Band rehearsal studio build (edited)

[antknee75]

Just getting started on my build. I am planning to build a space to use primarily as a band practice space, but will do some demo recording. I am not focused on building a mixing room or recording studio space. Primary function is live music and it will need maximum sound reduction. However, I am have some limiting factors to deal with and would appreciate any suggestions.

1. I am converting a 12' x 20' detached one car garage. (11' 6" x 19' 4" from stud face to stud face) So, I would like to avoid losing interior space by building a room within a room. I would like to achieve the highest sound reduction possible with the thinnest wall possible.

2. My neighboring house is quite close. I havent actually measured, but it is about 15 feet. It is a rent property, and tenants cycle through about once a year. I make it a point to tell them I'm a musician and make noise, but so far tenants there have been very accommodating and cool about it. But in the end, if I am annoying someone living there, they can move.

3. The garage has two windows, on the opposite side from my neighbor, that I'd like to be able to use for natural light, but temporarily cover while playing. I know there are coverings for this, but windows will work against me here.

4. The exterior walls consist of 1/2 inch plywood sheathing with tar paper wrap and hardyboard siding. Roof is typical plywood deck with asphalt shingles.

I have already gutted the building, and am in the process of vaulting the ceiling, cathedral style, to open up the space. The ceiling would be quite low, otherwise. There will be no joists and no attic space. The ceiling will consist of 2x6 rafters and an LVL beam when framing is complete. The finished dimensions will be 11' 6" x 10' 11" x 7' 8" with a 12' 2" peak in the ceiling.

I plan to use a ductless split AC/heat system.

So, I am just beginning my planning and research. I know that these conditions are far from ideal. Can I even accomplish a usable practice room under these conditions? I have researched various wall construction techniques and leaf systems, so I know a room within a room is the best for my needs. However, the room will be small enough as is. I really dont want to lose a foot or so of floor space from each side to accommodate greater wall width.

I greatly appreciate any input and suggestions.

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[antknee75]

Vaulted ceiling progress. The ridge beam is installed.

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[Paulus87]

If you feel that you do not require the room to be isolated (sound proofed) then no need to add anything other than your acoustic treatment.

However, if you feel that you would like the room to be isolated then as you've already discovered a room within a room is the best way to achieve this with the existing building that you have.

Is building an outer decoupled shell around the outside of your existing building an option? So the existing building would then become your inner leaf.

Paul

[antknee75]

I do want to reduce the sound level outside the building as much possible while minimizing the overall depth of the wall.

I am considering using the existing 2 leaf wall, with standard 2x4 framing. (I am not framing two decoupled walls with large gap.) On the interior, I am going to layer MLV > clips/hat channel > 3/4" OSB > green glue > 5/8" drywall. I might decide to just go with two layers of drywall, but I like the idea of having OSB behind the drywall so I can hang panels, guitars, shelves, etc.

The exterior wall is very weak. It is actually 3/8" plywood (not 1/2" as I thought) with hardy board siding. I am looking for ways to increase mass on the exterior wall from the inside, like attaching drywall panels to the plywood, between the studs. However, there are lots of nails protruding through the plywood that attach the siding. So, I don't know how to handle that problem yet. I'm open to suggestions!

[Paulus87]

I do want to reduce the sound level outside the building as much possible while minimizing the overall depth of the wall.

I am considering using the existing 2 leaf wall, with standard 2x4 framing. (I am not framing two decoupled walls with large gap.) On the interior, I am going to layer MLV > clips/hat channel > 3/4" OSB > green glue > 5/8" drywall. I might decide to just go with two layers of drywall, but I like the idea of having OSB behind the drywall so I can hang panels, guitars, shelves, etc.

The exterior wall is very weak. It is actually 3/8" plywood (not 1/2" as I thought) with hardy board siding. I am looking for ways to increase mass on the exterior wall from the inside, like attaching drywall panels to the plywood, between the studs. However, there are lots of nails protruding through the plywood that attach the siding. So, I don't know how to handle that problem yet. I'm open to suggestions!

Firstly, you mention that you have an existing two leaf wall; How? Is it because you have a layer of siding and a layer of ply? That is not a two leaf wall, that is a single leaf with 2 layers.

Secondly, regarding your plan; you'll only get a small amount of transmission loss by using resilient channel and clips, especially since the existing timbers are only 2x4s. This is because 1. the air cavity between the two leaves will be minimal (only 3.5" minus the thickness of the layers of mass you're going to apply between the studs, so more like ~2.5") and 2. the outer layers of sheathing/cladding will not be fully decoupled from the inner new layers of osb/drywall.

Thirdly, I wouldn't use MLV in that way. In order for MLV to function it needs be hung limp, as soon as it is constrained (like it would be if you were to fix a load of resilient channel with screws onto it) it's effectiveness decreases significantly. I would just use an extra layer of drywall so you would have OSB with a double layer of drywall. However, I know they also have weight limits, so you need to check the RC can handle that load.

Then you have the problem maintaining the same mass as the walls on the ceiling. That's going to be a massive challenge since 1. you have a cathedral ceiling, so the angle will make it slightly more difficult and 2. I am not sure that your current rafters are strong enough to take the weight of your proposed assembly - you'll have to get that checked out by someone qualified to make that call.

My point is, even after all this hard work and money it may not be enough to significantly reduce the sound levels blasting out annoying your neighbours. It will be better of course, but your low frequencies will pretty much pass straight through.

If you still decide to go this route then there's numerous ways to take care of the protruding nails; hammer them down flat onto the OSB, or apply a layer of styrofoam/polystyrene with a thickness that equals the length of the protruding nails before you apply the new layers of mass, or simply take the siding off and replace it/re-apply it later.

Another potential problem I see for you is you either need to ventilate your roof (while still maintaining air tightness in your double leaf assembly) or convert it to a hot roof (warm roof). If you decide to ventilate it then you'll need to build a roof on top of your existing roof with soffit vents and a ridge vent. This new roof will be a bit like a "third leaf" but not really since it will have big holes in it. If you go the hot roof route then you'll need the correct R value rigid insulation on the outside of your roof deck which will eliminate the need to build a new roof, and it does not need to be ventilated.

In conclusion, are you sure you cannot build a whole new outer shell around your existing building? It might be easier in the long run if maximum sound isolation is your goal.

Paul

[antknee75]

Firstly, you mention that you have an existing two leaf wall; How? Is it because you have a layer of siding and a layer of ply? That is not a two leaf wall, that is a single leaf with 2 layers.l

My mistake. I was referring to my original wall before I tore off the drywall. So, you are correct. As of right now, I have only the outer leaf, consisting of plywood and siding.

Secondly, regarding your plan; you'll only get a small amount of transmission loss by using resilient channel and clips, especially since the existing timbers are only 2x4s. This is because 1. the air cavity between the two leaves will be minimal (only 3.5" minus the thickness of the layers of mass you're going to apply between the studs, so more like ~2.5") and 2. the outer layers of sheathing/cladding will not be fully decoupled from the inner new layers of osb/drywall.

This is the kind of info I need. I was debating whether to use channel and clips and wondering if it would be worth the cost for the result. I see lots of varying information in my online research.

Thirdly, I wouldn't use MLV in that way. In order for MLV to function it needs be hung limp, as soon as it is constrained (like it would be if you were to fix a load of resilient channel with screws onto it) it's effectiveness decreases significantly. I would just use an extra layer of drywall so you would have OSB with a double layer of drywall. However, I know they also have weight limits, so you need to check the RC can handle that load.

Every example of an MLV installation I have found shows it stapled/tacked/nailed to the studs. Are you saying it should be hung limp, like curtains?

Then you have the problem maintaining the same mass as the walls on the ceiling. That's going to be a massive challenge since 1. you have a cathedral ceiling, so the angle will make it slightly more difficult and 2. I am not sure that your current rafters are strong enough to take the weight of your proposed assembly - you'll have to get that checked out by someone qualified to make that call.

The ceiling will have wider rafters installed to handle the weight. However, weight was reason I was planning to use only one layer of drywall over the OSB. I have a structural engineer that I am consulting on the framing work. So we are safe there.

Adding to the exterior of the building isn't an option. That would require extending the foundation or pouring a new footer to build on, which would bring up all kinds of time consuming and expensive issues with planning and permits. I can do what I want on the interior, but exterior work gets complicated.

Thank you for the input, Paul!

[antknee75]

I'm still digging around for what I should use to add some mass to my exterior wall. I am concerned about how thin it is. I'm considering just adding a layer of drywall between the studs, but the exterior plywood sheathing on the building is so thin, and I don't want to penetrate through to the outside with screws. I'm also considering MLV for this purpose, but it's so expensive that I don't want to do that unless the results are worth the expense.

I know this is unconventional, but has anyone tried to do this before?

Here's a quick sketch of my wall section.

WALL DETAIL.jpg

[Paulus87]

I'm still digging around for what I should use to add some mass to my exterior wall. I am concerned about how thin it is. I'm considering just adding a layer of drywall between the studs, but the exterior plywood sheathing on the building is so thin, and I don't want to penetrate through to the outside with screws. I'm also considering MLV for this purpose, but it's so expensive that I don't want to do that unless the results are worth the expense.

I know this is unconventional, but has anyone tried to do this before?

Here's a quick sketch of my wall section.

WALL DETAIL.jpg

You could use cement board. It has twice the surface density of drywall and is moisture resistant. You could even take your siding off and use the cement board as your siding, which you can paint, so long as you get the weather resistant type.

Adding drywall between the studs would be totally possible, you wouldn’t screw it into the plywood you would use wooden cleats to hold it in place, and the cleats are screwed into the studs. So you wouldn’t risk them penetrating the siding. It is however a tedious process.

Regarding your question, Are you asking if anyone has used resilient channel before?

Paul

[antknee75]

You could use cement board. It has twice the surface density of drywall and is moisture resistant. You could even take your siding off and use the cement board as your siding, which you can paint, so long as you get the weather resistant type.

Adding drywall between the studs would be totally possible, you wouldn’t screw it into the plywood you would use wooden cleats to hold it in place, and the cleats are screwed into the studs. So you wouldn’t risk them penetrating the siding. It is however a tedious process.

I'll look into the cement board, but it seems to me that cutting that to size for each space would be messy.

They drywall with wood cleats screwed to the studs sounds like it might be the way to go here.

Regarding your question, Are you asking if anyone has used resilient channel before? Paul

No. I'm just wondering if anyone has attempted to add mass to the exterior wall from the inside, by installing material between the studs.

Thanks, Paul!

[Paulus87]

You could use cement board. It has twice the surface density of drywall and is moisture resistant. You could even take your siding off and use the cement board as your siding, which you can paint, so long as you get the weather resistant type.

Adding drywall between the studs would be totally possible, you wouldn’t screw it into the plywood you would use wooden cleats to hold it in place, and the cleats are screwed into the studs. So you wouldn’t risk them penetrating the siding. It is however a tedious process.

I'll look into the cement board, but it seems to me that cutting that to size for each space would be messy.

They drywall with wood cleats screwed to the studs sounds like it might be the way to go here.

Regarding your question, Are you asking if anyone has used resilient channel before? Paul

No. I'm just wondering if anyone has attempted to add mass to the exterior wall from the inside, by installing material between the studs.

Thanks, Paul!

Oh, yes it’s done all the time, it’s even used by pro designers such as rod Gervais and Wes Lachot, I expect there are hundreds of studios where this has been done.

It’s known as “beefing up”.

You can do it with as many layers as you like too, just bear in mind that it will decrease your cavity size between your inner and outer leaves, especially if you’re planning on using the one set of framing with resilient channel.

Here in the uk we have a product which is especially well suited to beef ups, it’s called gypsum plank board. It’s 19mm thick, and 600mm wide but still 2400 long = 2’x8’ which means it’ll fit better between your studs if they’re 24” OC with less cutting. Its also about 16kg/m2 which is about double the mass of 1/2” standard drywall. And it’s really cheap!

Paul

[antknee75]

Oh, yes it’s done all the time, it’s even used by pro designers such as rod Gervais and Wes Lachot, I expect there are hundreds of studios where this has been done.

It’s known as “beefing up”.

You can do it with as many layers as you like too, just bear in mind that it will decrease your cavity size between your inner and outer leaves, especially if you’re planning on using the one set of framing with resilient channel.

Here in the uk we have a product which is especially well suited to beef ups, it’s called gypsum plank board. It’s 19mm thick, and 600mm wide but still 2400 long = 2’x8’ which means it’ll fit better between your studs if they’re 24” OC with less cutting. Its also about 16kg/m2 which is about double the mass of 1/2” standard drywall. And it’s really cheap!

Paul

I am planning on the one set of framing with resilient channel, so I don't want to take too much from the wall cavity.

Just did some quick searching, and I don't think that product is commonly available here in the US. There are some products called gypsum, but it looks like they are basically just drywall. It looks like drywall will be the convenient option.