The Green Dream Gets a Third Floor

It finally looks like a house! Here's a look at the final push to the get the dry box up before the snow flies

By John B. Carnett | Published Dec 3, 2009 12:45 AM

A snap from our time-lapse rig shows all the third-floor and roof panels in place and the Zip board going on . . . John B. Carnett

I can’t believe it, but the entire box is now up. All the wall and roof panels have been installed. As you may recall the second floor was a bit of a learning curve for everyone, but when it came to the last level, everything went together as expected. LightShip Group, the firm making the panels, took all the field experiences that we had with the first install, went back to the shop and turned out 100 percent perfect panels for my third floor walls and roof. Click the gallery for shots of the third floor and it’s curved roof section going up, and see more details about the build after the jump.

Here are a few highlights from the final push:

• Light Ship eliminated the “C” channels that had been on all the interior walls and instead used a two-inch angle. That really helped speed up the install process: We no longer had to cut channel in the field. Rather, we just had to unscrew and flip around the angle that was already on the panel from the factory. It was a brilliant solution, but it was too late for all my exterior walls that have the “C” channel. Any cold that hits the outside of the channel goes right under the panel and into the interior with no thermal break. I intend to fix this by running a strip of Aspen Aerogel along the entire interior where the channel enters the house to create a thermal break. Like I say, lessons learned.

• Lightship also provided pre-cut metal corner connections for all the panels this time around. That saved a bunch of time as we could just slap down the metal and go without having to stop to cut raw material. My chop saw can finally rest.

• They also designed an in-house crane hoist bracket that allowed multi-wall panels to be connected on the ground then lifted into position as single units.

• My third floor roof is 11 inches thick and it carries itself all the way down the roof to the north vertical wall over a curved radius. That not only gives me an incredibly high R-50 insulation rating for the roof, but also for the back wall. It’s an amazing feeling to stand in a corner of a building that is under construction and feel warm.

• I elected to use the same panel material in four-inch thickness for my interior walls. This allowed everything to go up at the same time and was a really effective way to deal with the ceiling curve connecting to the interior walls. You can imagine how long it would take to frame that kind of radius with typical 2×4 framing methods. I ended up with very tight walls between the roof and the interior, which will help control not just temperature but sound as well for a very peaceful bedroom.

• During the third-floor install I started counting the number of cans of 12 oz spray foam that we used. It took more than 81 cans to connect all the panels. Lesson learned: Remember to include spray foam in your budget!

• Just as soon as the Kama panels were installed, we began getting Zip board on the roof and exposed walls. The curved corner on the roof was too tight for the zip board so we used 1/4-inch AC plywood in two offset layers then covered it with a waterproof membrane, which matched up perfectly to the Zip Board.

I’m looking forward to getting the doors, windows and metal roof on next. In the meantime, check out the gallery of the third floor going up here.

John B. Carnett, PopSci’s_ staff photographer, is using the latest green technology to build his dream home. Follow along as the project progresses on his Green Dream blog: popsci.com/green-dream_

Panels, Panels, Everywhere

This time around we spent a bunch of time pre-positioning the panels to get them more closely in order; this ended up saving us tons of time. Of course, we learn that lesson on the last floor . . .

Looking Down Into The Third Floor

The view down from the crane you can see most of the interior walls in place and an 11-inch-thick curved roof panel about to be slid into place.

Third-floor Interior Walls

These are the 4-inch-thick interior walls prior to the roof being installed. It’s not typical that interior walls have insulation, but it’ll really help keep the bedrooms soundproof and warm.

The Curved Roof Panels

This gives you an idea of the scale of the curved panels (one of the benefits of the Kama system). It took four guys to lift each one. We ended up attaching a metal eye to the center point with a bunch of truss screws and dropping it into place.

Lifting the Curved Roof Panels

We used a crane to drop the curved roof panels into place.

Installing the Curved Panels

Here you can see the radius of the two curved roof areas. If you look closely, you can see hundreds of metal truss screws that fasten the Zip board—the outer coating—to the metal in the kama panels; it’s a slow process.

Inside the Third Floor

From the inside of one of the bedrooms, you can see the radius. Imagine the sunlight bouncing off this as it enters the room from the opposite window.

Looking Into the Third Floor

Looking into the third floor from the south, you can really start to envision how the spaces will open up to the natural light from the large window openings.

Flying in the Panels

Another shot from our time-lapse rig shows a two-story tall multi-section panel being lifted into place. The ability to assemble these tall sections on the ground then “fly” them into place saved time and made for a very safe way to build.

View from the South

The house looks a bit strange in this shot because I let the Zip panels cover up the rough openings on some of the kitchen windows. It’s hard to understand where the actual windows will go, but trust me, there will be some!