Project home studio

[trickius]

Hello

i am just a step before starting my own home studio that will house an acoustic drums, 2 guitars, bass. With information mainly from your site i have come to this sketch (attached) that resembles a room in a room. However i am not sure about the wall i have to built in the left and bottom side of the sketch. I have a gap from the existing walls (brick or cement) in one side 90 cm and in the other 40 cm. I am not sure whether i have to go with a triple plasterboard>metal studs and insulation or triple plasterboard>metal stud and insulation>double plasterboard paying attention that i am not creating a triple leaf wall structure. Is 90 and 40 cm enough of a gap to allow me to built this kind of wall or is it considered a triple leaf?

Thanks a lot

[Gregwor]

I don't have SketchUp on this computer so I can't look at your file, however from your description I picked out these two conflicting points:

i have come to this sketch (attached) that resembles a room in a room.

triple plasterboard>metal stud and insulation>double plasterboard

The first point indicates that you want to build a room in a room. That means your inner room (the inner leaf) does not touch the outer room (outer leaf) whatsoever.

The second point describes your metal stud wall having drywall on both sides of it. That means your inner leaf and outer leaf are both touching via the metal stud. So this is not a room in a room.

I have a gap from the existing walls (brick or cement) in one side 90 cm and in the other 40 cm.

I wish I could open your file here. But I'm understanding that your outer leaf is brick or something like it. Your inner room should be built from wood or metal studs and then have a wooden inside out ceiling sitting on top of those new walls. I'm not sure what you mean by 90 or 40 cm.

I hope that helps for now. Sorry I couldn't open your file and tell you for sure!

Greg

[trickius]

I don't have SketchUp on this computer so I can't look at your file, however from your description I picked out these two conflicting points:

i have come to this sketch (attached) that resembles a room in a room.

triple plasterboard>metal stud and insulation>double plasterboard

The first point indicates that you want to build a room in a room. That means your inner room (the inner leaf) does not touch the outer room (outer leaf) whatsoever.

The second point describes your metal stud wall having drywall on both sides of it. That means your inner leaf and outer leaf are both touching via the metal stud. So this is not a room in a room.

I have a gap from the existing walls (brick or cement) in one side 90 cm and in the other 40 cm.

I wish I could open your file here. But I'm understanding that your outer leaf is brick or something like it. Your inner room should be built from wood or metal studs and then have a wooden inside out ceiling sitting on top of those new walls. I'm not sure what you mean by 90 or 40 cm.

I hope that helps for now. Sorry I couldn't open your file and tell you for sure!

Greg

Thank you for trying to be helpful. I am attaching a screenshot of the sketchup file that will clarify things a bit. It will still be a room in a room but out of those four walls, 2 sides are a little too far from the existing structure. One side serves as a corridor (90cm) while the other (45cm) is just a way to have access to the external window. Based on the formula that calculates vibrations on resonant cavities between newly formed drywall and existing brick/concrete wall i just try to figure if builting an inner wall of drywall/metal studs with insul./drywall will be considered triple leaf for those 2 walls.
The remaining two (top and right side) will consist of drywall/metal studs with insulation only. Those two inner walls will be 9cm apart from existing brick/concrete walls.

[Gregwor]

You will be fine as long as your inner room only has ONE sheathing mass.

Here are a few things you should consider as well:

- Your outer leaf needs to be completely air tight with no mass voids. That means, if there is any duct work or mechanical such as water lines, those need to be boxed over with enough mass to maintain your isolation needs. So, what that means is, I doubt you want to spend the time and money beefing up and sealing up the entire area to the left of your room. So, what you should do is build another wall to the left of your room to "box in" your inner room.

- Why do you need access to that outer window?

- What are you doing about HVAC? You need to find places to put your silencer boxes.

- This is purely a jamming room? Or a tracking room? You didn't mention mixing in your post.

Greg

Greg

[trickius]

Thank you for asnwering. Some more explaining

You will be fine as long as your inner room only has ONE sheathing mass.

Is a "sandwich" of 4 layers of drywall including mlv, metal studs with insulation and another 2 layers of drywall is considered one sheathing mass?

Here are a few things you should consider as well:

- Your outer leaf needs to be completely air tight with no mass voids. That means, if there is any duct work or mechanical such as water lines, those need to be boxed over with enough mass to maintain your isolation needs. So, what that means is, I doubt you want to spend the time and money beefing up and sealing up the entire area to the left of your room. So, what you should do is build another wall to the left of your room to "box in" your inner room.

So my plan of the "sandwich" above requires yet another wall? Building another won't be a requirement a second door for the rehearsal room? Also i am afraid it will narrow that 0.90cm corridor or it will short the rehearsal room some cm less.

- Why do you need access to that outer window?

This outer window is wired and connects with the house alarm. In any case that goes off or malfunctions i need to have access to check. Also that answers your next question, i need a space to run the hvac pipes that will exit from another small window left to that outer window that isn't included in my sketch. I will put the silencer boxes outside of the building.

- What are you doing about HVAC? You need to find places to put your silencer boxes.

- This is purely a jamming room? Or a tracking room? You didn't mention mixing in your post.

For the time being this will be a jamming room. I guess if it all turns nice later i will include the space to the left to build a mixing room.

Greg

Greg[/quote]

[Gregwor]

Is a "sandwich" of 4 layers of drywall including mlv, metal studs with insulation and another 2 layers of drywall is considered one sheathing mass?

The one side of your metal studs that has drywall and MLV would be considered one sheathing mass. You cannot have the other 2 layers of drywall on the other side of the metal studs otherwise you won't have a true decoupled MSM system.

So my plan of the "sandwich" above requires yet another wall? Building another won't be a requirement a second door for the rehearsal room? Also i am afraid it will narrow that 0.90cm corridor or it will short the rehearsal room some cm less.

You can't do your "sandwich" and achieve great isolation. You'll see on this picture that each wall only has sheathing on one side of it:

MSM-two-leaf-WallChunk-conventional--NOT-inside-out--one-room--S06.png

That is how you have to do your room. You could save space by building your inner leaf "inside out".

This outer window is wired and connects with the house alarm. In any case that goes off or malfunctions i need to have access to check. Also that answers your next question, i need a space to run the hvac pipes that will exit from another small window left to that outer window that isn't included in my sketch. I will put the silencer boxes outside of the building.

Your outer window needs to have the same surface density as the outer leaf sheathing. It also has to be sealed very very very well. Therefore, it will never open. I'd replace that window with proper glass (laminated) and reprogram the alarm to ignore that sensor.

For your silencer boxes, you could have your OUTER leaf silencer boxes outside, but where are your inner leaf boxes going to live?

For the time being this will be a jamming room. I guess if it all turns nice later i will include the space to the left to build a mixing room.

Excellent. So with jamming volumes, I assume you're going to need great isolation. So a proper decoupled room in a room type construction.

Hopefully all of my answers have made sense!

Greg

[trickius]

Thanks Gregwor,

your sketch is self explanatory. I will try to redesign to match it. Also the hvac i will run the pipes out of the decoupled room but inside of the outer walls. After a couple of turns i will run them outside out of the window to the silencers. The motors i plan to have them outside after the silencers.

[Gregwor]

Also the hvac i will run the pipes out of the decoupled room but inside of the outer walls.

These can't be pipes. They have to be "sleeves" made out of the same material as your silencer boxes (typically something with the equivalent surface density as your leaf sheathing such as 1" MDF). So you're going to have all four silencer boxes between your leaves? This is a great idea but I'm not sure if you understand just how large these boxes are!

After a couple of turns i will run them outside out of the window to the silencers.

Each silencer box should have at least 3 baffles in them. These are the only necessary turns to achieve decent insertion loss.

I still don't understand how you are going to run the silencer box sleeves out of your windows. So you are going to fill in the wall where there is a window but cut holes to run the sleeves through?

The motors i plan to have them outside after the silencers.

You typically only have one motor. Most people put them on the return side of the system to pull the air through the room and spit it out.

Greg

[trickius]

Each silencer box should have at least 3 baffles in them. These are the only necessary turns to achieve decent insertion loss.

I still don't understand how you are going to run the silencer box sleeves out of your windows. So you are going to fill in the wall where there is a window but cut holes to run the sleeves through?

I have changed the plan according to your advice, i will shut (or remove) the outer window and fill it with drywall from the outside. So no inner window as well. There will be enough space in the outer window cavity to fill with 3 or 4 drywall layers. The window is 1.8x1.2 meters so i will have the inside of the window up to my inner wall a measurement of 9 cm and additionally 11 cm (so total 1,8x1,2x0.20) to put my silent boxes there. Then i will run the pipes after the silent boxes through the 3 or 4 drywall layers outside and in the motors. If there is still noise coming out i will put another silent box outside.

You typically only have one motor. Most people put them on the return side of the system to pull the air through the room and spit it out.

can you point me a design of what you're saying here?

[Gregwor]

I have changed the plan according to your advice, i will shut (or remove) the outer window and fill it with drywall from the outside. So no inner window as well.

Windows are fine if you have the money to spend on glass. But no windows makes for an easier build for sure.

There will be enough space in the outer window cavity to fill with 3 or 4 drywall layers.

Drywall installed on the exterior of your building is not good. You need to follow typical building code for this. Also, the sheathing only has to match the surface density of the rest of the outer leaf. If that means 4 layers of drywall, then sure. If not, you're just putting extra there for no reason.

The window is 1.8x1.2 meters so i will have the inside of the window up to my inner wall a measurement of 9 cm and additionally 11 cm (so total 1,8x1,2x0.20) to put my silent boxes there.

So a total of 20 cm? I doubt that is enough space to fit a silencer box.

Then i will run the pipes after the silent boxes through the 3 or 4 drywall layers outside and in the motors.

You have to penetrate the wall with the "sleeve" of the silencer boxes. The window is large enough you should be able to make that happen but I am concerned with your 20 cm of gap only. Also, you're implying that you'll be using motors (plural) instead of one motor.

If there is still noise coming out i will put another silent box outside.

This is simple to determine. If you already know that you need a room in a room construction to achieve your required level of isolation, then you need a total of 4 silencer boxes. One for supply and one for return on BOTH the inner and outer leaf. You could put your inner leaf silencers in your wall cavity and your outer leaf silencers outside.

can you point me a design of what you're saying here?

Just put one fan/blower at the exhaust of your outer leaf return silencer. So, at the very end of the system. That's all you need, presuming you size it correctly.

Greg

[trickius]

Thanks Greg, considering your advice i will built 4 silencer boxes and put them in and out of the studio. Not between the layers in the window. Also i will use one fan only in the exhaust. The inlet will use the pressure difference to suck air in.

[trickius]

I'm back again having start the construction. From early start i think i've made a grave mistake.

Instead of first laying the inner walls and later build the floating roof between those walls (without touching) i have laid the floating ceiling first in order for the inner walls to been built under this ceiling. In this way i think i have condemned the use of the floating roof altogether even though the room within a room idea is still valid.

Should i try to remedy that and cut through the plasterboard in order to fit the walls or i should accept my fate and try to do my best living with it?

To be precise i think the ceiling will still be decoupled but not floated any more

[Gregwor]

Yikes. The only way to achieve great isolation is to not have the walls or ceiling of your inner room touch the outer shell, period. What you're describing completely destroys that and I'm sorry to say that even if you build your walls decoupled, your isolation is pretty much as good as it is going to get at this moment because your ceiling is flanking the outer shell and will transmit sound throughout the structure. If I were you, I'd yank out that ceiling, draw your entire build in SketchUp so that you don't make a mistake like this again. It sucks, but in my opinion there is no point in continuing your build if it isn't going to perform the way you need it to.

Greg

[trickius]

Yikes. The only way to achieve great isolation is to not have the walls or ceiling of your inner room touch the outer shell, period. What you're describing completely destroys that
Greg

no no let me explain my case better. The ceiling isn't touching the outer shell. I 've made two sketches (sketchup would take me a century) that describe what i was planning to do vs what i later discovered would be better.

the initial plan first

20190428_111637_2.jpg

and the revised plan second

20190428_111648_1.jpg

[trickius]

I left the floor out of the sketch intentionally. But it will be built in a similar way like beeros05 did it link