rehearsal room in row house - combining wall elements?

Hi all: YIKES, 1,100 words. Sorry. I have questions about combining different elements of studio construction. I’d like to build a one-room rehearsal studio in the basement of my row house in Washington DC. My music can be loud, and is only a weekend hobby. I’d love to hear your thoughts on a good design. First, my criteria: (1) low budget - US$2,500 in materials max; I will do all the work myself. (2) substantial isolation, but it need not be total as I will restrict my playing to the weekend daytimes. Perhaps knock off 50-80dB from a 110dB punk band. (3) it must resemble a “normal” room (to appease the girlfriend/co-owner) so no slat-type wall treatments, etc. Besides this need not have studio-quality acoustics. I have attached a sketchup model, as best I can do with the program (sans wall treatments). It includes layers with my ideas for the design. The raw basement: It’s a typical DC row house that looks a bit like this except there are steps from the front yard down to the basement door: http://www.dcpreservation.org/endangere ... 0Perry.JPG The basement is accessible from the first floor kitchen and from the street via a door located underneath the front porch. It has a poured concrete floor. The foundation walls, shared with the neighbors, are double-wall brick with an air gap, totaling I think 9-10 inches wide: about every ninth row, the bricks are set perpendicular to the row, to lock the two brick walls together. (This width is an estimate – could be thicker.) EDIT: THE WALLS ARE ACTUALLY 15-16 INCHES. MUCH BETTER! :D A hefty 8-inch i-beam is set in the foundation walls, which continue up two more stories; the i-beam also rests on three 13” square foundation pillars spaced 112” apart, along the length of the basement. Resting on the i-beam, and set into the shared brick walls, are joists for the first floor. You can see all this in the sketchup file. The approximate height between the concrete floor and the joists is about 7’ 9” (2057mm), although I set it for 8’ in the sketchup file by accident. The i-beam sits 8” below that, and there is also a fair amount of radiator pipes, a gas line, and water supply pipes – all of which I think must be enclosed with soffits. In my model I have shown basically where the pipes are. My choice for the location of the studio is the cooler (north) end of the house. Unfortunately, that is where the chimney base, furnace and water heater (both gas) reside, so a utility room with sufficient clearance and air circulation (for the gas to combust properly) must be built. A very heavy, well-sealed door to the outside leads to the street, and a flimsy window as well. I plan on stuffing some layers of heavy drywall into the window-well whenever music is to be played. The proposed design: The room would be semi-triangular, 18ft wide by 16ft 3in. long, and I guess 7ft 4in. high with a suspended ceiling. Lemme try this math: 5486mm W x 4953mm L x 2237mm H. I plan to build a suspended ceiling using resilient clips, hat channel, and two layers of 5/8” drywall with GG. I also plan to build wood staggered stud walls, with layers of 5/8” drywall. (I guess using 2x6 sole plates and headers, and 2x4 studs.) To keep costs down, I am thinking two layers on the drum-side of the wall, and one layer on the other. Mold-resistant 5/8” drywall costs $14+ a sheet. Which reminds me: moisture was once an occasional problem in this house, as one neighbor’s house is in such poor condition that water occasionally seeped into our basement. (He lives there, year round, without electricity, gas or oil heat, etc. I stopped feeling sorry for him months ago; but I won’t comment further because I feel a rant coming on.) There are some parts of the walls which are slightly damaged and may have to be parged someday. I have repaired his porch roof and his chimney, to good effect – it’s cheaper and more neighborly than suing him. As his house worsens, I need to monitor if any further moisture is entering our house. For about 8 months the moisture has not returned, but for my own reassurance about my house, I want to keep the floor and shared walls exposed so that moisture (if it returns) will not build up, damage the foundation, and cause mold growth. So let me add one more criterion: (4) All brick walls must *somehow* remain mostly exposed to circulating air. In my design I have included a double-door from the “studio” room into the rest of the basement. These doors enclose a closet which must house an existing electrical panel box built into the ceiling joists. (Perhaps a portable air conditioner can be placed there someday, also, but for now ventilation will occur by opening the window and door.) I really don’t want to have to move that electrical panel! The questions are these: (Q#1) what do you think of the shape/size of the room? It totals 182 sq ft., and 1335 cu. ft. (Q#2) what do you think of my idea of enclosing the room with varying elements: heavy brick walls, a suspended ceiling, a concrete floor (with a cheap Persian rug), and staggered-stud walls? (please keep in mind that my house and my neighbors’ house have wood joists seated several inches into the brick walls, so I think I will have to seal/soffit those breaches into the wall for better isolation.) Another way of posing the question: can I achieve substantial isolation from my neighbors and the rest of the house even though I am not building a floating floor, and even though I am leaving the brick walls exposed? Can this design reduce a 110 dB live band practice in the basement to an acceptable 30-60 dB on the first floor? Can it reduce the band practice down to 30-50 dB for my neighbors? (Q#3) would a small drum riser on neoprene pads pose any benefits? (Q#4) is the brick wall I have described a two-leaf, or one-leaf design, or does it matter given its substantial mass? (Oh, and the Gervais book is in the mail.) EDIT: PLEASE SEE CORRECTED PICTURES BELOW.

Hi Blandman, and welcome!

YIKES, 1,100 words. Sorry.

More words is better! (As long as they are useful words) So don't be sorry. You did a good job describing everything that needs to be described, by the looks of it.

Perhaps knock off 50-80dB from a 110dB punk band.

That's a rather large range! 80 dB of isolation is (literally) one thousand times more than 50 dB. It needs to block 1000 times more energy. 80 dB isolation is MAJOR isolation. Even most studios don't aim for such high figures. 80 dB of TL would make a manic drummer into total silence. To give you an idea of what you have in mind, 30 dB is roughly as loud as what you would hear standing in the middle of the desert on a windless night.... 50 db is doable, 80 db is impossible on your budget.

The foundation walls, shared with the neighbors, are double-wall brick with an air gap, totaling I think 9-10 inches wide: about every ninth row, the bricks are set perpendicular to the row, to lock the two brick walls together.

OK, so that kind of wall will basically act as a single-leaf, with a fair amount of mass. Good. I can't open your SketchUp as it is done in V8 and I'm still on V7, unfortunately, so I'll base my comments on your text...

and the joists is about 7’ 9” (2057mm), although I set it for 8’ in the sketchup file by accident. The i-beam sits 8” below that

so you have 7'1" of usable headroom? Not much to work with. This is just going to be a rehearsal room, right? Not for recording?

Which reminds me: moisture was once an occasional problem in this house, as one neighbor’s house is in such poor condition that water occasionally seeped into our basement.

:shock: OK, so which of the walls on your picture is the one that adjoins his place?

and a flimsy window as well. I plan on stuffing some layers of heavy drywall into the window-well whenever music is to be played.

I don't see the window on your picture: where is it? And how are you going to get to that window to put in the plug and take it out again, where your inner-leaf is going to be in the way?

I also plan to build wood staggered stud walls, with layers of 5/8” drywall. (I guess using 2x6 sole plates and headers, and 2x4 studs.)

It sounds like you are going to build 3-leaf walls in some places, with that plan! Not good. Only two-leaf. The inner-leaf walls that run parallel to the existing brick walls can have drywall on only ONE side of the studs, not both sides. So those only need to be 2x4 frames, not staggered stud. And if you are going with that plan, then you might as well continue the same for the other walls, rather than try to join those to staggered-stud walls for the others.

I plan to build a suspended ceiling using resilient clips, hat channel, and two layers of 5/8” drywall with GG.

Getting the kind of extreme isolation that you are talking about using RSIC clips is unlikely. On the other hand, you don't have much headroom to be able to do a proper MSM ceiling supported on the walls, which would be the way to maximize isolation. Tough call...

To keep costs down, I am thinking two layers on the drum-side of the wall, and one layer on the other.

Bad idea. Keep it all at two sheets, if you want isolation. The room has to be built to the exact same level all around. if you do two leaves on everything, except for one small patch of just a single square foot that is only one layer, then your entire isolation is limited to only one layer. The entire room is a system, and it only isolates as well as the weakest link. You can't do some walls better than others: the worst wall is what you will get.

All brick walls must *somehow* remain mostly exposed to circulating air.

That's REALLY hard to do! The entire operating principle of an MSM wall is that the air in the cavity is trapped between two hermetically sealed leaves. As soon as you cut a hole into that system to allow air to circulate, you compromise your isolation. The only reasonable solution I can think of is to make your air gap so large that you can actually walk in it, to inspect the walls occasionally. Can you afford to lose that much floor space?

In my design I have included a double-door from the “studio” room into the rest of the basement.

I see your double doors, but the aren't accomplishing much since there are multiple flanking paths between the two leaves! For example, both of the leaves that those doors are in, are joined by walls. So you are not decoupling.

(Perhaps a portable air conditioner can be placed there someday, also, but for now ventilation will occur by opening the window and door.)

Not a good plan for HVAC! You plan to have people in this room, right? People have this unusual habit called "breathing". They have to do it several times per minute, or they stop being people... Your room will consist of two absolutely airtight hermetic seals, one inside another, and will be surrounded by very thick layers of insulation. Put a few people in there, and it will become unbearably hot in a very short time, not to mention the lack of breathable air... In other words, you need to re-think your HVAC plan: it is seriously deficient. Your band will pass out in there, before you get the first song fully rehearsed. You need to get fresh air in and stale air out, through proper ducts with in-line silencers and fans. You also need to cool and de-humidify the air in there, with some kind of air conditioner that is correctly sized for the dimensions of the room, and for the number of people / amount of equipment that will be in there. HVAC is a big deal.

(Q#1) what do you think of the shape/size of the room? It totals 182 sq ft., and 1335 cu. ft.

Good enough volume, but the ceiling will be very low, around 6'10" or less. Can you live with that?

Another way of posing the question: can I achieve substantial isolation from my neighbors and the rest of the house

Yes, but not 80 dB

even though I am not building a floating floor,

You most likely don't need to float your floor, and you certainly don't have the budget or the space to do it, so you are stuck with whatever you can get by not floating it.

and even though I am leaving the brick walls exposed?

:?: I don't see any exposed brick walls on your diagram! I see an inner-leaf all the way around. If there is any break in that inner leaf, then you do not have any isolation. The inner leaf must be a completely airtight envelope, just like the outer leaf.

Can this design reduce a 110 dB live band practice in the basement to an acceptable 30-60 dB on the first floor?

With an exposed brick wall and no MSM? No way. maybe 70 db, with luck. With a proper MSM system, it should be possible to get your 60 dB, but no way will you ever get down to 30 dB with that budget. Add two zeros on the end, and you are in the ballpark.

Can it reduce the band practice down to 30-50 dB for my neighbors?

same answers as above. 30 db is very, very quite. "Midnight in the desert" quite. a very soft whisper six feet from year ear is already ten times louder than 30 dB. To be honest, I think that is an unreasonable goal. You are also starting from an reasonable premise at the other end: An average drum kit all by itself can put out 115 dB, played hard. Add in the rest of the band and you could be pushing 118. That is very much louder than the 110 you are starting from. getting from 118 to 30 is a massive 88 db of TL. That is unreasonable. Most folks here consider themselves lucky to get 70 dB of isolation for their studios, and 60 is probably closer to the norm, for a good build. Drums are the hardest instruments of all to isolate. They are also the loudest, and have the most low frequency energy. They also put impact noise into the floor. All of that adds up to it being very, very tough to isolated a drum kit down to 30 dB.

(Q#3) would a small drum riser on neoprene pads pose any benefits?

yes. If it is designed and built well, it will seriously reduce the impact noise into the building structure. That is very good. But you don't really have enough room height to be able to build a decent drum riser.

(Q#4) is the brick wall I have described a two-leaf, or one-leaf design, or does it matter given its substantial mass?

The brick wall is one leaf, since the air gap is bridged in numerous places with those "sideways" bricks that directly couple the two sides. And yes, it has mass, but nowhere near enough to give you 88 dB of isolation. More like 50-something, with luck, and assuming that the mass is consistent throughout, and the wall is well sealed all over on both sides.

(Oh, and the Gervais book is in the mail.)

Good move! You should probably also get yourself MHoA. Summarizing: You need to either rethink your design goals, or rethink your plan, or rethink your budget. Or all three. Getting down to 30 dB is an unrealistic goal, no matter what. You can't even get close without build a fully-enclosed, fully decoupled MSM room. - Stuart -

Thanks for the detailed thoughts! This is really helpful.

Quote: Perhaps knock off 50-80dB from a 110dB punk band.

That's a rather large range!

Yeah I see that now. I think my neighbors can live with a 50-70dB level. So I will revise my goals a little. But I will clarify below my plan, because it wasn't clear from my original post.

Quote: and the joists is about 7’ 9” (2057mm), although I set it for 8’ in the sketchup file by accident. The i-beam sits 8” below that

so you have 7'1" of usable headroom? Not much to work with. This is just going to be a rehearsal room, right? Not for recording?

I will not be using the room for any serious recording, just for playing/practicing. The joists sit above the I-beam, and I have been planning to soffit around the ibeam (and have the suspended ceiling butt up against the soffit). So headroom directly under the I-beam will be as low as you say (or lower even), but elsewhere in the room it should be a little better. Anyway, that's the plan. By the way, I measured the basement walls a little more carefully. It turns out the basement walls are 15-16 inches thick, not 9-10 inches as I said in my original post. (I had measured the wall depth on my first floor, not thinking that the basement walls would be thicker than at the first floor, duh.) The window to the outside is right to the left of the doorway. I forgot to put it in! Also, the area that suffered some small water damage is the area around that window, the electrical panel in the corner, and the doorway itself. I should also clarify something very important: several of the walls in my present plan will be exposed brick. I can see now that this wasn't clear from my diagrams, because I used more or less the same color for the brick walls as for the drywall! I have attached a revised sketchup file (version 6) and new pictures so that you can see what I mean better. Here is a top view:

Quote: (Perhaps a portable air conditioner can be placed there someday, also, but for now ventilation will occur by opening the window and door.)

Not a good plan for HVAC! You plan to have people in this room, right? People have this unusual habit called "breathing". They have to do it several times per minute, or they stop being people... Your room will consist of two absolutely airtight hermetic seals, one inside another, and will be surrounded by very thick layers of insulation. Put a few people in there, and it will become unbearably hot in a very short time, not to mention the lack of breathable air... In other words, you need to re-think your HVAC plan: it is seriously deficient. Your band will pass out in there, before you get the first song fully rehearsed. You need to get fresh air in and stale air out, through proper ducts with in-line silencers and fans. You also need to cool and de-humidify the air in there, with some kind of air conditioner that is correctly sized for the dimensions of the room, and for the number of people / amount of equipment that will be in there.

Understood. What I meant was that the "closet" could serve as a place to store an in-line silencer type system, with fans, etc.

On HVAC: After doing some research, I am leaning towards an energy recovery ventilator, probably a fantech SE704N (for 1,200 sq ft, the smallest they have) that I will run throughout the entire basement, including the little studio. Question: Has anyone had any experience with ERVs in the Mid-Atlantic area? On isolation: I still am planning on going with the suspended ceiling (using 2 sheets of 5/8" drywall), plus a staggered-stud wall with two sheets of drywall on one side, and one sheet on the other. Still wondering if that is an appropriate solution. Question: Is it important to have equal mass on both sides of a staggered stud wall? On using two different kinds of walls: And, I am still thinking of leaving the brick walls uncovered, and enclosing one end of the basement with that staggered-stud wall. Any thoughts on combining these two different kinds of walls?

why staggered stud versus separate walls? space? cost? maybe consider a single steel stud wall with 2x 5/8" on each side since you're not supporting the ceiling on the walls. if you're doing this with unequal layers, i put the 2x on the outside and 1x on the inside to get some bass absorption out of the "thinner" inner wall.

Thanks for your comments. Yeah the reason for one staggered stud wall rather than two separate walls is because space is at a premium in my basement. Steel stud would seem to be preferable to wood I guess, since moisture is always a risk in any basement. But why do you not suggest staggered steel stud? Is that a waste of effort for my goals?

i think the single steel wall will have as much isolation as the staggered wood stud wall due to the decoupling effect from the steel. one trick on the staggered stud is to trim a small corner off each stud and rip a gap down the top and bottom plates to effectively create a very narrow double wall. blocking has to be done with the block being vertical in order to clear the opposing stud.

That's interesting that a single-stud (non-staggered) steel wall will have as much isolation as staggered-stud wood wall. I wonder why more people don't use steel studs, especially because they are so much more forgiving in terms of construction than wood. Truth is, I was considering using steel studs all along, but I had actually figured wood would be better for isolation, which is why I had made that my plan in my OP. I'm still curious to hear people's thoughts about the shape of the room. I know it is unusual and is pretty much required because I need a separate utility room in that area of the basement. And my priority here is isolation, not acoustic treatment. But will this shape (and the I-beam soffit, for that matter) present major acoustic problems, given my expected height of about 6'7" or so? I don't want to spend the time and money to build a room with good isolation, and create a room that is physically tiring or uncomfortable to play in!

tradeoffs, the weaker steel is not good for construction where you are supporting ceilings for example. also the lack of stiffness has consequences for MSM response of the wall but in general (a bad choice perhaps for terms) if single steel wall will tend to be better than a single wood wall. the good folks at NRC have a number of documents which show how specific construction tactics yield different results.