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The Phoenix Theater Build Thread - Page 2

post #31 of 42
blank canvous let the fun begin biggrin.gif
post #32 of 42
Subscribed. Excellent documentation. I kinda suck at that. What speakers are you planning on going with in your new space? I'm an M&K guy, too, but was looking at some of the DIY Sound Group stuff as a possibility down the road.
post #33 of 42
Thread Starter 
I haven't yet decided on the speakers, other than I'm going to make them myself. Subs, too. It's most likely that I'll decide on which ones just before I actually start building them.
post #34 of 42
Thread Starter 
Ah, nothing like crippling indecision. One of the reasons I put off quite a bit of decisions until the last possible moment is because I know myself -- I know that I will agonize over a steadily expanding tree of choices and never be able to make any decision at all. So I just take it one step at a time, to allow myself some kind of progress.

Well, I'm at one of those stages where I need to make a lasting decision, but I keep wildly flip-flopping between the two non-ideal possibilities. I do have a few more bits I can do... but since this involves the walls, I need to decide very soon.

Okay, so three of my four walls are exterior walls and thus need to be insulated for thermal efficiency in addition to for soundproofing. Very technically speaking, I can get away with the normal R-13 used in the soundproofing component since I'm in AZ and that's all that is needed for walls. I want more, though. So I bought some sheets of 1" Polyiso rigid foam which is somewhere around R-6. That'll give me R-19, which is just about perfect.

My original plan was to glue the foam to the slump block exterior walls. My full wall setup would then look like so:

7.5" Block + 1" PolyIso Foam + 1" air + 2x4 frame w/ R-13 fiberglass + OSB + GG + DW

Looks good, right? Well, I have an open attic above my theater and that causes all sorts of problems. Because it's open, that means that the 1" of air space in that wall setup is now essentially attic space. Attic space gets up to 160 degrees in the summer. If I had a pocket of 160 degree air between my foam and my fiberglass, then doesn't that completely invalidate the foam? Now, it wouldn't be quite like that since I'm going to have to seal off that 1" air gap no matter what, or else my blown insulation will be falling into that crack. I was planning on putting a piece of drywall across that gap, which will stop any insulation from falling and also act as a fire stop. But even sealed, that drywall isn't going to provide much thermal resistance. It's prevent conductive heat transfer, but since the insulation on top of it will be minimal (it's where the roof meets up with the wall), there will still be significant amounts of heat radiating down into that space.

So I'm now flip-flopping on another plan. What if I attached the foam directly to the 2x4 wall? Then it would look like so:

7.5 Block + 1" air + 1" PolyIso Foam + 2x4.... yadda yadda

In this case, the foam would be sealed to the 2x4 wall and so I get 100% of the thermal efficiency. The air pocket would still be notably hot, but who cares because my R-19 is there to slow that heat transfer down (instead of just R-13 from before).

Even better? Well, it has the notable problem of how to transition from the exterior walls to the interior wall. There would be notable gap of any insulation right at that point where the exterior wall continues past the insulated inside wall. That happens on both sides of the room. This could easily make my non-exterior wall the problem area for thermal efficiency.

Maybe I could work around that by stuffing some fiberglass in the air space right at that point where the exterior walls meet the interior walls. That should keep the super-heated air from making the corner into the fourth (cooler, interior) air pocket.

But if I'm going to be stuffing insulation into gaps, then why don't I go with my first plan and stuff insulation right underneath the drywall topper. It would be wedged between the foam and the 2x4 wall, but only the top few inches. That could give me my insulation on the top and allow that air space to never get super-heated in the first place.

Flip-flop. Flip-flop.

Neither solution is obviously superior to the other from my perspective. I need to choose one of them sometime in the next week, though.
post #35 of 42
Wow. My head hurts and it's not because of the booze this time.

Have you thought about paying a few hundred bucks and having a consultant advise you? Maybe a mechanical engineer that designs HVAC systems or maybe a really knowledgeable HVAC technician? Might be worth a few hundred for someone to come out and take a look.
post #36 of 42
Thread Starter 
Minor Update - Mar 23, 2014

I didn't get a lot of time to work on the theater this week, due to it being so nice outside. What's that got to do with it? Well, the trees need pruning, the weeds need addressing, the grass needs cutting, the pool needs maintenance, &c. Gotta do it before it gets hot. Gotta get the theater sealed in before it gets too hot, too... but that's far less likely.

Anyway, I did spend more than a little time going back and forth on where to put the rigid foam, as evidenced in a previous post. For actual work, I removed the very last tiny bits of the old stuff to make it 100% deconstructed (i.e., I'm not expecting any more old debris from the room anymore).

I also attached some particle board to the hall wall above the false lowered ceiling of the hall. That is, I had already attached particle board to the part of the hall wall that's below the ceiling (and taped and mudded it), but the part that was above the wall in the attic was still open. Enclosing it doesn't matter a whole lot from a soundproofing perspective since it's sort of just hanging out there... but it will keep the blown in cellulose from tumbling into my double wall air space. I didn't bother doing a careful job of sealing it -- just a single layer of tape and mud where there were a few egregious cracks. Again, that's just to keep the upcoming cellulose at bay. I did need to do some careful cutting on one of the pieces, to fit it into the existing space, jigsaw puzzle piece style:

Sheathed above the hall ceilingJigsaw puzzle piece

And I reaped the very first benefit of what I sowed earlier. One of the main purposes of my deconstruction vs demolition was to be able to re-use as much of the components as possible. Now was the first time that I could re-use something -- the insulation. I filled in the hall way bays with a dual layer of insulation. It had to be a dual layer because the reclaimed insulation was all behind a 1-3/4" wall (just strapping) and so it's half the thickness of normal R-13 fiberglass. Not all the pieces were full length, either, so there's a lot of patchwork. It wouldn't be ideal as a primary thermal barrier, but it should do the job nicely as an absorption layer and as an air pocket "multiplier" in my dual wall setup:

Insulated hall wall

Note the polyiso foam hanging out on the side, there. I think I may have come up with a decision on that front. I'm going to go with my original plan. The way I see it, since I have two plans that seem equally good and equally dubious and I can't decide which is better on their merits, then I might as well go with the one that I already made up a Sketchup model for. Oh, is that a silly reason? Yeah... but hey, it beats flipping a coin. I'm going to start gluing the panels to the wall next week. They will each be 1-1/2" inch off the floor to make them even with the top plate on the exterior walls, and then I'll fill in the gap on the bottom with Great Stuff expanding foam.
post #37 of 42
Thread Starter 
Update - Mar 30, 2014

I attached the polyiso rigid foam on all exterior wall surfaces. It took longer than it would for most people, largely because I am more of a perfectionist, even for something like this. At first, I applied the glue (PL375) in globs to the back of the foam itself:

Glue on foam

It needed to be in rather large globs since the wall was so bumpy and this increased the chances that more of the glue will make contact with both surfaces. As is, quite a few of those globs still never touched, so I didn't do it like that the entire time. It went through a lot more glue than I originally thought, too. See, I originally bought the standard 10oz cans and I assumed I'd be able to glue up three 4x8 pieces per can. I eventually got a 28oz caulk gun and so I returned those and got only a couple of 28oz cans of the glue. It turns out that I drastically underestimated how much glue I'd go through, as the 28oz can (three times larger than my original 10oz cans) only handled 4 pieces. That meant that I would have gone through an entire can for each piece of foam, originally!

Handily, though, I was able to use normal construction adhesive and not the "foam board" crap. That's the blue stuff. I used that some time back and it was absolutely useless. It's needed for EPS or XPS foam, though, as normal construction adhesive will "melt" the foam. Polyiso has an aluminum foil backing which prevents that and so I could use a variant that actually worked.

I pressed each piece against the wall and then put weight on the top of the foam using a 2x6 and the bottom using a piece of slump block:

First piece of foam up

Yeah, that's a laser level. My wife was incredulous that I'd use a laser level on a piece that will never be seen after the walls go up. Who cares if it's perfectly plumb, she asks? Well... I don't have an answer for that other than I care and the reason it needs to be plumb is "just because it does."

Note, too, the shims under the bottom. My original plan was to put the foam on a 2x4, so it was 1-1/2" up and level with the top plate. It turns out that the walls aren't exactly the same height all the way around and so the foam sheets wouldn't be flush with the top plate in all cases. I decided, instead, to consistently shim the foam up 1/4" on the bottom and to leave a gap of an inch or so on the top. I would then spray expanding foam on the bottom and the top to fill in the bottom and even off the top.

There was one outstanding area that I wasn't sure how I'd handle until I got to it and that's where the wires snaked down the wall for the exterior coach light, door bell, and outlet box:

I ended up just gluing a panel right over them. I figured that they were hidden behind a wall before and so they would be hidden behind a wall again. After the glue had cured, my wife brought up the point that maybe the difference is that now the wires are glued in place and before they were free in the stud bay. The latter case would be easier if we ever need to replace the wire. Maybe. On the other hand, the wire is cemented into the wall and so it wouldn't have been trivial to pull it up no matter what.

After the first day (and first can of glue), I decided to start applying the glue directly to the wall. That way, I'd know to hit the high spots and guarantee better coverage. Since it's not hit-or-miss, I also ended up using less glue:

Glue on wall

In this case, the laser line actually came in handy for letting me know where to apply the glue. You may or may not notice that my shims are slightly different. I switched to using a length of 1/4" plywood and then inserted normal shims as needed to get the pieces plumb. The 1/4" plywood lengths will later be used when doing the drywall/OSB layers.

At this point, getting all of the necessary 2x6s into position to keep pressure on the foam was becoming increasingly tricky. Each piece is 12' long, so moving them around all of the existing pieces was extremely tricky. It was a veritable forest of 2x6s:

Forest of 2x6s

After all of the foam was up, I started on the gaps using Great Stuff expanding foam. I had purposefully left a 1/2" or so gap between the foam in the corners because there was no way of getting those to be tight. I filled in those gaps with foam:

Foam in gaps

I don't know if you can see it in the picture but there are some areas there where the foam didn't expand very much and left gaps. Those gaps have been a constant problem for me as long as I've used Great Stuff (which is a decent bit). Sometimes it works like a charm and sometimes it barely expands at all. I have never been able to figure out what the difference is.

Well, a few minutes ago, I saw some videos by Dow that might have shed some light on this. They claim that Great Stuff requires at least 50% relative humidity in order to cure properly, or else it will shrink. This is Phoenix AZ we're talking about, and 50% humidity just ain't happening! So next time I'm going to spritz it with some water and see if that helps or not.

I also finished up a can by spraying underneath the panels to fill the 1" x 1/4" gap. That seemed to work fine. I actually have a "pro" gun for Great Stuff which is a lot more precise, but since I have a couple cans of the normal stuff, I figured I'd use them first. I do still need to do the next half of the room.

I likely won't apply the foam to the top of the panels until I build the walls... for reasons.

Oh, I also taped all of the seams with house wrap tape, to prevent air gaps:

House wrap

When all's said and done, it looks like so:

Final foam paneled room

I still have one full sheet of foam that I don't know what to do with, plus a bit of left over. We'll see.

Next week, I'm going to finish off applying the expanding foam where it could use it. I'll also look into replacing all of the newish white fiberglass with the old pink stuff, since the new stuff will likely fit better in my upcoming interior wall. While I'm at it, I'm going to attach some leftover pieces of drywall to one of the common walls, just to give them more mass (and why not, because it's all scrap drywall that would otherwise go in the trash). At some point SOON, I'm going to need to paint those windows. That needs to be done before it gets too hot.
post #38 of 42
Looking good Granroth... Let me know when your ready.. I got a drywall lift that ill pass along..
post #39 of 42
Thread Starter 
Very Minor Update - Apr 13, 2014

I haven't made a huge amount of progress on the theater, mostly for two reasons. First was a full week mostly gone doing taxes -- hours of tracking down and scanning receipts and then finding out I did the taxes wrong, along with doing last year's taxes wrong, and having to file a 1040X "amended tax return" and all the fun stuff like that. I finally got past that... and wasted almost a full week being sick and barely able to stand on my own two feet for more than a tiny bit in the heat of the theater (we're officially at over 100 in the theater space every afternoon now). So yeah... not a lot.

My wife and I did get to sneak in (finally) painting the two windows. They are both fiberglass, but have a faux wood finish called "EverWood" that is stainable. We got that (and even paid extra for it) because we had some grandiose plan of staining it cherry or walnut or something like that. It was only after we had them installed and looked at what those would look like in wood colors that we realized that it wouldn't match our house at all... and so we have resorted to painting them with a black latex paint, completely wasting the expensively stainable aspect of them.

Anyway, they start out looking like so:

Bare windows

We taped up some of the important bits and then put on two coats of paint, followed by one coat of polycrylic. They are all water based layers so we only need to wait a couple hours between coats... especially in the extreme drying times given our dry and hot weather. Notably, we did not tape the glass at all this time and made a concerted effort to purposefully overlap the paint and clear coat on them:

Purposefully messy window

The intent of this is to form a film of paint and clear and then just smoothly scrape it all off in one go with a razor blade. And.... it worked fantastically! We got a clean line that no amount of careful taping could have accomplished and it was very quick. Unfortunately, I have no good pictures of that (yet). But take my word that the line is just about perfect. These are the last two of eight windows and we're kicking ourselves for not doing this for the other six.

The other thing I accomplished, then, was beefing up the short common wall a little bit. There is one span off wall that is roughly two feet wide that is shared with our living room and has a direct line of sight to the bedroom hallway. If there was ever a weak spot in the theater, it would be right there. I'm going to do three layers on the inside in that spot, but I figured that since I had some spare bits, I might as well add some mass to the existing wall.

I had actually saved some of the drywall from the closet I tore down and so I cut some pieces out of that and glued it between the studs:

Added drywall

It's only 1/2" drywall and there's not a great fit and I didn't do any caulking or Green Glue... but that's not really my goal, here. My goal is to just add some "free" mass from bits that I had left over.

For a second layer, I got out some leftover 3/4" particle board (like what I used to build the outside hall wall) and glued that up. I was full blown sick at this point and this required ripping to width on my table saw... which probably wasn't a good idea in my state. But I did it anyway:

Added particle board

In the end, that wall ended up being 1-3/4" thick (two layers of 1/2" drywall plus one layer of 3/4" particle board) giving me roughly 5psf -- which is better than nothing and I got to reuse some scrap without having to toss it.

Next week, hopefully I'm well enough to actually start framing the inner walls!
post #40 of 42
Thread Starter 
Originally Posted by KNKKNK View Post

Looking good Granroth... Let me know when your ready.. I got a drywall lift that ill pass along..

Oh, sweet! I'm probably a few weeks out for that... maybe a couple of months. I've already resigned myself to the fact that I'm going to be working without A/C in that room when it's 115-120. C'est la vie.

It's funny, though -- I saw in your profile that you list AZ but when I read the first couple pages of your build thread, it was all about your theater in Indiana and so I just assumed that the AZ tag was from before (or something?) After your drywall lift offer, I finished reading through your build thread to clarify my confusion and sure enough -- you are likely just south and east of me, since last summer. Nice!
post #41 of 42
Wow - quite the build!
post #42 of 42
Thread Starter 
A Tiny Spark

One thing about soundproofing is that you can't really know how well it will work until you are completely done. I can make some educated guesses by comparing the walls I make with existed tested walls... but even then, it won't be the same. Every single detail matters so much that any deviation from the tested wall will end in a different result.

I did have a infinitesimally tiny taste of what might be, this evening. My above post was about how I added some 1-1/4" of extra mass to the short common wall with our primary living quarters. I was curious how much of an impact even that little bit could make. The reason that occurred to me was because I was standing around that area and gradually realized that while I could hear what was happening in the living room pretty clearly (my son watching TV and my wife on the phone), I wasn't hearing it from the direction of the wall. Instead, the sounds appeared to come from the open doorway (I don't have a door to the theater, yet). That meant that the sound would rather go down some 25 feet of hallway and make three right turns rather than take the 5 foot straight shot through the wall. I decided to test this a little bit.

I got out my shop-vac and placed it one foot from the wall and turned it on. From one foot away, I measured just under 80dB and a FFT graph showed a surprisingly flat frequency set. I then walked over to the living room and stood opposite to the wall -- so roughly two or three feet from the running shop-vac. From that vantage point, I could clearly hear the shop-vac (roughly 55dB) but it was entirely coming from the hallway. I couldn't hear anything coming from the wall... even though we're talking 80dB less than three feet away! I could hear it clearly if I pressed my ear to the wall, but it was by no means loud.

The fact that such a tiny bit of soundproofing (and such an ad-hoc method, at that) would give such an outsized result definitely picked up my mood.

You see, I'm overall getting a bit pessimistic about what my end result will be. I essentially have three goal levels that I could meet. The highest level is where I would be thrilled by the result. The second level is where I'd be happy with it. The third level is where I'd be okay with it.

Result Oriented

A thrilling result would fit this pattern -- I have a movie (or trailer or whatever) playing in the theater at maybe 85 or 90dB (maybe a little less) when people come over. As they approach the theater door, they cannot hear any indication that there is something playing. As I open the door, though, the sound just pours out and you realize that that complete silence was masking something that was pretty darn loud.

My happy result would be if you could feel the bass outside of the theater and maybe some moderate rumbling, but that you couldn't hear that it was playing at all on the other end of the house (the bedrooms).

My okay result would be if you could clearly hear that something was playing, but it was indistinct enough that you could treat it as white noise and still get to sleep and not be bothered by it.

At this stage, I'm fairly certain that I won't hit my thrilling result and am increasingly worried that I might not even hit my happy result. I darn well better hit at least my okay result!


The problem is the flanking. I'm designing this to be a room-in-a-room with floating joists, which should give me the best reasonable decoupling. But here's the problem -- I'm not actually doing true floating joists and it's not a true room-in-a-room! The problem is the fact that I'm in a single story house and the space above the theater is my attic.

See, when most people talk about floating joists, they are referring to the fact that they are threading the joists in-between the floor joists from the floor above them. This creates a Mass-Air-Mass setup, where the theater ceiling is the first mass and the floor above is the second mass.

I don't have any floor above me. There is just Mass-Air... and that's it. There's no other mass. That means that the sound could go up through the ceiling into the attic and then scoot across the wide open space to anywhere in the house and dart down into another room, completely bypassing my beefed up double walls.

I asked about this on some hard-core soundproofing/acoustics forums, but the only real solution I got was one that I can't implement due to space constraints (building a "floor" above my theater and sealing off the theater from above).

Based on this, I'm pretty sure enough sound is going to escape through the ceiling to invalidate my thrilling result. The big question is if enough will be enough to block the sound from getting into the bedrooms.

Maybe Still Happy

The only reason I think I might still get my happy result is thinking about the attic as a much bigger "wall". For sound to get from the theater into another room, it would need to go through 5/8 DW+OSB (my theater ceiling), then R-50 of blown cellulose, then 5 to 50 feet of attic space, then another R-50 of cellulose on the way down, and then another 1/2" DW. That's arguably a Mass-Air-Mass setup from that perspective, albeit with a lot of Air and only a little bit of Mass on one side.

But here's the deal -- I won't know until it's actually done and it's already at a point where it's too late for me to do anything about it. Hrmph.

C'est la vie, I guess.
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