Week 10 - First floor framing

Don, the carpenter, was able to get a bunch of work done early in the week before the weather turned cold and stormy. He’s basically got most of the first floor framing done.

Interior framing first, then exterior walls will go up

Last time I talked about how the walls for the home are SIPs walls — prefabricated walls panels. So now why is the carpenter putting up walls the old fashioned way? Let me explain.

The architect has designed the walls to consist of two components: the exterior walls, which are the SIPs walls, and the interior walls, which are constructed onsite with 2 x 6 lumber. The interior walls will contain extra insulation and provide a frame onto which the SIPs can be attached. Also, the first floor walls will hold up the second floor. Once the first and second floor framing is complete — probably in 2–3 weeks — the SIPs will be installed with a crane and attached to the interior walls.

Why two walls?

I’m not exactly sure why the architect decided to go this route, but the hybrid interior-exterior wall design seems to have a number of advantages. First, the interior wall increases the total wall thickness, boosting the R Value significantly. I’m assuming that it would be tremendously difficult and expensive to fabricate and install a wall panel that was 14 inches thick — the total thickness of both walls. Second, the interior wall will accommodate plumbing, wires, outlets and light switches, so that the integrity of the outside wall can remain intact without needing to drill channels in multiple locations. Third, the interior wall assembly is vastly simpler than a conventionally framed wall because it only contains studs and plates — it doesn’t need nogging for extra support.