Backyard practice space/studio from scratch on pad

[Seandoe]

Hello!

I've been a long time reader for a while, and this forum was a great resource when I put together a RiaR practice space in the basement of my previous house. I have recently moved into a new house and intend on building my dream practice/jam/hobby studio space on a an external garage/shed slab in my back yard, so I'm making my first post to get some advice so I don't have any regrets down the line.

Pertinent info:
- 38 x 22 ft. slab is already in place, with power running to it, but nothing has been built on it so far. It's a clean slate.
- Roughly 10 x 12 ft of the inside of this thing needs to be devoted to being an actual shed to house our lawnmower and such. Which will be accessible from the outside through a separate door.
- Besides the shed area, I'd like to maximize every inch of the remaining space to it's best potential.
- Didn't know how to get it included in sketchup, but I plan on using electric baseboard heat. Eventually I plan to have a mini-split AC in the main room and control room. I plan on using an HRV system for ventilation (with silencer boxes).
- This is just intended to be a hobby/fun jam space to be used by myself and family/friends, definitely not a commercial or even secondary income source studio (you'll note no bathroom included in design).
- Typical music being played will be indie/rock music with live drums, etc....I'm planning for 100-110db inside.
- Closest neighbor of concern's house 80 ft+ to closest corner of slab.
- Basically 100% of the labor will be done by myself/family/friends.
- I apologize in advance for my sketchup drawing. I had never used the product before, and even that sad design took me days to complete. I have an architect friend who can help me put something better together, but I at least want to get the plan on the forum.
- It should be in my profile, but this is in North Dakota, USA.

Issues/questions:
1. In general, I'd like to just get some more eyes and input on my current design. In a perfect world, I'd like to have a control room, as big of a live room as possible, and at least 1, if not 2, extra small but functional iso rooms. They will largely serve as storage to keep the other rooms clean of stands, guitar and gear cases, amp covers, etc, but will work as functional iso booths when I'm recording. I'm thinking 10 ft walls on the outside of the structure. As I said, I'd like to make the most use of the space. The only room I was able to make sure was in the "bolt area" was the control room (assuming 8.5ft ceiling). If possible, I'd like to vault the ceilings in the live room. The rough dimensions of the main walls live room put it at nearly a square, which I know is definitely not ideal. I was wondering if at roughly 21 x 20 ft, with the two iso booths and the vaulted ceilings, it would be large enough, and weirdly shaped enough to not be TOO damaging at those dimensions, once some room treatment is in there.

2. Understandably, there seems to be a fair amount of info available on helping to beef up your outer leaf when building a room in a room in an already existing structure, but I can't seem to find as much when building from scratch. I know in Rod's book it talks about cutting sheetrock to fit into the cavity between the studs, and somewhere online he had posted a good way to save some money is to cut out the existing sheetrock already on the wall to be pushed back in. This is what I did at my old house when I did a room in a room of a bedroom to make a practice space, and it was honestly the worst/most tedious part of the project. Is this still what would be suggested to do, or are there quicker/easier/more effective methods that could be done when building from scratch that won't break the bank?

3. Semi-related as far as the outer wall of the house, are people now suggesting doing zip system sheathing and tape, or is it not worth the extra expense? Better or more effective suggestions?

4. Getting back to the vaulting of the ceilings, is there any rule of thumb or conventional wisdom as far as size or spacing of the ceiling joists of my "inner" ceiling that would definitely support the 2 layers of 5/8" sheetrock?

I'll leave it at that for now to get started. Any info would be greatly appreciated!!

Thanks!

(Note: If it would help, I can provide current sketchup file. It's telling me it's too big to upload the compressed file here)

[Soundman2020]

Hi there " Seandoe", and Welcome!

- 38 x 22 ft. slab is already in place, with power running to it, but nothing has been built on it so far. It's a clean slate.

Wow! That's a really nice sized slab, and a rather ambitious studio for a backyard! Clearly, you've already put quite a bit of thought into this.

- Roughly 10 x 12 ft of the inside of this thing needs to be devoted to being an actual shed

Fine, but you are missing the isolation walls around that area, that divide it from the actual isolated studio space. The shed doesn't need to be isolated, and you can't put a room in your air gap, so you do need to complete the isolation shell.

... I plan on using electric baseboard heat. ... Eventually I plan to have a mini-split AC in the main room and control room. I plan on using an HRV system for ventilation (with silencer boxes).

I would really, really, really suggest that you consider adding a proper HVAC system (which can certainly include an HRV, to save on operating costs), for the simple reason that you need to keep your humidity under control, and an HRV won't do that. It just transfers heat from one air stream to another. An proper ducted AHU mini-split system is many, many times more energy efficient than a baseboard heater, since it uses the principal of liquid/gas phase change to move heat from one place to another with great efficiency. You'll save a lot of money over time, since your heating and cooling costs will be way lower than what they would have been with purely restive electrical heating, which is not very efficient at all, and also does not control humidity.

There are many other very good reasons for doing the right thing and installing a proper HVAC system form the start, but just saving money seems like a great reason to start with!

- This is just intended to be a hobby/fun jam space to be used by myself and family/friends, definitely not a commercial or even secondary income source studio (you'll note no bathroom included in design)

Your family and friends are fortunate indeed to have you around, to build a place like that just for their benefit!

- Typical music being played will be indie/rock music with live drums, etc....I'm planning for 100-110db inside.

Right. That's a realistic estimate.

- I apologize in advance for my sketchup drawing. I had never used the product before, and even that sad design took me days to complete.

If you came up with that after just a couple of days on SketchUp, from a total newbie start, than I take my hat off to you! It's a great product, very powerful, but it does have a steep learning curve. Getting that far in a couple of days is pretty darn good!

extra small but functional iso rooms. Thich will largely serve as storage to keep the other rooms clean of stands, guitar and gear cases, amp covers, etc, but will work as functional iso booths when I'm recording.

You could do that, but I'd honestly suggest that it would be way better to have a small storage area instead, so you can use your booths as booths, without needing to move piles of junk in and out each time you want to track a vocal or guitar cab. It seems rather strange to go to all the trouble of isolating a room carefully, and putting special-purpose carefully crafted acoustic treatment in it, then filling it with junk...

I'm thinking 10 ft walls on the outside of the structure.

That's a good start, but if you can go higher, then that would be better. Music and sound love space and air, so the more space and air you can put inside, the better.

If possible, I'd like to vault the ceilings in the live room.

It should be possible, yes.

it at nearly a square, which I know is definitely not ideal. I was wondering if at roughly 21 x 20 ft, with the two iso booths and the vaulted ceilings, it would be large enough, and weirdly shaped enough to not be TOO damaging at those dimensions, once some room treatment is in there.

It's fine. No problem. It will still need treatment in any case, so that's not an issue.

2. Understandably, there seems to be a fair amount of info available on helping to beef up your outer leaf when building a room in a room in an already existing structure, but I can't seem to find as much when building from scratch.

Simple! Just layer up the outside to get the mass you need on the outer-leaf, directly on the studs! For example, put thick OSB on the studs, for both structural purposes (sheer) and acoustic purposes, then perhaps a layer of fiber-cement board for extra mass, then whatever finish you want over that. Or maybe stucco. OR for even more mass, start with two layers of thick OSB with Green Glue in between, then your fiber-cement board (also with Green Glue in between). Lots of options. You could even do brick, or concrete block for the outer-leaf wall, to really get a lot of mass on there.

cut out the existing sheetrock already on the wall to be pushed back in. This is what I did at my old house when I did a room in a room of a bedroom to make a practice space, and it was honestly the worst/most tedious part of the project. Is this still what would be suggested to do, or are there quicker/easier/more effective methods that could be done when building from scratch that won't break the bank?

The only reason for doing that is when you already have an existing wall, and you can't add more mass to the other side for whatever reason. In your case, you are free to add as much mass as you want to the "other side" right from the start, so you don't need to bore yourself to tears and shred your hands with all that strip-cutting, caulking, and cleat nailing....

4. Getting back to the vaulting of the ceilings, is there any rule of thumb or conventional wisdom as far as size or spacing of the ceiling joists of my "inner" ceiling that would definitely support the 2 layers of 5/8" sheetrock?

Oh yes, absolutely! The joists have to be dimensioned correctly to span the distance between the walls while supporting the full dead load and live load, with the correct maximum deflection. That depends on many things, but there are span tables and span calculators that you can use to estimate that: However, you really shout get a structural engineer to check that, to make sure it is safe and meets code. You don't want thousands of pounds of ceiling to come down on your head the first time you use the room!

I would also suggest that you do your ceilings "inside-out", for all the benefits that gives you. It's harder to build, yes, but the benefits make it worthwhile.

ll leave it at that for now to get started. Any info would be greatly appreciated!!

I'd also suggest turning your control room around the other way, so that it faces towards the live room, and put a window in there, for good sight lines between rooms.

But overall your plan looks pretty good. It just needs refining.


- Stuart -

[Seandoe]

Hello studio design community,

First, I wanted to thank Stuart for his in-depth response to my initial post, and apologize for not responding for a year. Since we were coming into fall, we decided to focus on finishing our yard and putting up a fence before winter. Over the winter I built an attic space and finished our garage. We also welcomed a new baby girl to the family, which has been keeping us busy for the last several months. I'm finally ready to dive back into this project.

I'm including an updated, more realistic, draft of a design with this post. Continued input and suggestions are welcome.

To quickly address some of the points raised in Stuart's response.

Fine, but you are missing the isolation walls around that area, that divide it from the actual isolated studio space. The shed doesn't need to be isolated, and you can't put a room in your air gap, so you do need to complete the isolation shell.

I see. Since I wasn't concerned with sound going in/coming from the shed portion, I wasn't aware that the shed portion couldn't basically just be thought of as a large air gap. In my updated design I have it planned for the second isolation wall between the shed part and the control room/iso booth.

I would really, really, really suggest that you consider adding a proper HVAC system (which can certainly include an HRV, to save on operating costs), for the simple reason that you need to keep your humidity under control, and an HRV won't do that. It just transfers heat from one air stream to another. An proper ducted AHU mini-split system is many, many times more energy efficient than a baseboard heater, since it uses the principal of liquid/gas phase change to move heat from one place to another with great efficiency. You'll save a lot of money over time, since your heating and cooling costs will be way lower than what they would have been with purely restive electrical heating, which is not very efficient at all, and also does not control humidity.

Understood. I've started trying to do the initial calculations needed for the room size/equipment i have/number of people who will normally be in there/etc. I'm sure I will have many more questions involving the actual placement and integration of a ducted system into my design. And will have questions on what will be the most cost effective units to achieve the desired results. As for now, you will see that I have a section of the shed area roomed off to be some kind of mechanical room/exchange chamber. More on this to come later, I'm certain.

I'd honestly suggest that it would be way better to have a small storage area instead, so you can use your booths as booths, without needing to move piles of junk in and out each time you want to track a vocal or guitar cab. It seems rather strange to go to all the trouble of isolating a room carefully, and putting special-purpose carefully crafted acoustic treatment in it, then filling it with junk...

That really does make more sense. I didn't get it finished on the draft posted below, but the redesign i did drops the idea of 2 iso booths. What is shown now as one long iso booth is going to be divided into a roughly 6'x5' iso booth into a roughly 5'x5' storage closet/mic locker. This can hold the items that I will regularly want to get at. Still playing with the exact dimensions of those rooms (and effectively the width of the control room) by deciding how much space I want to eat up from the live room. There will be ample space to store bigger/rarely used items in the shed portion of the building and/or my garage/attic, which is only a few feet away from the slab!

That's a good start, but if you can go higher, then that would be better. Music and sound love space and air, so the more space and air you can put inside, the better.

Probably seems like common sense to others, but when pricing out the initial "outer shell" materials, I was surprised to find that it was actually cheaper to build at 12 foot walls with common trusses than it was to build at 10 foot walls and vault the ceiling. By code, the highest the walls can be is 12 feet. So that's what it's going to be.

I would also suggest that you do your ceilings "inside-out", for all the benefits that gives you. It's harder to build, yes, but the benefits make it worthwhile.

I somehow hadn't heard of this before. I'm looking into it and trying to wrap my head around it. Especially how it seals up with the inner leaf wall. We're pretty handy, but it could outside of our ability to pull off. I'll keep researching. Just curious, since you didn't mention this for the walls, is it not something you want to do for the ceilings AND walls? If only doing one of them, does if offer greater benefits for the ceiling?

I'd also suggest turning your control room around the other way, so that it faces towards the live room, and put a window in there, for good sight lines between rooms.

Please see my new design on room orientation. I'm including a mic/storage closet (half of what's shown as the now single iso booth), and a preliminary idea for a space for HVAC. Also, my original design would've meant going through an iso booth to get to the control room AND had the control room door in the back corner. The redesign would just have the door going into the side of the control room. I'm really torn on exactly where to put the wall between the live room and control room to maximize the potential/usefulness of both rooms. Input would be appreciated!!

Since my layout is now basically just a live room and a control room (with basically just a guitar cab iso room), I had intended on using video monitors and cameras for room views from control room and live room. I thought that would maximize isolation and be easier, if not also cheaper, than trying to put in a functional and soundproof window.

But overall your plan looks pretty good. It just needs refining.

Thanks! Hopefully my changes make even more sense.

As I've been doing more work and research on this, my most recent question I've come up with in relation to building the "outer shell" from scratch is how to actually get the ceiling of the outer shell sealed up? Specifically the under side of the roof overhang. I'm a little confused how that is supposed to be enclosed. What I came up with would be to sheetrock the under side of the trusses and seal that to the inside of the wall 2x6s? That would seem much easier, but then once I have my separate inner rooms, aren't a making a triple leaf between my inner room ceilings, outer shell "ceiling", and the actual roof of the building? Sorry if this doesn't make sense. I can try to be more clear if not.

Any help on that would be great! And any other input anyone sees would be super appreciated!!

Thanks!

Sean

[Seandoe]

Most current design:

Studio Top - New.jpg

Studio Side - New.jpg

[Seandoe]

Also, in the mean time, I've tried to do the isolation calculations for my current plan, which includes 5/8ths osb with fiber cement panel siding on top for the outer shell, and 2 layers of 5/8s sheet rock on the inside of the rooms. I'd really appreciate a second set of eyes to make sure this looks right and give an overall opinion. As I stated the closest neighbor house of concern will be about 80ft away from this slab.

MSM calc.

Fc = c[(m1+m2)/(m1*m2*d)]^.5

Outer wall - 5/8" OSB - 2.0 psf + Fiber cement siding - 2.46 psf = 4.46 psf or 21.77 kg/m^2 = m1
Inner wall - 5/8" sheetrock - 2.31 psf x 2 (double layer)= 4.62 psf or 22.56 kg/m^2 = m2
Distance between leaves - 5.5"(2x6 outer wall) + 1"(wall gap) + 3.5" (2x4 inner wall) = 10" = 0.83 ft or 0.254 m = d

Fc=resonance frequency (Hz)
c=constant (60 for empty gaps and 43 for with insulation)
m1=mass of first leaf (kg/m^2)
m2 mass of second leaf (kg/m^2)
d=interleaf spacing (m)

f0 = c[(m1+m2)/(m1*m2*d)]^.5
f0 = 43[(21.77+22.56)/(21.77*22.56*0.254)]^.5
f0 = 43[44.33/124.75]^.5
f0 = 43(0.355)^.5
f0 = 25.62 Hz

R = 20log(f(m1 + m2)) - 47(where f<f0)
= 20log(26(21.77 + 22.56) - 47
=20log(26(44.33)) - 47
=20log(1,152.58) - 47
= 61.23 - 47
= 14.23 dB - iso below reso.

Between reso and coincidnce:

R1 = 14.5 log (21.77*0.205) + 23db
R2 = 14.5 log (22.56*0.205) + 23db

R1 = 9.42 + 23db = 32.42
R2 = 9.644 + 23db = 32.644

R = R1 + R2 + 20log(fd) - 29(where f0<f<F1)
R = 32.42 + 32.644 +20 log (26 * 0.254) - 29
= 32.42 + 32.644 + 16.396 - 29
= 52.46

It would be easier for me to work in feet, but curiously, I get a radically different beginning frequency calculation. I'm assuming I must be making some calculation or conversion wrong right away, but I can't spot the error....

For imperial units the constants are 170 and 120.

f0 = c[(m1+m2)/(m1*m2*d)]^.5
f0 = 120[(4.46+4.62)/(4.46*4.62*0.83)]^.5
f0 = 120[9.08/17.17]^.5
f0 = 120(0.5288)^.5
f0 = 120(.727)
f0 = 87.24 Hz???

[Soundman2020]

For imperial units the constants are 170 and 120.

f0 = c[(m1+m2)/(m1*m2*d)]^.5
f0 = 120[(4.46+4.62)/(4.46*4.62*0.83)]^.5
f0 = 120[9.08/17.17]^.5
f0 = 120(0.5288)^.5
f0 = 120(.727)
f0 = 87.24 Hz???

No. The constant does not change. It is still 60 for empty gaps and 43 for with insulation, exactly as I gave it. I don't understand why you changed it to 120.


- Stuart -