Garage Studio Design - Internal layout and concept

[shineyd]

Hello,

I am embarking on a studio construction project in the garage of my property.
Phase 1, was the extension of an existing garage to provide as much real estate as possible. Now this is complete, I am ready to being the plans for the internal structures and layout.

The main use of the space, will be as a mixing suite. So a good size and sounding control room is key. I would also like to have the luxury of tracking a drum kit in it from time to time, so a high level of isolation is required.
The second most import requirement is storage. It doesn’t need to be pretty, but the apex of the roof would need to be accessible for storage of both household items (gear) and music gear (more gear)

Construction:
Single layer block-work, on 600mm foundations 1000mm deep. 150mm concrete slab poured internally to walls.
Roof is supported by steel beam, completely vaulted internally. Thermal insulation has been installed between roofing tiles, and boarding illustrated in pictures. This can be removed if necessary, however it is not intended to provide any form of acoustical isolation.
The structure/foundations/slab etc, is not attached to any other buildings, and located ~15m from any other structures.
No windows, and the entrance door is uPVC.
Walls 2200mm from floor
Steel Beam (lowest point of internal pitch) 3200mm from floor

Internals.jpg

Site Plan.png

Proposed layout:
Control Room, measuring approx 5000 x 3500 (based on 1:1.6:2.33 Sepmeyer ratio found in Rod Gervais book, actual dimensions will be closer when plans are finally drawn out)
Isolation Booth/Vocal Booth measuring approx 2500 x 1000

Both ~2200mm high, constructed as free standing, timber frame. Air gap to external wall, cavity filled with insulation, and 2 layers of plasterboard internally.
In my drawings/mockups I have allowed for 300mm of insulated wall assembly.

Layout Plan.png

Goals:
Control room will be used mainly for mixing. However, I will from time to time record a drum kit from this space. I want to aim for the highest level of isolation possible. I’m not able to give numbers here (sorry), but I am aiming for the sound of a drum kit to be inaudible by neighbours in the adjacent garden.

Isolation booth will be used for recording guitar cabs turned to 11. It will also function as a vocal booth, however this will be rather infrequent.


As the picture illustrates, I have not begun any of the internal work. As such I am not committed to any plan of attack, other than the obvious: Most return, for the lowest cost. I am under no illusion that this project will be expensive, and I am very much of the opinion that if you are going to do a job, you should do it once and do it properly. I also fully acknowledge that there are many gaps in my knowledge, which is why I intend on reaching out to this forum quite a bit. To begin with, I wanted to ask these two questions first.

1. As the concrete slab is not connected to any adjacent structure, do I need to have a de-coupled studio floor? My reading so far has suggested that a floating floor is both difficult to implement properly, and in many cases unnecessary. Not to mention the fact that it will eat into the little height I have available to me.
If I construct my stud walls by attaching them to the slab, and build my ‘isolated room’ on this same slab, have I in affect bypassed the isolating properties of a MAM wall system by maintaining a flanking path from - Internal floor to external wall.
OR is the essential mass of the whole floor system so great, that it negates this?


2. As I intend to use the “attic space” as storage, which would require me to board the roof of the 2 rooms. Do I need to approach this as though I were building an isolated floor for a sound-proof room, ie decoupling this attic space floor, from the wooden frame room structure below? Baring in mind I am only concerned with sound escaping the garage building as a whole.
I have read through the studio construction book by Rod Gervais, and the section on wall construction talks about how removing 1 layer of drywall from the outside of an assembly increases the STC. If I were to put floor boarding on the other side of the roof structure, have I robbed myself of isolation?
An associated point here is to the “airlock”. Does this space have to be truly isolated? In my suggested plan, this area is open to the storage areas in the roof.


Thanks for reading,
Any help, suggestions, blindingly obvious points I’ve missed, please let me know!
James

[Gregwor]

1. As the concrete slab is not connected to any adjacent structure, do I need to have a de-coupled studio floor? My reading so far has suggested that a floating floor is both difficult to implement properly, and in many cases unnecessary. Not to mention the fact that it will eat into the little height I have available to me.
If I construct my stud walls by attaching them to the slab, and build my ‘isolated room’ on this same slab, have I in affect bypassed the isolating properties of a MAM wall system by maintaining a flanking path from - Internal floor to external wall.
OR is the essential mass of the whole floor system so great, that it negates this?

Unless you have a ton of money and need insane isolation, the slab as is will be fine.

2. As I intend to use the “attic space” as storage, which would require me to board the roof of the 2 rooms. Do I need to approach this as though I were building an isolated floor for a sound-proof room, ie decoupling this attic space floor, from the wooden frame room structure below? Baring in mind I am only concerned with sound escaping the garage building as a whole.
I have read through the studio construction book by Rod Gervais, and the section on wall construction talks about how removing 1 layer of drywall from the outside of an assembly increases the STC. If I were to put floor boarding on the other side of the roof structure, have I robbed myself of isolation?
An associated point here is to the “airlock”. Does this space have to be truly isolated? In my suggested plan, this area is open to the storage areas in the roof.

Your attic space will almost for sure be occupied by your HVAC silencer boxes. Your airlock area is part of your outer leaf and would for sure need to be sealed, yes. Where would your air handler live (or maybe you will use a mini-split?)

Greg

[shineyd]

Hi Greg,

Thanks for your response, and apologies for the delay in my reply. Work has become increasingly busy over the summer!

Your attic space will almost for sure be occupied by your HVAC silencer boxes. Your airlock area is part of your outer leaf and would for sure need to be sealed, yes. Where would your air handler live (or maybe you will use a mini-split?)

My thoughts with the air handling, was to have a system whereby the 2 isolated rooms are ventilated into the ‘airlock’ area, and this is then ventilated to the outside. Would this enable me to have smaller silencer boxes as there is essentially 2 stages of isolation between the noisy environment and the outside world?

With regards to the outer leaf, would ‘inside-out’ style construction be suitable here?:

Concrete Blockwork | 2 x layers plasterboard | rock wool insulation between timber studs

This would cover all the walls and the internal roof area.

Just to link back to my first post, I have every intention of providing figures for the actual levels of attenuation required, however I am unable to do any work at my property until early autumn. I have purchased an SPL meter, just need to get home with it!

Best
James

[Gregwor]

My thoughts with the air handling, was to have a system whereby the 2 isolated rooms are ventilated into the ‘airlock’ area, and this is then ventilated to the outside. Would this enable me to have smaller silencer boxes as there is essentially 2 stages of isolation between the noisy environment and the outside world?

I recommend reading a bunch of threads on the forum and see how people have dealt with silencer boxes. Unfortunately I don't see how your plan would work in the real world. Each leaf's sheathing has to be penetrated by the silencer box sleeve. The inner and outer leaf silencer boxes are then joined by some air tight flexible material such as rubber, fabric or something as simple as flex duct.

Your plan also does not address heating/cooling. Options are forced air sytems or ductless mini splits. Ductless mini splits require less space as you only have to remove/replace ~30% of your required room CFM for fresh air. This means smaller ducts and smaller silencer boxes. But, then you have a large condensor hanging off your wall.

With regards to the outer leaf, would ‘inside-out’ style construction be suitable here?

Your outer leaf is the concrete. So just make sure it's sealed and you're good to go with it. For your INNER leaf, inside-out is always desirable.

Greg

[shineyd]

Hi Greg,

Again, apologies for the delay in my reply.

I recommend reading a bunch of threads on the forum and see how people have dealt with silencer boxes.....

Copy that

Your outer leaf is the concrete.

How would this apply to the roof? The wooden boarding in the picture is going to be removed as it was not installed particularly well, this will leave the roofing felt/tiles above. In order to prevent air gaps etc, would a layer of plaster board (or 2) suffice?
Is there anything I would need to do to the concrete block-work? Sealing paint etc….

For your INNER leaf, inside-out is always desirable

Would this not leave me with internal walls that have no surface to mount sockets etc?

As always, many thanks for your time
James

[Gregwor]

Again, apologies for the delay in my reply.

I've been so swamped with work/life that I haven't had much time to spend on the forum either, so no worries!

How would this apply to the roof? The wooden boarding in the picture is going to be removed as it was not installed particularly well, this will leave the roofing felt/tiles above. In order to prevent air gaps etc, would a layer of plaster board (or 2) suffice?

You need sealed appropriate surface density sheathing for your roof. There are many different types of roof construction but often you need your roof to be breathable with outside air. In my personal build, my live room is garage. The "attic" portion of the garage is breathable. So, my outer leaf will be drywall/OSB fixed the the bottom of the joists. Then, my inner leaf ceiling will be below that. I hope that helps with your situation.

Is there anything I would need to do to the concrete block-work? Sealing paint etc….

Yes, seal it.

Would this not leave me with internal walls that have no surface to mount sockets etc?

Your electrical should be surface mounted. Fix boxes to your inner leaf studs and if you want a flush look, just put fabric on the face of your wall.

Greg