cool. Otherwise, I'd suggest keeping only one window. Also, for the sliding glass doors, the same issue exists with those. But in order to have great isolation with sliding doors, you basically need to use specially built sliding doors as ones at places like Home Depot simply won't work well enough. Other things you didn't mention or didn't detail enough were: - HVAC supply and return should be opposite one another in your room so that the air flows from one end of the room to the other. - Are you doing forced air or ductless mini split to condition your air? Mini splits are great in that the footprint of the unit as well as the ventilation for them is way smaller than forced air. - Either HVAC route you go, you need a drain for them. - Doors (slab, hinges, seals, automatic door closers, handles (can't be through the slab) - Electrical can only have 1 penetration into your sheathing, then the rest has to be surface mounted. This is also where inside out construction excels as you can hide all wiring and make any outlets or switches look flush! - Talk to structural engineer to figure out how you need to support the super heavy inner leaf vaulted ceiling --> engineered wood (LVL)??? - Research how to ensure your vapour barrier needs to be installed (should be in your inner/outer leaf cavity up against your inner leaf sheathing) Lastly, to help with the volume issue, you should talk to your band about using in ears. If you use amp emulators or just load boxes with cab simulators for their real amps, the only thing making volume would be your drums. And putting your drums on a drum riser such as this one:  It won't help with blocking the sound any more but it could help slightly with structure borne transmission through the slab. Lastly, when you post your SketchUp files, be sure to go into model info and purge unused. This should help keep the file size smaller. Also, save as and choose an older SketchUp version such as 2014 so that everyone can easily open the file. If it's too large for the forum still, just upload it to drop box or google drive... somewhere where it'll stay hopefully forever. That way, 10 years from now when people are studying on the forum they can still download it and learn! I look forward to helping you with and following your journey! Greg

Thanks jumping in :)

What would you want to use for flooring material?

we've been surviving on the raw concrete just fine. I'm thinking I'm going to run out of budget before I go into flooring material, and it might be something to come back to a year or two down the road. I have a couple hunks of carpet I can lay down, but they wouldn't cover the whole floor.

That means tearing off the green drywall and adding more material (OSB, plywood, or drywall) to the existing ceiling.

again, budget constraints... I don't want to go demolishing any existing material if I can use it. I'm hoping to get away with mudding/caulking everywhere on the existing green drywall and OSB on the ceiling, seal it up, and then adding one more layer to it.

The thick laminated glass you require in order to maintain your sheathing surface density, and ultimately your isolation, is super expensive.

alright. better just block them up then.

Also, for the sliding glass doors, ...

yeah, found a guy at a window/door place in Kelowna who's a guitar player himself, so leaving it to him to get me some well isolated sliding glass doors, as well as the man-door on the side. HVAC, I guess I will be putting some of those silencer boxes on either end in the higher part of the room where the vaulted ceiling gives extra room, on the east and west sides. Haven't thought about air conditioning yet, but the heat didn't get too bad in there last summer. Adding AC might be another "no budget now, revisit later" thing. Electrical and framing, more "will talk to my guy" parts to keep working on. Vapour barrier: my contractor that replaced the roof trusses advised that I just need to make sure there's only one layer of vapour barrier, and the existing wall already has it, so that'll be the only vapour barrier layer.

you should talk to your band about using in ears.

we're already on in-ears, but the guitarists are just on their real amps. one has a cab-sim direct out box that goes in line between his head and cab, but it's not a load box, so he can't play silently. emulators or load boxes aren't going to work for them. guess that's about it for now. I suppose I'll start on taking out the existing windows and filling the spaces, and perhaps sealing up the existing layer of drywall and OSB if that's something I might be able to get away with.

Unfortunately your drawing indicates that you are going to have a 4 leaf system. Anything more than 2 leaves is basically a no-no. You are going to get poor isolation with more than 2 leafs in the low problematic frequencies. You'll be wasting a lot of material ($$$) and time doing that. If you're able to re-use some existing drywall, sweet. However, unless it's heavy old school fire code drywall, you're kind of wasting your effort. New home builds typically use what is called "ultralight" drywall. It's literally half the density and cheaper. It is easier for contractors to work with. Sadly, when it comes to isolation, mass is so important. Heavier the better. Using my calculator, you can see this for yourself (note, the calculator is based on a 2 leaf system because that is what you should be constructing!) viewtopic.php?f=1&t=21770 Therefore, I can't stress enough to just rip off the green drywall, build a single inner leaf that is inside out and that's it! Simple. The amount of drywall you might waste by throwing out that green drywall is minimal in the big picture. If it's actually heavy fire code drywall, you could use it to beef up your outer sheathing. This is because you will need ~14.5" strips of it to go between your existing studs (presumably 16" o/c). Greg

Ok, so I'm not ripping of the green drywall to replace it with anything, it's to remove a leaf so it's just exposed insulation, to make it 2 leaf construction? Don't understand how another layer of material would be a detriment, but you're the expert :P. So from outside-in the layers should go: siding -> house-wrap -> whatever sheeting is under there now -> wood frame/insulation -> poly -> air space -> wood frame/insulation -> sealed OSB -> green glue -> sealed heavy drywall. something like that? the poly layer is on the inside of the existing walls, can it stay there? what's the best way to hold the insulation in place on the exposed side? thanks,

The reason for ripping off that drywall is to increase the air gap between what will be your outer and inner leaves. Smaller air gaps have higher resonances = worse sound reduction. By increasing the air gap between two layers of decoupled mass you lower the cavity resonance = better sound reduction. In some cases by simply making your cavity just an inch deeper you can achieve the same sound reduction (transmission loss) as if you put an extra layer of mass on your leaves. Therefore it saves you time and money and costs nothing (other than space). Paul p.s. the poly in your proposed assembly I'm guessing is your vapour retarder? You might want to check it's in the right place... here in the UK it would go behind the inner leaf mass (warm side of the cavity insulation). The insulation in the cavity should be a full fill, it doesn't need to be held in place. In essence, the insulation IS the air gap.

yeah, the poly is the vapour barrier. without building a new wall it's on the inner side, but once I build a new wall, that would put the poly outside of my whole inner set of framing. So I suppose I need to remove the poly from where it is now, and reinstall it on the inside of my new framing that I'm going to build before I put the inner leaf on eh?. thanks,

Bretton M wrote:

yeah, the poly is the vapour barrier. without building a new wall it's on the inner side, but once I build a new wall, that would put the poly outside of my whole inner set of framing. So I suppose I need to remove the poly from where it is now, and reinstall it on the inside of my new framing that I'm going to build before I put the inner leaf on eh?. thanks,

You should check where it needs to go in your location, it varies depending on climate. If you have a climate like the UK (mostly rainy, cold and occasionally warm in the summer) then yes, most likely you would indeed need to remove it and put a new one up on the other side (behind your inner leaf mass, in front of the cavity insulation). You won't be able to re-use the existing poly as it'll more than likely be torn up when you remove it and have holes in it. Paul

The barrier will have to go just under your inner leaf sheathing. Also, I highly recommend building your walls and ceiling inside out. If not the walls, then for sure the ceiling. Lastly, regarding your out to in list of materials, you will have to “beef up” your outer leaf sheathing. You do this with strips of material such as drywall in between your studs. Your put green glue between the existing sheathing and your beer up material. Since green glue has no stick properties, you will screw what we call “cleats” onto the studs to hold the drywall in place. I recommend sealing the existing sheathing using dap dynaflex 230 in white. Basically just apply the caulk around each stud bay and sheathing seam. Make it air tight. Then after you put up your beef up sheathing, seal it too. This will ensure a good seal of one the caulk is compromised somewhere. If there are any penetrations through the sheathing for things like electrical, you have to seal all of that up too. No voids in surface density anywhere. Air tight. That’s the key to success. Greg

I hadn't seen any mention of donna conna (or donnaconna, one word) on here, which is sold as a soundproofing panel. I did a search for it, and it seems any time it's mentioned, it's from someone in my area, (the province of British Columbia in Canada) so it seems to be be a regional name brand. I worked at a hardware store that sold the product years ago, but it's almost impossible to find anything out about it online. What I can find about it describes it as a medium density fibreboard, but it's very different from the sheets of "MDF" that I also sold when I worked at the hardware store. Donna Conna you had to be more careful with, as it's very light and porous, very flexible, and you could break it with your hands if you wanted to. MDF was very hard, and stiff, no way you're going to break that. it doesn't look like anything in the fiberboard Wikipedia page. https://en.wikipedia.org/wiki/Fiberboard. it's hard to find an accurate close-up photo online, best I've found is here: https://tinyurl.com/uqukcdr This certainly seems like a good material to incorporate into my leaf construction. Thoughts?

Bretton M wrote:

I hadn't seen any mention of donna conna (or donnaconna, one word) on here, which is sold as a soundproofing panel. I did a search for it, and it seems any time it's mentioned, it's from someone in my area, (the province of British Columbia in Canada) so it seems to be be a regional name brand. I worked at a hardware store that sold the product years ago, but it's almost impossible to find anything out about it online. What I can find about it describes it as a medium density fibreboard, but it's very different from the sheets of "MDF" that I also sold when I worked at the hardware store. Donna Conna you had to be more careful with, as it's very light and porous, very flexible, and you could break it with your hands if you wanted to. MDF was very hard, and stiff, no way you're going to break that. it doesn't look like anything in the fiberboard Wikipedia page. https://en.wikipedia.org/wiki/Fiberboard. it's hard to find an accurate close-up photo online, best I've found is here: https://tinyurl.com/uqukcdr This certainly seems like a good material to incorporate into my leaf construction. Thoughts?

It sounds like you're describing soft board, or fibre board, or what most people round here call "homasote". It's basically a cellulose fibre type of panel that is used for pin boards, notice boards and sometimes an insulation. Here's a picture of it: We do use it as part of some sorts of acoustic treatment, mainly what we call "hangers" which are basically hanging waveguide absorbers. Although it may have been marketed as such in your hardware store, as far as I am aware it is not particularly great at soundproofing when used alone, especially at high SPL and low frequency. The first clue to this is what you said yourself: It's light. Greg, or anyone else for that matter, am I wrong about this? If so, I am happy to be wrong. For decent sound reduction you need mass. Either an absolutely huge amount of mass or smaller amounts separated by a single large air gap. There would certainly be no harm in using those soft board panels in conjunction with the usual drywall/OSB for example, it may even have some dampening qualities, but I would not waste it in a wall/ceiling assembly as it'd be much more effective just to use an extra layer of drywall in it's place. And the drywall would be cheaper too. Excellent isolation can be achieved with standard building materials. i.e. timber, drywall, OSB, insulation, caulk and concrete. It is the order in which you put those materials that makes the difference. Paul

I agree with Paul. I could see that stuff being decent as a flooring material as it might reduce some impact noise but I wouldn't waste my money or effort using it as wall or ceiling sheathing. In other news though, it could work great as a Homasote replacement. Can you call the hardware store you used to work at to see if it's still available? I'm personally interested in checking it out for building some hangers! Greg

Gregwor wrote:

I agree with Paul. I could see that stuff being decent as a flooring material as it might reduce some impact noise but I wouldn't waste my money or effort using it as wall or ceiling sheathing. In other news though, it could work great as a Homasote replacement. Can you call the hardware store you used to work at to see if it's still available? I'm personally interested in checking it out for building some hangers! Greg

Greg, after commenting on this thread it reminded me of a couple of other threads on here; have you read the homasote test thread on here as well as the other thread written by Steve from the Homasote company? It's quite interesting to see what he was saying about using homasote on one wall, on the cavity side seemingly having a small effect on TL and cavity resonance... however, it doesn't make sense and it seems the testing procedure must have been flawed. I like your idea of using it as part of a floor assembly, I believe this is indeed what it is used for the majority of the time for home building. It is strikingly similar to the thinner, green fibre based underlayment panels you can get (for very cheap). I wonder, if you were to double up those underlay boards so you have an overall thickness of 12mm if that would be a good alternative to actual homasote? I have seen it suggested on the hangers thread here. Might be worth the experiment considering those boards are really cheap (at least here in the UK). It's also interesting to note that Homasote at one time received a report stating that their product really has no acoustical benefits and yet we use them for hanger cores :D and it's also interesting that the main marketing slant of the Homasote company is that these boards achieve excellent sound proofing in both residential and commercial buildings :D they are extremely light in weight and quite porous, which really doesn't sound like a good sound proofing product. If I had the time and money I would love to build 3 identical rooms except one being constructed with 2 layers of drywall with green glue per wall, one with 3 layers of drywall per wall, and the other 2 layers of drywall with homasote in the middle per wall, I am interested in the potential damping qualities (or lack thereof) to airborne sound of the homasote when used in a sandwich, and whether or not it would be better than a 3rd layer of drywall. I doubt it myself, but it's all a big expensive unknown. I am also now wondering if there is a potential benefit of using the homasote up tight to the boundary, fronted with insulation and or the reverse. The homasote may have some sort of membrane effect to certain frequencies and would be good to experiment with that. I also have a whole tonne of it that I don't know what to do with.... Paul

Looking up Homasote, it does look like the same stuff. Most of the photos are a light tan, and I'm used to seeing it in a dark brown or black, but it otherwise it looks the same. I'm sure it's still available, any non-expert I talk to locally about how I'm soundproofing my garage says "oh, so you're going to put up some donna conna right?" with plenty of anecdotal evidence from people who have put it up and say it works. Because it's so light and porous, it seems to have the same properties as insulation, it would be very non-resonant.

If I had the time and money I would love to build 3 identical rooms except one being constructed with 2 layers of drywall with green glue per wall, one with 3 layers of drywall per wall, and the other 2 layers of drywall with homasote in the middle per wall

rather than a whole room, what about 3 small iso-boxes that a speaker could fit inside using those 3 different construction methods?

it's starting to look like a whole floating room is going to be outside my budget. I'm still waiting to hear back on how much some custom sliding doors will cost, but I'm guessing it'll be a few thousand. it looks like one layer of quietrock to cover the room, 37 sheets, would be about $2250, 24 bottles of green glue, about $500, and 20 bags of Rockwool insulation to reinsulate about $1250. so that's about 4,000 there, which will more than double if I have to do it all again with another wall, and of course that's not all I have to account for. with well made doors, how much isolation can I expect to get if I were to build up a single high mass airtight layer on the existing interior?

it looks like one layer of quietrock to cover the room, 37 sheets, would be about $2250, 24 bottles of green glue, about $500

Quietrock is basically drywall with Green Glue Compound already in between the sheets and packaged as a single unit. You wouldn't need Green Glue. However, you will need a caulk to seal everything. Please, do NOT use Green Glue Sealant!!! That stuff is honestly 100% useless. The Green Glue Compound is amazing stuff, but the Sealant cracks after a while no matter what. Stay away from it. I recommend DAP Dynaflex 230 in white around our area because it is cheap, easy to work with/clean up, and it actually works great!

with well made doors, how much isolation can I expect to get if I were to build up a single high mass airtight layer on the existing interior?

You can calculate the estimated isolation in decibels at any frequency you want using the formula below. 20*LOG(frequency*surface density in kg per square meter)-47.2 Sadly, with Quietrock, this formula wouldn't be accurate because the CLDM (Constrained Layer Damping Material) in the product will drastically change it's performance. They have charts on their website showing estimated performance. Greg

More budget items, got quotes in on doors, and quietrock. my custom sliding doors are going to be about 2000 apiece, with two entry points that those need to go on, one wall is 4000, two walls is $8000. One layer of soundproofing material as I've been planning it (37 sheets of quietrock, 20 bottles of green glue, and the supplier put in 7 units of CertainTeed SilentFX Putty) is 3700, so two of those is 7400. Already with one layer I'm at 7700, and with two layers 15,400. Add in the lumber, rockwool, silencer boxes, etc, and I'll definitely be clearing 20k to make a floating room. Trying to keep my anticipated budget to 10,000, with room to go up to 15,000 after unexpected costs get added on. a layer of cheap sheeting (OSB or cheap drywall) 600 Rockwool: 1200 has me up to $9200. Still need to figure out my silencer boxes, and will need to have some electrical work done. Is it worth it to rip the existing drywall and OSB off the walls to replace the pink insulation with Rockwool? or would I be just as well off to just start adding mass to the existing wall via quietrock? if I rip off the old drywall to put in rockwool, is it worth it to put a layer of cheap sheeting up before the quietrock? or just go straight to quietrock. should I be looking at those metal spacers to get a small air space between the studs, and a layer of mass, like isotrax or whatever brand name is in my area? also, how do I go about putting up the quietrock, and mounting the electrical outlets, the heater, and anything else we might want on the walls? Because we don't want to penetrate the leaf with screws right? just glue everything up? thanks.

my custom sliding doors are going to be about 2000 apiece

Care to share details about the brand, specs, etc? Those are cheaper than I anticipated which makes me question their quality.

One layer of soundproofing material as I've been planning it

Don't take this comment as being rude, but we never use the anything with the term "soundproof" in it around here because it implies that it is in fact possible to achieve silence and well, that's simply impossible. Words like isolation and transmission loss are the correct terms to use.

37 sheets of quietrock, 20 bottles of green glue

Green Glue is pricey and as I mentioned in my last reply, you don't need it. Maybe the person quoted you Green Glue Sealant and not Compound?

a layer of cheap sheeting (OSB or cheap drywall) 600

When it comes to drywall, luckily the heavy stuff we want is only $23.48 at Home Depot right now. CGC Firecode Core (Type X) 5/8-inch x 4 ft. x 8 ft. Drywall Gypsum Panel The "ultralight" which we don't want (heavier the better) is more expensive at $23.98. CGC UltraLight Firecode X 5/8-inch x 4ft. x 8ft. Drywall Gypsum Panel

Still need to figure out my silencer boxes, and will need to have some electrical work done.

These are both fairly expensive aspects for sure. Duct liner alone is wicked expensive and you can't just buy a little bit of it as it comes in big rolls.

Is it worth it to rip the existing drywall and OSB off the walls to replace the pink insulation with Rockwool?

It is not worth replacing the insulation. You can see in this picture that different insulation yields very small changes in isolation performances.

or would I be just as well off to just start adding mass to the existing wall via quietrock?

I wouldn't use QuietRock for beefing up your outer leaf. I would seal all of the stud bays with DAP DynaFlex 230, then use Green Glue Compound between the existing sheathing and a layer of 5/8" heavy drywall held up with cleats. Of course, apply a second layer of caulk after the drywall is up to ensure a great seal and fill any voids with the required surface density. Note, you'll need to move the cleats to a different position once the caulk is dry. Moving them will allow you to caulk where they were initially.

if I rip off the old drywall to put in rockwool, is it worth it to put a layer of cheap sheeting up before the quietrock? or just go straight to quietrock.

In order to get a worthwhile increase in isolation, you're going to have to rip off the old drywall in order to seal and beef up the existing outer leaf. As I pointed out above, cheap sheeting IS the stuff we want. Adding an extra layer of 5/8" drywall underneath the QuietRock would help for sure, but I wouldn't say it will make it a lot better. I'm guessing that you might gain a few dB more of isolation tops.

should I be looking at those metal spacers to get a small air space between the studs, and a layer of mass, like isotrax or whatever brand name is in my area?

Not if you want it to sound great in there. All of those devices have a weight limit which means it's really hard to safely mount acoustic treatment devices. Also, if you figure out the math and you can safely anchor the devices on the sheathing, you pretty much have to install a layer of OSB on the hat channel first so that you can freely mount your devices anywhere --> you still have to avoid putting any screw through spots that might have a stud or joist in the way. If you were to accidentally hit a stud or joist, ultimately you short out the system and completely ruin the isolation the clips+hat were supposed to provide. Also, the clips+hat systems are wicked expensive. Installation has to be done very very carefully.

also, how do I go about putting up the quietrock, and mounting the electrical outlets, the heater, and anything else we might want on the walls?

In an inside out build, it's great because you can run everything through the studs/joists just like a normal house build. The fabric you would put over the framing hides all of that and the outlets and things like that appear to be flush. If you don't do inside out, you have to surface mount everything because you cannot have any holes in your sheathing as that would ruin your isolation.

Because we don't want to penetrate the leaf with screws right? just glue everything up?

Screws are fine. Holes are not. Note: As I said above, if you're using resilient channel or clips and hat, you cannot put a screw where it has the potential to hit frame work! Greg

cool cool. Here are the quotes I got, this is all I know about the doors and what was included in the quietrock/greenglue quote: I certainly don't take any corrections as being Rude, that's why I'm here after all :lol: so please excuse my layman's term. for my "cheap sheeting" option, I was looking at 1/2" ultralight on homedepot.ca, and it's showing 14.48 a sheet, and 7/16" OSB is 15.20. so 37 sheets of either of those, I was rounding to $600. 23.48*37+12% gives me about $1,000 for a layer of firecode drywall. If I'm doing since I'm looking at one wall of construction now, are we still looking at the exterior sheeting, and the interior sheeting being the two leaves of a 2-leaf construction? I just removed the 3 exterior facing windows and boarded them up with OSB. in doing so I found that there's no house-wrap under the siding. I wonder if I should take the siding off and work on beefing up the exterior wall and sealing it from the outside, since I should be taking it off anyway to add the house wrap? I still need to beef up both sides of the wall, so I'll end up with OSB and firecode drywall with green glue in between, on both sides of the studs. Looks like quietrock is out of the budget. budget: doors: 5000 (also have the man-door to account for) firecode drywall: one layer outer, one layer inner, $2000 OSB, one layer inner: $600 green glue: one layer outer, one layer inner, $1000 vapour barrier: $100 Electrical: $? silencer boxes: $? DAP Dynaflex 230: 5.97 a bottle, not sure how many bottles I need insulation: (reuse existing) process: rip off existing drywall and OSB, pull insulation. install new doors Seal outer wall with Dynaflex add strips of firecode drywall with greenglue between studs pull all electrical wires to consolidate to one entry point. replace insulation sheet with OSB sheet with greenglue coated firecode drywall drill entry point for electrical have electrician run all electrical, surface mounted build silencer boxes drill entry points for ventilation mount silencer boxes caulk around electrical and ventilation ports am I just about ready to start working? *edit* I can't seem to find the instructions on how to calculate the size required for the silencer boxes, and how to construct them. I'm sure there must be a thread, could someone point me to the right one? I found Gregwor's silencer box with the algebraic dimensions, but how do I calculate the what X value I need?

I just messaged Bretton through social media but I'll recap a few things here for you all: I advised him to get the old school heavy firecode drywall instead of the ultralight stuff as we need mass here. For the outer leaf beef up, if you have to pull the siding to install barrier then 100% add the mass to the outside. It will take a fraction of the time and be sooooo much easier to do! I also recommended that he buy sliding doors designed by a company specifically to address sound isolation. The fact that his quote did not include any glass thickness specifications and seem to be constructed from plastic scares me. He said he just needs a good 4 foot wide opening to move gear in about might be pushing towards using a conventional door which would save him a lot of money. He needs 3 doors. 1 to separate inside spaces and 2 that will go outside. Does anyone have have recommendations about how to deal with a slab that will handle rain and such? Greg

I can't seem to find the instructions on how to calculate the size required for the silencer boxes, and how to construct them. I'm sure there must be a thread, could someone point me to the right one? I found Gregwor's silencer box with the algebraic dimensions, but how do I calculate the what X value I need?

Since plan to use the existing electric heater in the space and not worry about cooling, you only need to replace ~25-30% of the air compared to a ducted system. Needed flow rate = (at least 8 air changes per hour X cubic feet )/60 min 30% fresh air = Needed flow rate x 0.3 Once you know how many CFM you're pushing/pulling through your system, you can find out roughly how big the duct needs to be to hook up your inline fan by referencing a standard friction rate of .10 inches per 100 feet of lineal duct chart such as this: From there, you can calculate the cross sectional area of the duct. Here's a quick list to save you from doing the math yourself: Duct CSA: 4” RD duct = 12.57 sq in. Double = 25.14 sq in. 5” RD duct = 19.63 sq in. Double = 39.26 sq in. 6” RD duct = 28.27 sq in. Double = 56.54 sq in. 8” RD duct = 50.27 sq in. Double = 100.53 sq in. 9” RD duct = 63.62 sq in. Double = 127.23 sq in. 10” RD duct = 78.54 sq in. Double = 157.08 sq in. 12” RD duct = 113.1 sq in. Double = 226.19 sq in. Area of a rectangle = width x height Area of a oval duct = major radius x minor radius x π This is for a true oval, not a flat oval like HVAC duct though :-S Area of flat oval = π (minor radius)2 + [(major diameter- minor diameter) x minor diameter)] OR [(π minor 2) / 4] + 3 (major - minor) You can see in the list above that I've indicated what double the CSA would be. This is the minimum cross sectional area that the path inside your silencer box needs to be. If you could quadruple it instead of doubling it, that would be better. Just for fun, let's say you need a 10" round duct from your fan. Your box would then need to be at least 157.08 sq inches inside. So, if you had a simple square air path in your box, you could take the square root of 157.08 sq inches and end up with ~12 1/2".... let's be cool and increase that a bit to play it safe. So, 12 3/4" putting us at a healthy 162.56 sq inches. So, in the silencer box design image I made, 12 3/4" would be the value for "x". Also, we should make sure that our velocity is good coming out of the box into your room. In my 10" round duct example, let's say that the air velocity out each baffle will be 162.56 sq inches. In order to calculate the air velocity (which we need to be slower than 300 feet per minute), we need to convert our opening size from square inches to square feet. So, we simply divide our sq inches by 144 to get that value. 162.56 sq in / 144 = 1.1289 sq ft. So, to get the air velocity, we do this: 30% fresh air CFM / 1.1289 sq ft = velocity in ft per min If for some reason the air velocity is faster than 300 feet per minute, you will have to increase the size of the opening feeding your room. Or, if you have the space to have a bigger silencer box, simply make the entire thing bigger because it will also improve your insertion loss! Lastly, you have to find an inline duct fan to push or pull the air in/out of your room. To make life easier (for now until audiomutt, Chris, and I fine tune my static pressure calculator) I would recommend using 0.2 inches water gauge to spec out your fan. If you use a legit brand such as Fantech, their website has a calculator on it where you can enter your CFM and such and it will show you if the fan will perform as you need it to. Don't worry if the fan is slightly over spec as you can put a speed controller on it to slow it down. Greg

Progress report: Demo has begun: definitely not going to use any ultralight drywall, going for fire-code heavy stuff. Going to scrap the idea of sliding doors and go swinging. here's a shot of my heater to let that be known, going to just re-mount this once I've got the walls done: I don't remember getting too hot jamming in there last summer, but if I do, I was considering putting a window air conditioner in the garage next to this space, and ducting it through a silencer box into the space. This is before me knowing anything about ductless mini splits, so there's that to look into as well. looks like I'm dealing with 4865 cubic feet in there.

It's looking good so far, looks like you and greg have got things all figured out. Just a note of caution so you don't make the same mistake I did. How are you going to deal with ventilating your roof deck? Are you going to have a hot roof or cold roof? This important detail needs to be worked out early to avoid interstitial condensation forming on the under side of your roof deck and causing you to tear down all your hard work! Paul

Good timing! I'm about to start a similar build! Following this one for sure.

Gregwor wrote:

I For the outer leaf beef up, if you have to pull the siding to install barrier then 100% add the mass to the outside. It will take a fraction of the time and be sooooo much easier to do! Greg

Hmmm.. I just may go this route. I've got five windows to remove as well as beefing up my outer leaf on a 15x30 garage. I may just pull off all the siding and just beef it all up from the outside. This is what i'm working with regarding the outer leaf. Cedar siding on plywood, over plank walls.