Plans for Construction

[jatougas]

Okay... while I continue wrestling with my floorplan, I'm going to back burner it for a bit and let my right brain gnaw on it. In the meantime, Id like to get an idea of what I need to do construction wise.

Situation refresher : 20'x20'x8' garage, most interior walls already drywalled and painted. A waterheater in the corner, two windows on the North wall 3 ft in from each corner, and a cement slab floor.

Right now, the garage is mostly being used for storage, so my first step'll be to weed it out, for stuff I want to keep, and stuff I need to get rid of. A lot of the stuff I'm keeping will end up in the attic above the garage. Also, I'll get rid of the garage door and build in that wall, with construction to match what'll follow.

But before I put anything up there, I need to acoustically dampen that space. My house is stick built construction, with a *very* thick beam running North to South (I want to say 6"x12"), 2x8 inch joists, 16" on center. I'm planning on stuffing those joists with rockwool, then a layer of plywood on top, to use as 'flooring' for the stuff I'll be moving up there. Then I'd put up a layer of 5/8" drywall ceiling in the garage (after scraping off the pebbling coat from what's already there).

After emptying the garage, I'll tear down most of the interior drywall, and add a 2x2 runner strip, to turn the 2x4 to 2x6 (good idea to put a layer of rubber in between the two, or under the runner?). I'll use staggered stud construction for all of the perimeter walls, except for the closet where the water heater and circuit panel will be (which'll be staggered stud walls). These walls will be stuffed with rockwool. The windows will be doubled, hopefully in a way that'll let me open 'em still. Should these walls also have a layer of the inside out construction?

The interior walls will be staggered stud construction on 2x6. Should I have them separated from the slab by rubber?

I'm also undecided about either floating a hardwood floor on rubber hockey pucks, or gluing hardwood flooring directly to the slab.

Things that'll need to be professionally done: 4 new circuits added to circuit panel (separate power & light to control room, separate power & light to tracking rooms).

My stepfather and I'll be able to handle the wall (re)construction, and the airconditioning additions. The airconditioning unit in place can handle the added space, pretty sure the furnace can too.

I'm planning on recording mostly acoustic music, and limiting my recording of drums and loud guitars, with some video production work.

Thanks for reading through this (damn, I got a lot of work to do ), and please let me know what I'm missing.

Cheers -

John Tougas

[jatougas]

*hesitant poke* Anybody? C'mon, I *know* I've gotta be missin' somethin'...

[knightfly]

You might be missing something; "I'm planning on stuffing those joists with rockwool, then a layer of plywood on top, to use as 'flooring' for the stuff I'll be moving up there. Then I'd put up a layer of 5/8" drywall ceiling in the garage (after scraping off the pebbling coat from what's already there)"

Do you mean for the upper plywood and the lower existing drywall plus the second added layer, to be your two leaves of mass for a mass-air-mass envelope? Also, what is the span of your 2x8 joists between supports?

If you have room, fully separate frames will increase your STC by about 12 dB and your low frequency TL by about 6 dB, given the same materials on the wall and the same overall thickness; it would be even better than that if you use 2x4 stud frames separated by 1" for a total air gap of 8", filled with insulation; I know your space is tight, but if you're worried about neighbors it's something to consider, at least for the outside walls.

BTW, inside out construction is fine for saving framing materials, but if you put the wall in the same place you will cut your internal air/insulation gap nearly in half; this means worse isolation. In order to maintain the same isolation while using inside out walls, the wall frames need to be further apart by the width of the stud. The upside of this is, you still get good iso and have a place to hang your absortion panels.

Should these walls also have a layer of the inside out construction?

If you want to save on lumber for treatment, sure; just be careful not to get a third leaf going between two areas, or you'll lose LF TL.

The interior walls will be staggered stud construction on 2x6. Should I have them separated from the slab by rubber?

Doing this requires more calculations than I'm up for at this time - if it's done wrong, you can end up with a resonance that will WORSEN your isolation value. I'd say no, especially since you're talking about staggered stud framing instead of separate frames - see above.

"I'm also undecided about either floating a hardwood floor on rubber hockey pucks, or gluing hardwood flooring directly to the slab. "

If you intend to do drums in there, you should float at least the drum room; this isn't a simple calculation either - you want the mass-spring-mass of the drum floor to be at least an octave below audibility, or IOW below 10 hZ - getting this requires a LOT of mass, a good sized air gap, complete fill with rockwool between joists, preferably 1" thick EPDM pucks under the joists, and fairly stiff framing (closer than normal spacing helps) - with costs what they are these days, it's actually cheaper to do a floated concrete floor in some cases than to do a lighter, less effective one with plywood, particle board, etc -

My stepfather and I'll be able to handle the wall (re)construction, and the airconditioning additions. The airconditioning unit in place can handle the added space, pretty sure the furnace can too.

Things to watch on this - if possible, make your extension ducts from Superduct, and make them at least twice the cross-sectional area of your existing ducts - this halves the air speed for the same volume of air, and will cut air noise drastically. Do separate runs for both supply and return to and from each room in the studio, each starting at the source and going to only one room.

Make sure each duct turns at least 180 degrees from end to end, and look for more open grilles to cut grille noise. You do NOT want either heat or cold ducts dumping into the room near speakers, or between you and the speakers; these temperature shifts can give you really strange audio effects, none of which will amuse you for more than a few seconds...

BTW, the reading part was easy; it's the answering part that can get involved... Steve

[jatougas]

Do you mean for the upper plywood and the lower existing drywall plus the second added layer, to be your two leaves of mass for a mass-air-mass envelope?

From top to bottom : One layer of 'stuff' in the attic. One layer of 3/4" MDF screwed down, rockwool in the ceiling cavities, 2 layers of gypsum (1/2" & 5/8").

Also, what is the span of your 2x8 joists between supports?

10 feet from wall to support beam, both sides.

it would be even better than that if you use 2x4 stud frames separated by 1" for a total air gap of 8", filled with insulation; I know your space is tight, but if you're worried about neighbors it's something to consider, at least for the outside walls.

Hmm... I can probably afford losing a few inches of space to insure not pissing off the neighbors. They're good folks. It'll also help keep out that jackass in the rumble truck...

The interior walls will be staggered stud construction on 2x6. Should I have them separated from the slab by rubber?

Doing this requires more calculations than I'm up for at this time - if it's done wrong, you can end up with a resonance that will WORSEN your isolation value. I'd say no, especially since you're talking about staggered stud framing instead of separate frames - see above.

Well, that'd save me some trouble... What should I do about attaching the wall to the ceiling? Does the same construction for exterior wall/ceiling apply for interior walls to ceiling?


"I'm also undecided about either floating a hardwood floor on rubber hockey pucks, or gluing hardwood flooring directly to the slab. "

If you intend to do drums in there, you should float at least the drum room;

I'm planning on concentrating on acoustic music, but I'm sure some drums will come into play at some point in time... What if I did a floating floor, framed with 2x4s, 12" on center, stuffed with rockwool, 1 layer of 5/8" MDF, 1 layer of hardwood flooring or ceramic tile, floated with rubber, neoprene or epdm? I was talking about the project with my boss at work, and she offered me contact info for a company that made the rubber feet they used for constructing a basketball gym floor.

You know you have a good boss when she encourages your outside activities like that.

My stepfather and I'll be able to handle the wall (re)construction, and the airconditioning additions. The airconditioning unit in place can handle the added space, pretty sure the furnace can too.

Do separate runs for both supply and return to and from each room in the studio, each starting at the source and going to only one room.

Superduct. Separate runs. At least one 180 in the duct. Gotcha.

BTW, the reading part was easy; it's the answering part that can get involved...

*chuckle* I'm planning on starting construction in about three months, diety of choice willing... I've got a few other home redecorations to do in the meantime.

Thanks for your help and info, Steve.

[knightfly]

Gotta run for now, but need to clarify a couple of mis-communications along with new answers - I'll try to get to this later tonight... Steve

[jatougas]

Gotta run for now, but need to clarify a couple of mis-communications along with new answers - I'll try to get to this later tonight... Steve

Take your time, I've got nothing *but* time.

[knightfly]

OK, only 35 more posts to go

From top to bottom : One layer of 'stuff' in the attic. One layer of 3/4" MDF screwed down, rockwool in the ceiling cavities, 2 layers of gypsum (1/2" & 5/8").

If you've not already done this, consider removing the ceiling wallboard and putting Resilient Channel on your joists before putting up the two layers under the joists - this won't make a difference in low frequency isolation, but will help mids/highs by about 6 dB - plus, unless you've just put the insulation in there, it's hard to know how much/what kind is there - for best isolation, you want somewhere around 2.5 to 4 pcf density, like rockwool or rigid fiberglass. Increasing insulation density will also improve damping and isolation by a couple more dB.

Well, that'd save me some trouble... What should I do about attaching the wall to the ceiling? Does the same construction for exterior wall/ceiling apply for interior walls to ceiling?

No, ideally you want your exterior walls and your upper ceiling mass (the plywood on top of the joists) to be one continuous barrier, with little or no connection to the inner leaf which consists of your inner wall panels and inner ceiling panels. So, the inner wall should NOT fasten to anything but the inner ceiling. You might check out Aaron's Basement studio thread for more on this, it's long but has a lot of good info -

What if I did a floating floor, framed with 2x4s, 12" on center, stuffed with rockwool, 1 layer of 5/8" MDF, 1 layer of hardwood flooring or ceramic tile, floated with rubber, neoprene or epdm? I was talking about the project with my boss at work, and she offered me contact info for a company that made the rubber feet they used for constructing a basketball gym floor.

That could work fairly well, although not to as low a frequencies as a floor with more mass or deeper joists - I'd use EPDM unless you know you'll be tearing it out in 10 years or less - I'd need more info on the gym floor pucks before I could guess how well they'd work.

Superduct. Separate runs. At least one 180 in the duct. Gotcha.

Almost - the turns in a duct should TOTAL at least 180 - but not all in one "U" bend, more like couple of 90's, maybe a 45 here or there... Steve

[jatougas]

If you've not already done this, consider removing the ceiling wallboard and putting Resilient Channel on your joists before putting up the two layers under the joists

Oh, this'll be fun to run past my stepfather. I'm going to guess my construction costs just went up from the $6k I was hoping to keep it to (not including gear).

You might check out Aaron's Basement studio thread for more on this, it's long but has a lot of good info

Will do.

That could work fairly well, although not to as low a frequencies as a floor with more mass or deeper joists - I'd use EPDM unless you know you'll be tearing it out in 10 years or less

I'd like to go with thicker flooring, but I've only got the 8' ceilings in there, and I'll be losing ~3" the ceiling, and at least 6" to the floating floor. I don't think I can afford to lose much more, before it starts to have serious repercussions on my recording quality. With this being the live room, I'm pretty sure I don't want to put a layer of wrapped 703's in there.

I'd need more info on the gym floor pucks before I could guess how well they'd work.

If I can find out any info on them, I'll pass it along (particularly if they're cost effective). My boss did mention they came in three consistencies : soft, medium, and hard. As far as what kind of absorption or compression factor that relates to, I couldn't tell you, but she did say we used the medium ones under the floor in the basketball gym and that the end result is cushioning enough that it's a more comfortable surface to play on. I think the hard ones were used under the volleyball court.

BTW, if my measurements of the beam were accurate (6"x10" or so) what do you reckon the weight per foot allowance is of that ceiling?

Thanks for your help.

[knightfly]

6x10 beam, how far apart are the supports for this beam? Steve

[jatougas]

6x10 beam, how far apart are the supports for this beam? Steve

Okay... actual, real world measurement of beam yields a 5"x17" beam, with 20 ft between supports. Joists are 2x8, 16 inch center.

That's what I get for relying on visual memory... yeesh...

[knightfly]

At rough guess, even a beam half that thick might support all you need; with what you have, whether it's glu-lam, solid, pine, fir, whatever, you should be good for several layers on either side of your 2x8's - and the 2x8's themselves will support up to 20 pound psf dead load, which would equate to about 7 layers of 5/8 sheet rock PLUS the weight of the joists themselves; so basically, not a problem... Steve

[jatougas]

At rough guess, even a beam half that thick might support all you need; with what you have, whether it's glu-lam, solid, pine, fir, whatever, you should be good for several layers on either side of your 2x8's - and the 2x8's themselves will support up to 20 pound psf dead load, which would equate to about 7 layers of 5/8 sheet rock PLUS the weight of the joists themselves; so basically, not a problem... Steve

Cool! So my lil stick built spec house is built to take it! Woohoo!