Advice on soundproofing garage with enormous ceiling height

[janwesterm]

Hi everyone and greetings from Greece!

I want to build a non professional rehearsal space for my band which will also serve as daily practice room for me as a drummer. This concerns mainly sound leaks and not sound treatment (which I will deal with later).

The space I have available for this is a double garage on the ground floor (no basement underneath), with concrete walls and floor. One wall is shared with a neighboring house. The ceiling is very tall, at almost 5 meters, above that there is an apartment, and the front, facing to the street is generally a bit leaky, as it is aluminum framed glass. (Typical garage/store in Greece). The other 2 walls are not an issue.

I want to achieve maximum isolation for the one wall with the neighboring house and the glass front as well as the apartment above. Low frequencies are expected in form of Bassdrum.

I want to build a free standing room on a floating floor within this existing space but due to the specific circumstances of the tall ceiling and the leaky original structure, I am asking for advice and hope I can get some input from you.

I am attaching a Google Street View Photo of the Garage, which is the one with the "No Parking" sign. You can see the neighboring house and the apartment on top.

My specific questions are:

1. Do you have any advice on how to construct the ceiling for the free standing room to achieve maximum isolation for the apartment above? I obviously will have the ceiling constructed floating on the studs of the new room structure, but would you consider a single leaf ceiling and count the original ceiling as second leaf? The gap between those 2 ceilings would be at almost 2 meters. Does this even count as air cavity that we talk about when discussing soundproofing, as it will be enormous and a lot bigger than the air cavity between the walls?

2. As I mentioned, the existing structure is a bit leaky by itself, especially the front. Can I even consider the existing wall structure as a leaf for creating an air cavity? Is it preferable to seal up the glass front (with a door, there is an alternate entrance in the back which I could use) with plasterboard to be airtight?

Do you have any other advice? Would any pictures help?

Thank you a lot for your help, it is greatly appreciated!

 

[Btyre2013]

you'll have to build a room within a room, with all floating ceilings, walls, floor, e.t.c, that's the only way to truly isolate it, and to do it well it costs a lot of money. You have to ask yourself, is it REALLY worth it? when that room isn't ideal to start with.

Do you own the property?

 

[BroKen_H]

The problem is: Building a soundproof ceiling will not isolate the ceiling. The vibration through the walls that are not isolated will still send bone jarring bass up through the ceiling via the connections to the walls...you would need to isolate the ceiling from all the walls (probably as expensive as floating a room in a room considering construction issues...)

 

[janwesterm]

Thanks for your replies.

I am aware, that I will need to build a completely free standing room.

My idea so far was as attached (quick drawing in MS paint, still working on Sketchup model)

Will these layers of plasterboard on the inside of the new structure be sufficient and create an air cavity with the existing structure or would you consider adding plasterboard on top and the outsides of this construction?


Edit: Yes, the space is owned, not rented.

 

[BroKen_H]

Okay. First you start with a floating floor. Some kind of vibration isolation system. Then you build your walls with this kind of structure...

Isolate the ceiling on top.
Use lots of green glue for everything. Use dense insulation materials.
Remember that when you insulate and isolate, you need some form of ventilation. That should face one of the walls that is not in question and probably be QRD'd or diffused in some way once the sound is out...

 

[janwesterm]

The wall you suggest is a staggered stud wall, right? How is this beneficial in my case, when I plan to construct the wall studs standing on the floating floor and the existing structure is concrete? I could also build a double stud wall, thats not an issue, as I have sufficient space.

If I understand correctly, your suggestion is to add inner and outer layers of plasterboard to my construction to create an air cavity and not consider the existing structure when talking about air cavities, due to its leaking nature?

Any specific advice on how to isolate the top ceiling? Is the new floating ceiling (if closed above and below with plasterboard and added insulation) not sufficient from your point of view?

Thanks for the advice with green glue and isolation material, I already planned on this.

Thanks again for all your help! It is greatly appreciated!

 

[BroKen_H]

I don't know how loud you are planning to practice. If you're going to be at the 80dB level you probably are wasting your time doing any of this, but if you are going to practice full on amplified music with real drums, you're going to push 115dB. You will need all the help you can get! Less dB is less.

Vibration is vibration. If the wall on the inside is connected to the wall on the outside via the stud, the sound is transferred through the stud directly. If those studs are staggered, there is no direct transfer. If all the studs are attached to the floor there is indirect transfer, but there will be indirect transfer whether you stagger the studs or use them to connect both walls together. You could alternatively use iso clips to hang your drywall or to float the studs off the floor. Less dB is less...

Not air cavity, but sound absorption. The idea was not to leave the wall empty, but to use some form of sound absorbing material between those walls. Yes the air gap on the outside of the walls will add to the absorption, and will greatly dissipate what sound comes through...again, less dB is less.

iso clips of all sorts are available. These folks are in the States, but if you check around, you should find one in the EU that will sell to you... Anyway, the point is, you can hang a ceiling floating on the studs, just like you'd float the floor.

Depending on how much you want to spend, you could make the inner room so quiet, you would need very little air gap outside (except where you want your vents...breathing is still a good option! ).

 

[BroKen_H]

BTW, I'm no expert at this stuff, but if you were to PM, say, JHBrandt or Ethan Winer, you might get some interesting feedback.

 

[mjbphotos]

Depending on how much you want to spend, you could make the inner room so quiet, you would need very little air gap outside (except where you want your vents...breathing is still a good option! ).

Except you need enough of a gap to hang that sheetrock on the outerwall!

 

[janwesterm]

Thanks for your replies!

I am planning to rehearse will a full rock band.

As for ventilation, I will need to install an Air conditioning, as summers in Greece are very hot. I will make the connection with the outside unit of the split system as long as possible and possibly S shaped.

I have started the Sketchup Model, at least for the existing structure I am done, and I have now just quickly put together a sketch of how I planned my structure to be, so maybe this helps to understand better.

As for the new structure, to understand the sketches better, I planned:
- Floating floor on wood studs, laying on isolation pads (possibly Sylomer, calculated to specific load).
- Fiberglass to fill the cavity under the floor
- 2 layers of flooring (not sure yet what material)
- New wall structure resting on new constructed floor, with 2 layers of plasterboard with green glue, fiberglass between studs
- Fiberglass on existing walls
- New ceiling resting on new wall studs, 2 layers of plasterboard with green glue as well

Would you still add an outside layer to the new structure that I planned and therefore not consider the existing one?

I also dont see the reason for using resiliant channels for this construction, as it should be already completely decoupled or am I missing something?