Basement Drum Room In Townhouse

[merpmerp]

Greg,

Right now we're only worried about the acoustics with the low volume cymbals as well as the electronic set pad noise, correct?

I don't think we're talking about full blown acoustics because I think we determined there would be too much involved there.

Do we really need to worry about the four boxes in that case? What if I went straight down from the vent with an extension into the inner leaf with some type of baffle system, then out of the inner leaf into the HVAC room with one or two systems? I'm not worried about the sound in my own house just the neighbors.

Thank you

[Gregwor]

Are there any examples that you know of that I can look at? If I put up wood, doesn't that turn it into a three leaf system?

If you read pretty much any threads on this forum, they are inside out builds. So hopefully you can find enough pictures to clarify any questions you may have.

It wouldn't be a 3 leaf system because your outer leaf only has one layer of mass, then your inner leaf (which is inside out) has one layer of mass. That's it. Nothing more.

OK, what about the outer leaf? What am I doing with that? That has no insulation or anything in it right now. Am I just putting insulation in it, putting insulation and drywall, doing nothing, or something completely different?

You make it so that it is air tight. Imagine filling it with water. Is there anywhere the water would leak out? If so, seal it. There should be NO spot on your entire outer leaf that has less mass than your minimum amount required. This is why you box in existing mechanical stuff. This will also require you to extend your walls all the way to the foundation and seal it all up.

Then, between this outer leaf and your inner leaf, you fill it completely with insulation. For your inner leaf drywall that is facing the foundation, you will need vapour barrier fixed to the drywall before you stand the wall up.

OK, I also have room, and more of it on the opposite side in the HVAC room. The A/C went is currently in the middle of the room in the ceiling. If the first box is on the outer leaf in the sump pump room, how am I getting it from the A/C vent to that box? Am I using additional duct work? I would assume so, I just want to make sure you're not referring to moving that vent.

You will have to re-work the duct work for your room. I presume there is no way you're going to be able to run a designated HVAC system for the room. It sounds like you're planning on using your existing home unit. Now, the only problems with this idea are:
- Say your jamming and sweating your butt off but the rest of your home is comfortable. The thermostat isn't going to see a problem and it won't turn on your A/C. So what do you do then?
- Since your room is air tight, there is only fresh air brought in when your air handler blower is running. The only way you're going to get fresh air while you jam is to run your blower all the time.
- Can your air handler unit fan handle the extra static pressure drop introduced by your silencer boxes and extra duct work?

The other option would be to install a ductless mini split then install duct work to remove stale air and give you fresh air. These would be small ducts as they only need to swap out 30% of your calculated CFM for 6 air changes per hour. That means smaller silencer boxes too. BUT, you will need to cut holes on the side of your house to dump stale air and bring in fresh air. This is also quite inefficient energy wise. So, to fix that problem, you could use an HRV. Typically you can away with using the HRV built in fan to move the air for you as well!

This is an expensive fix though.

It does need to stay and I would not want to remove it but where it is right now, it would not interfere with the inner leaf ceiling. Couldn't I just leaf it as is if that is the case?

I don't fully understand your question.

Right now we're only worried about the acoustics with the low volume cymbals as well as the electronic set pad noise, correct?

Sure. You have to decide that, not me.

I don't think we're talking about full blown acoustics because I think we determined there would be too much involved there.

So you're not doing a room in a room? I have a lot on my mind and might not be following your thread entirely at this point! I hope we've provided you with enough information to make an informed decision about the type of construction you need to build to perform as you require.

Do we really need to worry about the four boxes in that case? What if I went straight down from the vent with an extension into the inner leaf with some type of baffle system, then out of the inner leaf into the HVAC room with one or two systems?

Okay so I'll clarify how many boxes you need:
Each leaf needs a box. If you don't do a room in a room, you need 2 boxes (one supply one return). If you do a room in a room, you need 4.

I'm not worried about the sound in my own house just the neighbors.

This goes hand in hand. You either have isolation or you don't. You can't control who gets to hear it and who doesn't. The sound either stays in/out of your room for everyone or no one.

Greg

[merpmerp]

OK Greg,

You've given me plenty of information. I just have one last question because I'm not sure if the last answer was addressing the ceiling or the walls.

Regarding the current ceiling that I have now, which, is currently just the joists with nothing else.

What, if doing the room within the room, would I be doing with the outer leaf ceiling?

Thank you

[Soundman2020]

What, if doing the room within the room, would I be doing with the outer leaf ceiling?

Depending on how much isolation you need, and what is on top of those joists, there are several options. But basically the plan is the same; you want to end up with just two "leaves" of mass between you and the outside world. The inner-leaf ceiling sits on top of the inner-leaf walls, and it does not touch the outer leaf at all.

- Stuart -

[Gregwor]

Depending on how much isolation you need, and what is on top of those joists, there are several options. But basically the plan is the same; you want to end up with just two "leaves" of mass between you and the outside world. The inner-leaf ceiling sits on top of the inner-leaf walls, and it does not touch the outer leaf at all.

This all depends on if you are doing a fully decoupled room in a room build or a iso clips and hat construction. You have to decide and tell us exactly how much isolation you need. Are you building for a full acoustic kit like you initially mentioned or the electric kit/pads usage?

Presuming there is 3/4" sub floor above your existing joists, you will most likely have to beef up that mass in either scenario. This is because Mass Law is in charge no matter what.

So, in either case, beef up the existing sub floor mass. For any mechanical stuff, build boxes around it and fill those boxes with insulation around the mechanical. For all of the other joist spaces, you need to also fill those with insulation.

From there, you will either build your inside out ceiling like Stuart mentioned. Or, you'll install your iso clips and hat channel.

Before you do any of that though, you need to design your HVAC and build it accordingly. You might have silencer boxes or duct work running in those joists.

Greg

[merpmerp]

Greg, Stuart,

Thanks for that information. One thing I'm not understanding regarding the isolation clips and hat channel:

The first layer of drywall gets screwed into the hat channel.

Does the second layer of drywall get screwed into the hat channel as well?

Thank you

[Soundman2020]

Does the second layer of drywall get screwed into the hat channel as well?

Yes, definitely! And with longer screws...

- Stuart -

[merpmerp]

beef up the existing sub floor mass

Does this mean adding drywall between the joists? I know Stuart said originally said that would be tough to do. If that is the case would I use glue for that? Would it stay?

Yes, definitely! And with longer screws...

Great, thank you!

[Soundman2020]

Does this mean adding drywall between the joists?

If you need the extra mass on that leaf, then there's three places you can put it: 1) Add it from below, in between the joists. 2) Add it on top, with an extra layer of mass over the existing sub-floor. 3) Replace the existing sub-floor as well, with a higher density material. You can do any one of those three, or any combination. As long as the TOTAL mass in the end is enough to get the isolation you need.


- Stuart -

[merpmerp]

OK, thank you. The only way I would be able to do it would be to put it between the joists.

In the Gervais book is is up with 1 x 3 blocks on the joists. Is that the best way to go about it? My joists are more like the truss with a lot of empty space in between.

Thank you

[Gregwor]

In the Gervais book is is up with 1 x 3 blocks on the joists. Is that the best way to go about it? My joists are more like the truss with a lot of empty space in between.

You can use rectangular blocks for dimensional lumber type joists or for my I joists, I made custom cleats.

image1.jpeg

image3.jpeg

Seal all along the joists and any joints in your sub floor before anything. After a day or so go and touch up anywhere you may have missed. Then, cut your drywall and put Green Glue Compound on the back side of the drywall. Lift them into place and install your cleats. Seal around the drywall but don't seal around the cleats themselves. Let that caulk cure. Then in a day or so, go and inspect it to make sure you didn't miss any spots. Touch up those spots. Then, remove your cleats and caulk where they were. Put a few thick dabs of caulk on the part of the cleat that pushes up against the drywall. Reinstall the cleat in a different spot than you initially had it.

Done.

Greg

[merpmerp]

Thanks for the pictures, that helps a lot.

Am I putting green glue between the drywall and the subfloor?

If I planned on using two sheets of drywall between the joists would I just put green glue between the two?

When you say seal up everything, is that with caulk or acoustical sealant?

Regarding the moving the cleats and then putting them in another location, does that mean they're staying up there permanently?

Thank you

[Gregwor]

Am I putting green glue between the drywall and the subfloor?

Yes. Put it on the drywall before you lift the drywall up against the subfloor.

If I planned on using two sheets of drywall between the joists would I just put green glue between the two?

g
I'm pretty sure GG says there is a slight improvement if you put GG on each layer, but it's a small improvement. The greatest improvement is realized in the first layer.

When you say seal up everything, is that with caulk or acoustical sealant?

It's the same thing. Caulk, sealant, acoustic sealant. I recommend not using the Green Glue brand sealant. I personally found that white Dynaflex 230 was very easy to use, cheap and doesn't show signs of shrinkage.

Regarding the moving the cleats and then putting them in another location, does that mean they're staying up there permanently?

Yes. For safety reasons, it's good to have them up there. The caulk holds it up there good during the cleat moves, but I wouldn't trust it to be strong and never let go.

Greg

[merpmerp]

Does it matter if the drywall that is going between the joists is touching the joists?

Also, my contractor had a question, and I told him you guys said contractors will like to take shortcuts so I said I would ask on here.

Regarding the cleats, he wanted to know if we could have one long one going the entire length on both sides of the drywall between the joists, and, if not, why not?

Thank you

[Gregwor]

Does it matter if the drywall that is going between the joists is touching the joists?

The whole idea of using Green Glue Compound for beefing up your subfloor is to have the drywall sort of "float" on the compound. That is why we hold up the drywall with cleats instead of screwing the drywall to the subfloor. So, regarding the joists, you should leave ~1/8" or maybe more space on each side of the drywall to fill that void with caulk/sealant. This caulk/sealant will remain flexible (similar to the Green Glue Compound).

Regarding the cleats, he wanted to know if we could have one long one going the entire length on both sides of the drywall between the joists, and, if not, why not?

Sure you can, but that's a waste of money and it also eats into your gap. I made mine 3" long.

Greg