ceiling in my room within a room

bigerock · Post by **bigerock** » Wed Jun 16, 2004 6:23 am

short and sweet.

im building a sound "proof" drums practice room (read:quiet) in a CORNER of my garage. i think i understand many of the concepts here.

1) my floors are concrete subfloor, so no floating floor.

2) im probably going to employ a wall design like this one: (the one that reads 'STC 57')

<img src="http://johnlsayers.com/phpBB2/files/par ... 3.gif"><br>

3) how do i construct the ceiling?

if i just throw some 2x4s or 2x2s (for space reasons) on top of my walls, and cover both sides with drywall, that will negate all my hard work on the walls.

so, any advice?

giles117 · Post by **giles117** » Wed Jun 16, 2004 7:49 am

Check out the SAE site, pleanty of ceiling construction diagrams there for yah.

bryan Giles

knightfly · Post by **knightfly** » Wed Jun 16, 2004 3:35 pm

First of all, 2x2's won't support even ONE layer of drywall safely, but there can be other ways - can you post a drawing of your existing construction, or a digital pic showing the ceiling/frame detail? Please resize as necessary to keep pix/drawings down to 800 pixels or less in width... Steve

bigerock · Post by **bigerock** » Wed Jun 16, 2004 11:43 pm

i will post a picture tonight of my existing space. thanks for your input!

bigerock · Post by **bigerock** » Fri Jun 18, 2004 3:34 am

here's some various pictures of the corner of my garage. and a couple renders and a basic schematic. let me know what you think.

this is a drum practice room only. perhaps a future recording room.

obviously the junk will be cleaned out, but this is the corner of the room.

bigerock · Post by **bigerock** » Fri Jun 18, 2004 3:35 am

and here's a couple of renders...

bigerock · Post by **bigerock** » Fri Jun 18, 2004 3:38 am

and a basic schematic

knightfly · Post by **knightfly** » Fri Jun 18, 2004 8:50 am

Interesting drum kit; I LOVE that "tuned percussion"

(which, technically, I guess a piano really IS "tuned percussion"...)

Just funnin' witcha, when I grow up I wanna be a smart-ass

Seriously though, a few possible problem areas - don't get fooled into building a triple or quad-leaf system; part of your existing construction will act as part of your isolation system, whether you want it to or not.

If you could supplement your excellend drawings with some more details, we can get this figured out. Need things like ceiling height (acoustics are not 2-dimensional) measured from slab to ceiling panels, actual construction that's in place (what materials, how thick, how attached, insulation type (if known) existing wall construction (2x6 stud, 5/8 sheet rock, studs on 24" centers, what's on the other side, stuff like that)

The good news is, you may only need about 2/3 the materials you've shown.

Oh, also need to know if that slab continues into the house, or if the house is a perimeter foundation with wood framed floors, or??

Nearest neigbor, which side, cranky or rabid Metallica fan...

Electrical locations, how it will be included in construction (this can make or break isolation)

Ventilation (do you wanna play drums, or just die of heat stroke?)

Never said this was gonna be easy, just interesting...

Steve

bigerock · Post by **bigerock** » Fri Jun 18, 2004 10:33 am

knightfly wrote:... don't get fooled into building a triple or quad-leaf system; ...

what's a tripple or quad-leaf system?

haha - yeah the drawing program only had a piano. so i used it. i figured it's roughly the space of drumset.

... as far as the other stuff you asked for...

1) the ceiling measures 8' 6" from slab to (popcorn) ceiling

2) i dont know about the existing walls except that there's the metal garage door on one wall, 2 exterior walls with wood studs (2x6s i believe) and insulation, and one wall (the wall with the door that leads to the house) is an interior wall with a concrete base (elevates the rest of the house) and 2x4 wood studs with insulation.

the ceiling consists of 2x6 wood studs with drywall and basic insulation. all studs seem to be placed about 18" apart.

oh, and the exterior walls are plastered with stucco.

it seems to be 5/8 sheetrock throughout.

3) this is a south florida home (read: hot and humid 24/7)

4) electricity can be supplied from an exisiting outlet in the ceiling (i can have an electrican tap into that) and run somehow to the room.

5) i plan on using a window box air conditioning unit hung in an upper corner of the room, and just placed inside the room - not used the way a tradional window ac unit would be used. i read you could do this to cool the air that exists in the room, as long as you open the door every once in a while to get some fresh air in there.

6) the house is a total wood frame house, with stucco on the outside.

7) the floors are all concrete slab, some of which is carpted, some tiled, and one room has wood floors.

8 ) on the other side of the interior facing wall there is a hallway, and a mud room.

9) my nearest neighbor is about 15' away and that's their garage. meaning my garage is near their garage, so there should be some buffer zone. they have young kids and we are on good terms with all our neighbors. they all would be cool with a little noise now and then. it's a very young family, young kids-centric neighborhood. however, i want to make it so that i could practice drums at 2 am and have no one in my own house really hear anything. STC in the 50s or 60s?

THANKS SO MUCH FOR YOUR HELP!!!!

cadesignr · Post by **cadesignr** » Fri Jun 18, 2004 12:53 pm

Seriously though, a few possible problem areas - don't get fooled into building a triple or quad-leaf system; part of your existing construction will act as part of your isolation system, whether you want it to or not.

Hello Steve. I have a question and a picture of what your suggesting, I THINK

First the question. In regards to a triple, or quadruple LEAF system, I assume you are including the existing garage wall as part of a triple or quad leaf system, when combined with the new double wall, correct?
IF so, if the double wall, within the garage, constructed as the wall he chooses, that would imply that the double WALL system has an STC 57 rating, correct? What I would like to know, is HOW does another 2 leaf wall(the existing garage wall) LOWER the STC rating of the double wall? Since the EXISTING wall adds MORE mass, and the sound has already been attenuated by the double wall, how would sound INCREASE in level as it travels to the interior of the house through the existing wall, as it has already been attenuated by the double wall, no? Seems like a contridiction in logic, although I know sound is NOT logical

Ha! I know you've explained it and I have read many other statements regarding triple and quadruple leafs, this seems counter intuitive.

But just to go with the flow, here is my interpretation of what you are suggesting. Although, as per your suggestion on another thread of cutting holes in the existing sheetrock on the garage side, I suggested simply removing it, in those areas adjacent to the new construction. Is this correct?

fitZ[/quote]

bigerock · Post by **bigerock** » Sat Jun 19, 2004 12:08 am

im wondering if a new thread should be spawned on this subject. maybe from something about ceilings to garage practice rooms?

knightfly?

z60611 · Post by **z60611** » Sat Jun 19, 2004 12:33 am

Knightfly

First of all, 2x2's won't support even ONE layer of drywall safely

How about a 2x4 top plate and bottom plate, with staggared 2x4's rotated 90 degrees to the usual way (i.e. flat side to the gypsum). AcoustiBlok does it's Rivermore tests like this.

So, basically I'm asking is your comment about the downward vertical strength, or the twisting strength of the stud.

z60611 · Post by **z60611** » Sat Jun 19, 2004 12:44 am

cadesignr

At first glance of your drawing I thought that you had put gypsum on both sides of the new inner wall (which would be bad), but on second glance I see that the white lines are gypsum and the red lines are wood, so you got it.

What I would like to know, is HOW does another 2 leaf wall(the existing garage wall) LOWER the STC rating of the double wall?

Actually it raises the STC, but it lowers the TL for low frequencies.
STC is sort of an average over many frequencies, mostly about those involved in voice. So a high STC wall is better at stopping female yelling than a low STC wall.
Walls stop next to no sound at their resonance frequency. The closer two layers of gypsum are together, the higher the resonance frequency.
So, for example, a 100mm (3.5") wall space between leafs might resonate at 60hz, whereas a 200mm (8") wall space between leafs might resonate at 40hz, and a 1" wall space between leafs might resonate at 114hz, and a 1/2" wall space between leafs might resonate at 159hz.
3.5" spacing corresponds to a simple 2x4 stud wall.
8" spacing corresonds to a double stud wall.
1" wall spacing corresponds to a quadruple leaf wall with a 1" gap between the inner two leafs (if one could build such a thing)
1/2" wall spacing corresponds to RC between gypsum layers {gypsum, RC, gypsum, wood studs, gypsum}
You probably have a lot of music that has 100hz to 200hz sound in it, so using RC this way or a quadruple leaf wall would be bad. Whereas there's less music that has 40hz to 50hz sound in it.

Certainly in new construction, it's cheaper and more effective to put any gypsum you have on the outsides of the wall system.
Unfortunately, for this garage, a layer of gyspum should be destroyed (removed) to increase the LF TL, and that will cost money (waste of material, demolition time).

bigerock · Post by **bigerock** » Sat Jun 19, 2004 1:06 am

...

you guys are infinitely more knowledgeable than i am on this subject.

to sorta start over, does anyone have any suggestions as to how i should construct my garage practice room?

it seems that using the existing walls might be the way to go, based on current discussions.

...

z60611 · Post by **z60611** » Sat Jun 19, 2004 1:39 am

bigerock

I see from your drawing that you have a piano. The lowest note on a piano is A0 at 27.5 hz. What is the lowest note that you play in 90% of your music?

A piano can be played at 90-92 decibels, but do you have any idea how loud you normally play at in db(c). If not, then you might want to buy a Radio Shack sound level meter and find out. The louder you play, the larger the sound isolation.

What's outside the room (upstairs, outside, downstairs) and how important is it that the noise of the piano not be heard?

Are you doing recording in the room? And if so, how big is the piano.

Are you in fact using the room for piano, or drums?

Do you know what the ceiling is made of? (e.g. 2x8 studs on 16" centers with OSB and carpet above). What is the floor made of?

We can use these two pieces of information to recommend walls. (i.e. the cheapest and yet most likely satisfactory wall system)

For example we can take the db(c) numbers, and unweight them into a list of SPLs by frequency. Then we can look up wall systems using ir761. Then subtract the SPL from the ir761 numbers. Then subtract the Fletch-Munson Robinson-Dadson curves to find out how loud it will be outside the room. We'll also throw in insul48SA.exe estimates too.