Week 114 (Sheetrock in Music Room)

In construction photos by Michael Tiemann

It’s hard to believe that we’ve been under construction for more than two years without cutting, installing, or taping a single sheet of sheetrock, but it’s true. Last week we took delivery of 10 tons of sheetrock and this week it started going up:


This week also saw some of the most intense work thus far, filling the parking lot with over 20 cars on some days, but I’m going to give the newest crew their due and talk first about the sheetrock…

When full-sized, the boards weigh 100 lbs, so it takes 2-3 people to lift it into position and screw it in:


As we’ve explained in the past, the sheetrock does not have a hard connection to the ceiling joists.  Instead, we have spring isolators that are fastened to the joists.  We then hang hat channel from the springs, and the drywall screws into the hat channel.  To recall, here are the spring isolators:

And the new 4′ on center grid layout that derives from our 2′ on center joists:

To hit these hat channels, the sheetrock crew have to carefully plot the hat channel locations on their boards before putting them up.  You can see the lines in this image, and the dead-center accuracy they employ when screwing in the drywall to meet the hat channel:


It takes a lot of screws to put up over 4000 sq ft of drywall:


Do you think 8000 is enough?  Remember, we also have to do the Annex in a month…

And now for the part of the story I cannot express in pictures…the acoustics.  Prior to the installation of the sheetrock, the Music Room ceiling was full of blown-in cellulose, which is pretty dead stuff.  Thus, the Music Room had some sound to it, but as live rooms go, it was pretty dead.  All that changed, and dramatically so, with the installation of a hard ceiling.  Designer Wes Lachot has been spending a lot of time on site (thanks Wes!) and as we passed through the newly clad ceiling, he clapped and estimated that our RT60 was now up to 3 seconds.  As the walls were going up he promised that the acoustics of the room would change, and change, and change again before being finally tuned. All of a sudden the live room is really, really live. That will change a lot when we install the acoustic cloud (some time between April and May). And the sound will also change when we add the 10 10′ tall RPG diffusor panels on the front wall and the 13 smaller panels on the other 5 walls.

In order to say more about how dramatic have been the changes to the sound of the Music Room, let’s look at the Control Room and the Booths.

In the Control Room we’re doing a dead instead of a live ceiling, so we’re using Iso-clips instead of Iso-springs. Here you can see the clips before the hat channel is installed:


Then the hat channel is installed, South:


and North:


But even at this stage the Control Room is beginning to take on its own characteristic sound.  The insulation filling our 2×12 rafters is dead, dead, dead, and it will stay that way when three layers of sheetrock are installed and the cloud and the soffits do their sound-eating work.  The front wall presently has a large void where the window will be (which is effectively a perfect absorber) and a large solid wall above that void.  This is upside down compared to what will be in the finished room: reflective glass and a hard wall below that makes up our RFZ, and an absorptive cloud above.  But on balance it’s about the same.  When one talks in the control room, one hears lots of diffusion and lots of neutrality in the response already.  It sounds very, very neutral, which is of course very different than the Music Room’s very, very live sound.

Moving over to the Booths, we see from the West side of Booth A that the walls now have their insulation fill:


If you click on the above image you’ll see a wider angle perspective.  Looking from the Northeast corner of Booth B, we see the other side of the story:


And the sound in there, and in Booth A, is dead, dead, dead.  When you speak in there, you can really hear the sound going out and not coming back.  Even the large block wall above doesn’t really reflect much, because the sound that bounces off from below heads into the ceiling, where it dies.  If we didn’t care about acoustic isolation, we could stop now.  However, since we do, we’re going to add 2-3 layers of sheetrock to these walls, and then 2″ of fabric covered 705 to tame what would otherwise be too much liveness in the walls.  The ceilings will be finished in TopAkoustic with 705 behind, preserving the deadness of the ceiling even with multiple layers of sheetrock above.

And now the fun part of tying these spaces together.  When you talk into the booths, you hear deadness.  When you are standing in the booths and you talk out to the Music Room, you hear the Music Room pick up the sound and keep it alive, while in the booth you still hear deadness.  So inside the booths you can hear multiple distinct acoustic environments at the same time.  Very cool!

Now let’s venture outside for a bit to see the progress there.

Good weather on Tuesday brought the roofing crew out to put shingles on the Annex roof.  Here they are getting the singles into position:


And from another perspective, the shingle packs piled up:


From that point forward it was just a matter of time.

As the roofing team made their progress, the masons, too, were positioning their materials.  They pulled apart several cubes of gray block, positioning groups of blocks to where the foundations for the North patio would be laid:


In go the blocks:


Up go the shingles:


And before you know it, matching roofs:


And a good start on the North Patio foundation:


But wait!  There’s more…

Wires are pulled into electrical conduits:


Making their wall to the junction boxes in the walls:


And still more…when the variable weather (and changing landscaping plans) proved unfavorable to further block work, the masons shifted their focus to preparing the Annex slab.  The first step was laying down the vapor barrier of plastic and the insulation layer of foam:


Then holes were drilled for the placement of rebar chairs:


Then the holes were filled with chairs:


And some other sub-slab adjustments were made:


Not to mention the prep work done by the carpenters to prepare the Cypress that will soon be installed into the lower exterior soffits:


So this is where we wind up this week:


All in all we seem to be relatively on track for an opening in October 2010.  May it be so!

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