[GSBN] prefab strawbale

[cmagwood at kos.net]

Hey all,

Very interesting to see this prefab discussion pop up! As some of you
know, I've been working on a prefab system for a while, and finally got a
chance to put to work on a full scale building this summer.

I've seen the Modcell system, and have many of the same reservations as
have been expressed here on the list. It seems a lot of material and not
much savings.

Our system here is just a typical load bearing wall that's made off site.
We use minimalist 2x4 box beam top plate and 2x4 sill plates, so there's
no more wood in the wall than any other building, and in fact much, much
less than any of the framed bale wall systems. In fact, it was watching
people ignore good old load bearing walls in favour of heavily framed
systems that got me wanting to prefab in the first place. I thought that
if we could eliminate the two complaints of weather protection and
wobbliness, then everybody could do load bearing.

In terms of transportation... all the bales, lumber, sand and masonry
ingredients get shipped from a source to a job site. Whether those
materials come to the "factory" first, get assembled and then continue on
to the job site seems pretty minor. In some cases, it may lower the EE,
sometimes make it a tiny bit higher, but not enough to discount the idea
of prefab. One of the beauties of our system is that the "factory"
requires only typical job site tools (chop saw, table saw, screw gun,
mortar mixer) and some floor space. Micro-factories are the way to do
this, not big centralized plants.

Our walls went together (with student workers, most of whom had no
building experience) in 1/4 of the amount of time we'd usually spend doing
site baled work. They turned out consistently sized, square, straight,
load bearing panels for less than the cost that any builder could make
standard frame walls.

You can check out photos of our system on the Photo Album section of the
class website at www.sustainablebuilding2009.ca. Those of you who've seen
me present on this subject know that I'm pretty enthused about it. After
too much time putting up test sheds, now that I've got a real building
done this way, I'm only more enthused than ever!

Chris