New home theater project - need framing advice

I’m about to embark on a home theater project, and I could use some advice (probably quite a bit, actually!). The basics: the theater will be built in a “bonus room” that sits over a three-car garage. Room dimensions are approximately 28' x 15' x 9'. Here are a couple pics of the space:






(BTW, the small windows at the end have since been filled in.)

Here’s a few SketchUp shots of the general concept I have in mind (still early, and very much open to change… if you have any general suggestions, I’d love to hear them!):

http://picasaweb.google.com/lh/photo...eat=directlink
http://picasaweb.google.com/lh/photo...eat=directlink
http://picasaweb.google.com/lh/photo...eat=directlink
http://picasaweb.google.com/lh/photo...eat=directlink

Right now the room is still unfinished space. My general idea was to go with staggered stud walls, with probably a couple layers of 5/8” drywall. I had the builder use 2x6 for the wall plates, so I think I should be OK putting in the second set of “interior” studs. However, one major question I have is: how should I go about “finishing” the lower section of the walls? As you can see, the lower section of the walls is currently “open” to the eaves (i.e. the outdoors):









I think I’ll want to put some sort of backing in these spaces, on the “exterior” side. Because of the way the room is framed, though, I can’t think of an easy way to accomplish this. The obvious but tedious solution would be to cut individual pieces of plywood and nail them in between each pair of studs. However, this would be a huge, time-consuming pain in the butt. A friend suggested maybe using some sort of flexible material (e.g. Tyvek) that could be snaked through the framing and stapled in place. However, I am concerned that having such thin material there would compromise the soundproofing. (I will be putting some sort of insulation in the walls, though I am not sure what sort of material yet…) Anyone have any other ideas?

Yeah, I was thinking those headers could be a problem. Unfortunately, I was unaware that they were going to be there until the house was already built. I'm not really sure why the builder felt it was necessary to use those, they seem like overkill just to support the relatively small roof on top of the bonus room. But anyway, what's done is done. One upside is that I got an extra foot of ceiling height.

I guess I could still use clips and channel. I gotta put another set of studs up regardless, so I 'll be staggering them anyway.

re: equipment; yeah, the plan is for that little room in the corner to be the equipment room, which would be accessed through the bathroom as you surmised. It would have a rack/shelving and an an opening facing into the theater to allow access to the front panels of the gear, etc.

re: HVAC; the house has two AC units (actually heat pumps; I live in Florida), and one of the units was sized to be able to support the bonus room. That unit is currently servicing three small bedrooms in the main house; there's a damper and separate thermostat installed in the bonus room (it'll be a separate "zone").

Wow, lots of great feedback here already!

Just to give a little more background... one the issues I had with the notion of doing a home theater is that my house is not a true "custom-built" house. The builder I used has standard models of homes that they build, and the "options" are fairly limited. So, for example, on my house they offer a standard "bonus room over the garage" option, but when I started to talk to them about things like stagger studded walls and so forth, I got lots of blank looks. If I tried hard enough, I could sometimes get them to deviate from their standard plans and procedures, but in a lot of those cases, they would go off and cost the modification, and the prices they came back with were often pretty outrageous. I did get them to make some minor changes to the bonus room (e.g. the aforementioned 2x6 wall plates, as well as eliminating most of the windows -- there is now just one minimum-egress sized window). Originally they were going to finish the room, but when I started making too many "bizarre" requests, they eventually said, hey, what if we just charge you less money and leave the interior of the room unfinished, and after you close you can do whatever the hell you want in there. In retrospect, I'm really glad it worked out that way, it's given me a lot more flexibility, and time to think things out more thoroughly. Which of course has led me to come here and ask you folks for ideas!

re: AC; thanks for the tip on the acoustical duct, that was one of the questions I had on my list to ask later. I'll likely have some other questions on this front; i.e. techniques or materials I might use to minimize sound leakage to the main house through the AC system. I've heard the tip about 90 degree bends that Moggie mentions, and I'd be intrigued to hear more about the use of MDF there. As for the capacity of the AC unit, I did discuss the planned usage of the room to the AC guy who sized and installed the system. I believe it's a three-ton unit, which in addition to the bonus room will be cooling three bedrooms that are roughly 130-150 sq ft each (hopefully that's enough cooling; seems like it to me, though I'm certainly no expert).

re: using that flexible insulation product as a backing on the side walls; that seems like a good possibility, it's a similar idea to what my friend suggested about using Tyvek. It certainly seems that it would be relatively easy to install, compared to the hassle of cutting and nailing plywood into each bay. My main concern with using a product like this would be the lack of "mass" making the walls less soundproof. Granted these are "exterior" walls, although that open space in the eaves is right over the ceiling of my garage, and there is currently no form of insulation there. Is there some kind of wall insulation I could use that would help "make up" for that lack of mass? Or am I worrying too much about that?

re: the riser; yeah, you can pretty much disregard what I have in that drawing, it's just something I threw in there as a placeholder. I haven't done any research into proper riser design yet. I'll definitely take a look at what you (and others here) have done.

BIGmouthinDC & dc_pilgrim: thanks for your feedback on the floor plan, those are some interesting ideas. I'm definitely not beholden to the layout of the snack and equipment areas as shown in my drawing. I'm particularly intrigued by the idea of maybe allowing for a third row of "bar seating" back there. BIGmouthinDC, in answer to your question: the bathoom/sink are indeed pre-plumbed, but the drawing is a little out of date; the plumbing is actually not along the back wall, but at the approx. location of the planned "opposite" bathroom wall (i.e. same area as the "back wall" of planned snack area). Of course, the plumbing could probably be moved if necessary. I'll take some photos of that end of the room and post them here.

Thanks again everyone for all the feedback so far, this is really helpful!

OK, here's a couple updated SketchUp shots reflecting the "actual" location of the pre-plumbing:








And here's a few photos showing the rear of the room, including the pre-plumbing. FYI the (open) door on the right is the stairway to the main house, and the (closed) door on the left is to a small room containing the AC air handlers (i.e. a noise source that I will need to contend with).

Tedd -- hmm, the "elevating the floor" concept is interesting... how much elevation would be needed? Do I have enough ceiling height (9') to make it feasible?

miltimj -- actually, I don't have any neighbors at all at the moment; I'n in a new area, and the housing market tanked pretty much simultaneously with me closing on my house. But I probably will have neighbors at some point. And they will be relatively close... not sure exactly what the setbacks are offhand, but they are pretty minimal as I recall.

re: the equipment room; I didn't have any explicit purpose for the extra space in there, other than some vague notion about storage, etc. But I like your thought about possibly expanding the bathroom instead...

Behind that second door is just a small closet containing the air handlers for the AC system.

Thanks for the feedback, guys. I'm going to try to create some alternative versions of my current SketchUp model incorporating some of the ideas that have been thrown around here. I'll post the results here for further comment / discussion.

Okay, I've got some revisions the to my original concept, incorporating some of the elements suggested here (thanks everyone!) I've posted some images of the revised layout in a new "design" thread here. I'd welcome any feedback or suggestions.