Piano room over slab

Aaberg · Post by **Aaberg** » Wed Aug 04, 2004 2:39 am

OK. Here's one for ya. I'm building a studio to record my piano, because I'm tired of waiting until 2 in the morning to record in the old church it currently inhabits. The slab under the piano room is 20 inches thick over sand and gravel. It's isolated from the rest of the studio. There is radiant heat in the slab. From my research (and admittedly there's always more I can find and learn...) I think I'm OK not to raise the floor and just use a layer of polyethylene barrier plus a sixteenth inch of foam, plus sub floor, plus engineered wood flooring (seems to be best for radiant heat).
Any comments on that?\
Now...the manufacturer of the wood flooring says that there's no problem with putting a piano on the stuff. The piano won't be moved much, if at all. I'm also wondering if I should float the floor under the piano just to be on the safe side, or is that overkill, considering the thickness of the slab and its isolation?
Thanks.

Innovations · Post by **Innovations** » Wed Aug 04, 2004 3:27 am

TWENTY INCHES! What was it, a bank vault?

Since the floor is radiant heat, I would go with not floating the floor because as you said it is so thick (!) and isolated from the rest of the structire.

I always thought that a going-out of business bank's vault would make the ultimate iso room.

Aaberg · Post by **Aaberg** » Wed Aug 04, 2004 3:35 am

Naw...the concrete just had to come up to the level of a house. We do have a bank vault in our office...and yes, that's where we store the "tapes". A piano won't fit in there, however. Might be good for fiddle and accordion. (OK now...no jokes.)

Innovations · Post by **Innovations** » Wed Aug 04, 2004 6:16 am

Aaberg wrote:Naw...the concrete just had to come up to the level of a house.

So they did it by pouring twenty inches of solid concrete? That's just SO absurd.

Aaberg · Post by **Aaberg** » Wed Aug 04, 2004 8:35 am

Got another way? the slab is 20 inches at the edge, so the concrete goes all the way to the ground. Kind of like your legs, you dig? Unless you're floating on air. The middle of the slab has an elevated rise of sand and gravel, so in the middle, the slab is less thick. This slab ties together 2 houses, kind of an architectural deal, gnome sane?

Innovations · Post by **Innovations** » Thu Aug 05, 2004 2:19 pm

Aaberg wrote:Got another way? the slab is 20 inches at the edge, so the concrete goes all the way to the ground. Kind of like your legs, you dig? Unless you're floating on air. The middle of the slab has an elevated rise of sand and gravel, so in the middle, the slab is less thick. This slab ties together 2 houses, kind of an architectural deal, gnome sane?

Of course, that is a thickened edge slab-on-grade foundation, but that is WAY different than a 20 inch slab, which is what he said.

Aaberg · Post by **Aaberg** » Sat Aug 07, 2004 2:04 am

Sorry about the lack of clarity...any suggestions from anyone else re: my original question?

knightfly · Post by **knightfly** » Sat Aug 07, 2004 4:02 am

"The slab under the piano room is 20 inches thick over sand and gravel. It's isolated from the rest of the studio." -

Meaning that there is no hard connection between this slab and the rest of your construction? If so, what about wall framing, ceiling/roof framing, etc - any hard contact there between areas?

Innovations pretty much covered it as far as floated floors over radiant heat - not a good plan. If your slab is already isolated, you could just do either RC/drywall over studs and under ceiling joists, or full double wall construction - maybe a sketch or pic of what's there would help us help you... Steve

Aaberg · Post by **Aaberg** » Sat Aug 07, 2004 4:49 am

Thanks, Steve. I'm pretty much set with what I have to work with for walls. Will send picture...I'm pretty sure this is the only recording studio in the world with this construction, but who knows?
My main concern now is with the floor of the room. In fact, this leads me to a thought I had this morning. Most of these posts don't stick to one topic, but relate to one PROJECT. That's very good for the builder of the one PROJECT, but it makes it very convoluted to try and look up info on one TOPIC, i.e. Floors. I can see the advantages of both ways, but I'm trying to just post something different for each topic in my building. Would you prefer that I just post once and get all answers on that "Subject" heading? Is that clear?
Thanks.

knightfly · Post by **knightfly** » Sat Aug 07, 2004 6:35 pm

Yeah, so far it seems to me that the "project" approach works better for the "projectee" - for other members, if you're looking for specific topics the search engine can help. I'm working on a real FAQ type section which will probably not happen for several months, since it's summer and I only have 4 major and about 15 minor projects I need to start/finish before bad weather sets in again.

It was suggested recently that I gather the "stickies" into a single heading so they wouldn't take up so much room on the first page - I'd been thinking about doing that, although I'm still not sure it's a good idea - already, new members come in asking questions to which the answers are already available, so I'm not sure hiding the "stickies" would be a good thing.

Maybe I'll start a poll on ways of improving accessibility of the info that's already here - the amount of time I've already put into this would have bought me a new Yamaha DM-2000 if I'd spent the time at my job on extra projects... Steve

Aaberg · Post by **Aaberg** » Sun Aug 08, 2004 8:06 am

Steve,
I can't begin to tell you how much this forum and your input has helped me. Very solid stuff...any difficulty finding stuff is minor compared to the service we get. Just wondered if you had a preference for how we submit messages, and even thought that if you decide on a "best" way, you might use that as an introduction to the site.
Sincerely,
Phil

knightfly · Post by **knightfly** » Tue Aug 10, 2004 3:16 pm

Cool - I've been toying with the idea of an online "form" - one with all the blanks people typically forget to fill in when first posting - I think that would save a lot of "back and forth" - not sure how to make it generic enough to apply to the majority of members' questions, though... Steve

Aaberg · Post by **Aaberg** » Wed Aug 11, 2004 3:00 am

Yeah, I guess you could list the most-posted topics (insulation, floors, wall, gypsum, )...it'd take some thought, huh? Thanks for the great work...we really appreciate it.
I'm still searching for someone who's insulated a curved wall. Found a farmer in Kansas who's built an office out of a grain bin and his builder has some ideas, but not to the sound-insulating specs we're hoping to get.
I can figure out how to get the insulated wall/air space/insulated wall right, but can't figure out how to seal the 703 on the second wall. Will continue this on a Subject called "curved walls/ceilings".

knightfly · Post by **knightfly** » Thu Aug 12, 2004 5:58 am

703 doesn't need to be sealed at all, just inserted snugly between studs.

For outer wall mass, if this bin is steel, what about a 1" layer of stucco on the inside, then steel studs (25 gauge, and don't try to support the ceiling on these - they need to be light, because you can't get RC to go around a curve and still work for decoupling), fill with insulation (2-3 PCF ideally), then go to a drywall supply house (home depot doesn't count) and ask for 1/4" drywall (yes, it does exist) and do 4-5 layers of that over your steel studs?

IF you support the two ends of the stuff for a couple days (without supporting the middle) you can pre-bow it to close to the arc you need for a circular wall - then, (carefully, the stuff is fairly delicate) screw each successive layer to the studs, starting each course offset vertically and horizontally from the last - for every other course, you'll want half-width sheets - cut these first, and THEN pre-bow them.

This is used in some houses for curved partitions - for sound, you just need more than the normal two layers of 1/4" to get the extra mass.

Check locally for Myron Furguson's book, "DRYWALL" (catch title, hun?) Or order it from Amazon. I found mine at Home Depot, yours may or may not carry it. The book shows a lot of drywall pix, including this laminating curved wall stuff... Steve

Aaberg · Post by **Aaberg** » Fri Aug 13, 2004 12:37 pm

Steve,
Thanks a million for the research. I spent all day Tuesday reading all the posts in the forum...most time I've spent on a computer since the last piece I orchestrated. My eyes hurt! But there's an incredible amount of great info here.
So, the upshot is that we decided to stay away from curves and completely float the interior walls! We did it! Finished the framing today.
No parallel sufaces, no 90 degree angles. It's some pretty complex geometry, but looks right and is really striking. Will send pictures and may even get around to a drawing. Every wall is floating on a half inch of EPDM that we got dirt cheap from a local roofer, then cut with small metal shears into pieces that fit under 2X6. It took 8 layers to do, but sure a lot cheaper than buying the pucks. None of the walls touch the bin. The peak is 18 feet high and the lowest line is a bit under 16. Didn't lose much floor space at all because of the way we cut into the bin with the SIPs.
The bin is covered with an inch of urethane foam for weather seal and rigidity, then one and a half inches of cellulose insulation. Supposedly gives 51 STC, but I doubt it. There is a minimum of 8 inches of air space between the insulated bin and the dry wall, sometimes as much as 12, and actually 3 feet between the roof of the bin and the interior roof.
I'm going to put R38 fiberglass between the interior roof and bin roof because it's easy to do and seems right.
My question is, what should I use to insulate the air space in the walls and how should I apply it?
Thanks for all the help.
Phil

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