A few building questions for my specific situation

[n1ck]

Hey guys –

I’ve been lurking for a while and learning a lot!

I live in NJ and am looking to ‘soundproof’ a room in my basement. Essentially, I’m a drummer and want to be able to play without disturbing the neighbors.

The room is 13x13 with a linoleum floor. I would imagine there’s concrete beneath it. The house is kinda weird with various levels of basement-ness, so it’s hard to say. But it is the lowest point in the house, so I guess it’d have to be concrete, right?

If it is, could floating the floors (especially if not done 100% correctly) stand to make the overall isolation worse, or just merely be a waste of money? I’ve read a lot on here about the silliness of floating floors on concrete.

In terms of walls, like I said, I’m in an existing room of the house, so does that mean two leaves are already accounted for – those being the interior walls of the existing room (prior to any buildout) and whatever drywall is on the other side of each of those?

If a two-leaf structure is the way to go, wouldn’t that mean I’m already doomed?

In other words, I have an existing room. Each wall has two leafs: the inner drywall layer, and the outer drywall layer. When I add even one more layer of drywall to the new ‘room within a room,’ I’m at three leaves, right?

One solution would be to just add additional layers of drywall to the existing inner wall, and not build a room within a room, but then there’d be no decoupling, right? Isn’t decoupling the essence of this whole thing?

Can someone help me?

To summarize:

1. There’s a linoleum floor in the room I’m trying to build out. There may be concrete beneath it. I’m not sure. Will floating the floors make isolation worse if done at all incorrectly, or just be a waste of money? Honestly, I’d rather float them just to be safe, and because I’m not sure of exactly what’s underneath.

2. What approach should I use in dealing with the walls – add layers to existing ones, or build a room within a room? If I go RWAR, I don’t think tearing down the existing inner layer of drywall (to remove one leaf from the equation) will be a possibility.

Thank you all so much!

[Soundman2020]

Hi Nick, and Welcome!

Yeah, this whole "float or not" and "2-leaf / 3-leaf" things can be more than just a bit confusing! It's not very intuitive at all.

Essentially, I’m a drummer and want to be able to play without disturbing the neighbors.

First order of business: Try to put numbers to that. In other words, get a sound level meter, find out how loud you play, typically, and find out how loud that is for the neighbors: see if you can get them to let a friend into their homes with the meter, while you are playing, to measure how loud they are hearing it. If you explain why you want to do this, you might find that they'll be OK with you measuring inside. Then also measure the ambient levels when you are NOT playing. And finally get a copy of your local noise regulations to find out what your legal obligations are. Based on all that, you should be able to come up with a number, in decibels, that roughly identifies how much isolation you have right now, and how much extra you need. That number is the key to the whole deal of isolating your drums.

The room is 13x13

Ooops! That's square! You might want to consider ways of making it not-so-square as part of your whole isolation thing. Being square or not doesn't matter much for the isolation issue, but it does matter for you and how your room will sound inside. With two dimensions being identical, you will very probably have large modal resonance issues. Worth looking into...

with a linoleum floor. I would imagine there’s concrete beneath it. The house is kinda weird with various levels of basement-ness, so it’s hard to say. But it is the lowest point in the house, so I guess it’d have to be concrete, right?

Probably, but not necessarily. Is there any way you can find out for sure? If you tap on the floor with something like a shoe or a small stone, does it sound hard and solid? Or does it sound hollow? Is there any place you can get a look under that floor, to see what it is made of, or what is under it? Many houses have "crawl spaces" under floors, for access to water pipes, electrical system, HVAC ducts and suchlike. If you look around, you might find the access panel to that crawl space.

If it is, could floating the floors (especially if not done 100% correctly) stand to make the overall isolation worse, or just merely be a waste of money?

Very likely it would make it worse, and even if it didn't change it all, in both cases it would still be a waste of money. Doing it right is not so easy, requires lots of mass, and is expensive.

I’ve read a lot on here about the silliness of floating floors on concrete.

If you need high levels of isolation, and your concrete slab is not resting directly on the ground ("slab on grade"), then it might be necessary to float the floor under unusual circumstances. But in most cases, it isn't necessary.

In terms of walls, like I said, I’m in an existing room of the house, so does that mean two leaves are already accounted for – those being the interior walls of the existing room (prior to any buildout) and whatever drywall is on the other side of each of those?

Right. You have coupled 2-leaf walls. "coupled" because the drywall on both sides is mechanically connected through the studs, but "2-leaf" because the empty gaps between the studs act like that. So it's a combination: not as bad as one leaf, but not as good as true decoupled 2-leaf.

If a two-leaf structure is the way to go, wouldn’t that mean I’m already doomed?

Not doomed! It is still possible to build a 3-leaf wall that isolates well: it is just harder, more expensive, and takes up more space. It can be done, and you can compensate for the 3-leaf effect, but in most cases it is easier to just get rid of one of the pesky leaves. So don't throw in the towel: it is still possible.

In other words, I have an existing room. Each wall has two leafs: the inner drywall layer, and the outer drywall layer. When I add even one more layer of drywall to the new ‘room within a room,’ I’m at three leaves, right?

Yup. But if you were to take the drywall off your side of the wall before building the inner-leaf, then you'd be down to 2-leaves again... And if you were to use the same pieces of drywall that you take off to "beef up" between the studs, then you would be in a really good situation.

Another option is to take off the drywall, put resilient channel across the studs, then put the drywall back again.

Yet another (but very similar) option is to take off the drywall, put RSIC clips on the studs, and put hat channel on the clips, then put the drywall back again.

Those last two options turn your coupled 2-leaf into a decoupled 2-leaf, which greatly increases the isolation.

One solution would be to just add additional layers of drywall to the existing inner wall, and not build a room within a room, but then there’d be no decoupling, right? Isn’t decoupling the essence of this whole thing?

Adding mass does increase isolation but not by much. You have to double the mass to get an increase of 6 dB. And double it again (4 times the original) to get anther 6 dB. Not very hopeful.

Decoupling is the key to getting good isolation with relatively low mass.

2. What approach should I use in dealing with the walls – add layers to existing ones, or build a room within a room? If I go RWAR, I don’t think tearing down the existing inner layer of drywall (to remove one leaf from the equation) will be a possibility.

If you can't take apart the existing walls for whatever reason, but you can add layers and you can build new walls, then your best option would be to add a couple of layers of 5/8" drywall to the existing wall, then build your new wall (third leaf) with a good sized air gap between it and the existing wall, and also have a couple of layers of drywall on that, perhaps even with Green Glue in between. A wall like that can get you upwards of 50 dB of isolation, if done well.

You can do the ceiling in the same manner. Then you also need to think about the door(s) window(s), ventilation, and electrical aspects. Those need to be handled carefully as well, to ensure that the room isolates well.

But the basic answer here is: Yes, you can still get decent isolation with a 3-leaf system if you have no other options, provided that it is done properly. It will be a bit harder, cost more, and take up more space, but it can be done. 3-leaf is not a death sentence!!!

- Stuart -

[n1ck]

Thank you so much, Stuart! Really appreciate it!

[n1ck]

Hey guys -

I have a potentially stupid question.

So normally, when finishing a basement, you’d obviously attach both the bottom and top plates of the new wall frame to the existing structure: the bottom plate to the concrete floor, and the top plate to the joists above you.

Since the RWAR scenario requires decoupling from the existing structure and only allows drilling of the bottom plates to the existing floor, how are the top plates of the new frame secured? What keeps them from falling over?

[Soundman2020]

Since the RWAR scenario requires decoupling from the existing structure and only allows drilling of the bottom plates to the existing floor, how are the top plates of the new frame secured? What keeps them from falling over?

When you build a house, what keeps THOSE walls from falling over? There's no hooks hanging from the sky to attach them to... But your house stands up prety well all by itself: So what keeps it there, and stops the walls from falling over?

It's the exact same thing that stops your inner-room from falling over. The same principle that keeps your house walls from falling over, also keeps your inner leaf studio walls from falling over: structure.

First, since each wall meets two other walls at right angles (one at each end), it is prevented from falling either inwards or outwards by those other walls. But it could still fall "sideways" in sheer if you loaded it heavily and unevenly ("falling" in the sense of collapsing within the same plane, with the top sliding along its own length while the bottom stays put). That's why walls need bracing in their own plane. There are several ways of doing that, but the easiest for studios is to do it the same way most house walls are done these days: by nailing panels of OSB or plywood to the wall as the first layer, then adding a layer of drywall on top if necessary. OSB and plywood are both pretty strong in sheer (drywall is not), and they provide more than enough strength for a typical wall. (Of course, if you don't use OSB or plywood for the first layer, then you are stuck with more traditional methods, such as cross-bracing diagonally with 2x4s.)

But that still doesn't keep the middle section of the wall top from flopping about. Even though the ends of the wall and the sole plate are all firmly attached so far, and the wall won't fail in sheer due to the sheathing, the top plate is still unsupported in the middle, and can sway and wobble... until you put your ceiling framing on top, which prevents that! Your ceiling joists are large hefty bits of wood, usually even large than the wall studs, and they tie the tops of the walls together so that they cannot flop around. The ceiling holds the wall tops rigidly in place. And since you also put OSB or plywood on the ceiling framing as the first layer, just like you did with the walls, you also provide strength in the ceiling plane, so it cannot warp or twist.

Thus, each wall is supported on all four edges by the other walls, the floor and the ceiling. And the ceiling is supported at all four edges by the walls. It all interlocks together, in exactly the same way as the shell of your house. If you build it right, it will be every bit as rigid as your house structure itself, and should in fact be much more rigid, due to the way studios are built. Those walls wont fall over any more than your house walls might fall over.


- Stuart -

[n1ck]

Thanks again, Stuart, for patiently answering my questions!

Would you be able to point me to any threads that talk about surface-mount electric and how that all works with regard to the main power feed, etc.? Couldn't find too much using the search tool.

Also, if poss., where might I find specific info on the 'V' part of 'HVAC,' as I once saw you put it?

I've also seen you talk a bit about using acoustic caulk before getting certain walls into place. Is that right? Have I gotten something wrong there?

Thanks so much!

[n1ck]

Howdy -

Just wanted to follow up and see if someone could help me out.

Please disregard my last post. I think I've solved some of those issues and / or can now rephrase a few things.

Is it possible for someone to provide an overview of the components that make up, like, the simplest ventilation system possible? Is it essentially: one duct going in the room to give fresh air, one duct going out to remove stale air, and then a fan in each of the two ducts that helps move the air in the right direction?

Is there a centralized 'hub' of some sort that controls fan activity or what?

For the duct providing the room with fresh air, does that air have to come from outside (as in the outside world / outside the house,) or can it simply come from 'outside the room'?

What about the duct that removes the stale air - where does all that have to get dumped to?

Finally, in principle, in the scenario I outlined above, assuming you have those two ducts (one for providing new air, one for removing the old,) how many baffle boxes would you need for the entire system, and where does 'best practices' support that they go?

I'm trying to isolate one single basement room from the rest of the house and the outside world.

Thank you all so much. I'm learning a ton here. I just have millions of super-specific questions!

[Soundman2020]

Is it possible for someone to provide an overview of the components that make up, like, the simplest ventilation system possible? Is it essentially: one duct going in the room to give fresh air, one duct going out to remove stale air, and then a fan in each of the two ducts that helps move the air in the right direction?

That's basically it, except that you also need silencer boxes at the point where the duct goes through the wall. Since the duct is basically just a huge hole in the wall, and obviously you cannot have ANY holes in your wall, you need the silencer box to compensate for that. It allows the air to go through while stopping the sound from going through. And like all parts of your HVAC system, the dimensions and materials need to be calculated....

About the fans: In reality you only need one fan, which can go in either the supply duct, pushing air into the room, or in the return duct, sucking air out of the room. Since the room is sealed air-tight except for the ducts, that single fan is enough to keep the air moving through both ducts. And here too, the characteristics of the fan have to be calculated according to the room and the ducts: you need a fan that provides ZZZ cubic feet per minute of air flow into a duct with a section of YYY square inches, at a speed of XXX feet per minute, where the duct system has a total static pressure of WWW inches. ... Fun and games!

Is there a centralized 'hub' of some sort that controls fan activity or what?

You can have a variable speed fan if you want, in which case you need the speed controller located some place where you can get to it when needed, but where it won't be adjusted by accident. You might need that if you have sudden large changes in room occupancy. For example: you working alone in the control room is a very different load as compared to suddenly having the entire ten-man band crammed into the room to listen to their song.... the another sudden change when they all leave, and you are alone again. You'd want to be able to turn up the flow rate to compensate, then turn it down again. Or you could get it done automatically by installing a CO2 sensor in the room, and getting that to control the flow rate.

For the duct providing the room with fresh air, does that air have to come from outside (as in the outside world / outside the house,) or can it simply come from 'outside the room'?

Yes, it must come from the outside. HVAC regulations do not normally allow one room to exhaust into another room.

What about the duct that removes the stale air - where does all that have to get dumped to?

It goes outside again: For the same reason: one room cannot exhaust into another room. So you have to keep your intake and exhaust ducts away from each other too: you can't have them right next to each other on the outside wall, as the exhaust air would be sucked right back in through the intake duct.

Finally, in principle, in the scenario I outlined above, assuming you have those two ducts (one for providing new air, one for removing the old,) how many baffle boxes would you need for the entire system, and where does 'best practices' support that they go?

If you need a high level of sound isolation, then you generally need one silencer box on each leaf penetration: In other words, where your supply duct goes through the outer leaf there is a silencer box, and where it goes trough the inner leaf there is another silencer box. The only exception is if you can design the room such that the box can sit between the two leaves, in the air cavity. In that case, one single box can do both leaves at once, provided that you design it carefully.

I'm trying to isolate one single basement room from the rest of the house and the outside world.

Is there an existing HVAC system in the house already? If so, then you might be able to tie into that. It might be possible to draw your fresh air from the HVAC supply plenum, and exhaust it to the HVAC return plenum.


- Stuart -

[n1ck]

Hey all -

Long time no post. Hope you're all doin' well!

I originally posted a year or so ago about buying a house in NJ, but since then have moved to central Virginia.

I'll soon be buying a house here and, of course, am very excited to get my plans back on track (building an isolated drum room that basically just looks like a nice finished basement space.)

I wanted to ask a specific question that I couldn't find an answer to with searching the forum.

If I'm building in a basement that is already connected to HVAC and electrical (i.e., already has operational vents and outlets connected to the rest of the house,) but I want to sort of 'bypass' those in order to install my own studio-specific HVAC and electrical systems, what do I do to kind of 'void' those out in preparation for the build?

Obviously you wouldn't just build a new wall over a vent that's gonna be blowing air into it, or an electrical outlet that's still powered, right?

Sorry for my really elementary question.

[Soundman2020]

Good to see you again, Nick! I was wondering what had happened with your other place...

To get rid of existing HVAC: If it is just a small duct feeding off the main plenum further back, then you can probably just remove the duct entirely and seal off the hole that it leaves in the plenum. However, that might upset the balance of the rest of the system, so it's better to hire an HVAC guy to come take a look and tell you what to do.

On the other hand, if you are going to remove the existing HVAC lines, then what are your plans for replacing them? Your room absolutely certainly needs HVAC, without any doubt at all, so you'll need to be running new ducts to your new system anyway: why not just tap into the existing ducts? Would that not be easier and cheaper than installing a whole new system when there's already one there that has the capacity?

Electrical: Get an electrician to take out everything. The general rule for studio isolation is that you can allow just one single feed point into each room, and then distribute it internally from there with surface-mounted structured system. That single feed point also has to be done correctly, decoupling the conduit and sealing up all the air gaps.

- Stuart -

[n1ck]

Hey guys.

Hope you’re all well.

It’s been a minute since I’ve posted, but we recently moved into our new house and things have been crazy.

Now that we’re in, I’m getting really excited about building my basement ‘drum lair,’ and in the coming weeks will no-doubt be posting regularly as I start planning.

I did want to hopefully gain some insight now, however, about one particular issue.

So by way of background: my new basement (in Charlottesville, VA) has cinderblock walls, a concrete floor (currently overlaid with partial asbestos tile) and is buried about three-quarters underground. Around the top of the walls (the part sticking out of the earth) there a number of windows.

The windows currently have thin, crappy glass and don’t appear to be very well-sealed.

Last night, my wife stood outside the house as I was playing, and sure enough, it’s really loud.

Being that the walls are cinderblock, the floor is concrete, and the basement is mostly underground, I’m assuming that the windows are the main culprit. Is that pretty safe to say?

I’m obviously a ways away from building the drum-room of my dreams, but in the meanwhile, I’d like to be able to practice down there a little bit without totally bumming the neighbors out.

Since I’ll ultimately need to beef the windows up as part of my outer leaf anyway (I definitely want to keep them as windows,) would it make sense for me to just go ahead and replace those now?

If so, is that something your “average window guy” can handle? I know I’m supposed to use a really thick type of glass. Do most window contractors stock that? Are there details, in terms of sealing the things and whatever else, that I’ll need to make them aware of?

I’m fine if they’re “non-opening.” Is that something they can do?

And then there’s one other complicating factor that plays into all of this: the eventual ventilation system.

Looking ahead to when the room actually takes shape, I’ll obviously need to provide for fresh air and a/c. Right now, I’m planning on a mini-split plus supply / return vents for fresh air.

I’m thinking that because, while the house does have central a/c, and the air handler is conveniently located near the drum space, I somehow have it in my mind that the vents + mini-split scenario will be easier and cheaper. Please set me straight if I’m wrong!

Anyway, if in fact the mini-split + vents are the way to go, do I need to be thinking about using the existing window holes as “ports” out of the house to eventually run the air ducts? If so, it certainly wouldn’t make sense for me to shell out the dough for new windows now!

Guys, I’m really sorry for the long-winded post. I wish I could ask these questions in more discrete terms, but I’m quickly learning just how inextricably linked every decision I make is to every outcome in the room!

Thanks so much in advance for your help.

PS – shoot. I just remembered one other thing. The house has radon. It was recently mitigated by the previous owner (there’s now a big-ass pipe running through the entire place that sucks up air through the foundation,) but I’m wondering if having “non-opening” windows in the eventually-finished room will put me at greater risk for health issues. What do you think? Is it even possible to have both the inner and outer leaf windows open to the outside world when building a RWAR?

[n1ck]

Just a gentle bump. I know you're all busy and the world doesn't revolve around me.

What can I say. My enthusiasm is getting the best of me!

[n1ck]

Hey guys –

Maybe it’ll help if I streamline my questions a bit. I realize the issue I posed was pretty thorny.

Basically I’m wondering…

Since the exterior windows in my basement seem to currently be my weak point, and since I’ll need to replace them anyway before bringing the room-within-a-room thing to fruition, would having them replaced now make sense? I’m looking to temporarily mitigate noise to the outside world so I can practice a little. The real build-out will take time, but I obviously need to be playing some music in the meanwhile.

Can an average window company install fixed exterior windows of the kind and thickness that I need, or would it make more sense for me to try and build them myself?

Thinking of the eventual ventilation needs of my space, if running vents / fans / ducts for ventilation, do I need to set aside one of the windows as a “port” to the outside world (and thus, should I not replace it)?

Is running vents / fans likelier to be easier and cheaper than tapping in to the existing central a/c in my house? The air handler is actually right next to my space.

Based on my having radon (it’s been mitigated with a pipe that runs vertically through the house,) is it dangerous for me to have fixed windows?

Thanks so much!
Nick

[n1ck]

Dudes?

[n1ck]

Hey all -

Just bumping this topic to hopefully catch someone's eye. Could really use some advice on the stuff above.

Thanks!