Prelude: Why clay/straw? It is natural and will return to the earth one day. It is very fire resistant because all of the straw is covered in clay. Mice don't like eating straw covered with clay and lastly, it breathes---the moisture wicks in and out of the building making it very healthy. The question: what happens in the Anchorage area? Will the clay freeze and crumble? We don't think so. But life is always an adventure, right?
What a glorious day it was to
work on a clay/straw model of this summer’s greenhouse project. I went down to the garage early to build the
frame of my model greenhouse. Since
we’re going to have 2x8 walls, I found scrap wood that might represent
2x8. I then scrounged for some sticks to
use as lathe strips and found my old 1/2x1/2 sticks I used for Christmas decorations
one year. I nailed them all together
with tiny nails. Some holes I had to
predrill so they wouldn’t split. 
I had made a cardboard model
the night before so I had something to go by.
I wanted the cardboard to fit on the outside of the model, so that we
could see where the terraces were going to be.
Alas, I didn’t plan on the thickness of the wood----I’m sure it’s a
common mistake. I took note to change my
Google Sketchup to show the thickness of the walls.
I finished the other side and
was ready for the class to begin. I
noted that had I been a better carpenter and better at planning out my pieces,
I would have had shorter 2x8s at each section to denote the falling slope we
are building the greenhouse on. I
could have put a piece of roofing on it so that it would slope. But, such is life. I didn’t like to use that scary circular saw
very much anyway.
My workshop participants
arrived and we were ready to start. I
introduced them to the 4 different stations I had set up. One was breaking up the hard clay, another
was mixing the powdered clay with water to create slip, and another was cutting
pieces of straw to provide the cob with tensile strength. Next was the
straw/clay mixing tub, to mix the wall insulation. We carefully looked over the pucks we made at
the last workshop and chose the recipe we liked the best. Finally there was the tarp with a bag of
rough sand and ¾ in. rocks. Once the
slip was ready, they could start making mortar.
It wasn’t long before we moved all the
stations outside into the sun. The
garage was too cold and we didn’t want to shut the garage doors and leave the
sun outside alone. So… everything came
outside.
The clay had been stored in
the garage and it was VERY cold to mix.
Note to self: next time buy some
rubberized gloves.
We tried mixing the
clay/sand/rocks in a tub. For the real
greenhouse, we’ll use a concrete mixer.
For the first batch of
clay/straw, Bridget used her hands. She
and Ian kneaded it much like you would knead bread.
It was such
cold work on the hands, we pulled the tarp outside too.
We ended up
with a model that looked like this.
Obviously we should have waited for the inside straw/clay to dry before
we put the outside covering on it, but we did learn that even though it looks
goofy, apparently it’s good to have straw sticking out. That straw collects the
rain drops that might otherwise run down the side of the structure and allows
the drips to drop away from the clay walls.
So, maybe the inside walls will be nicer/smoother looking. But we saved that for another day.
All in all,
it was a great day playing in the mud!
Next big task: melting the snow
on the building site. Ashes anyone?
(I'll go and take another picture from the top down, so you can see the clay/straw stuffing on the inside of the frames. It was fun!)
** If you would like to learn how to do this, you can sign up now for the first of several workshops this summer: http://www.eventbrite.com/event/6280935447
If you want to stay connected to the on-going workshop listings, subscribe to my clay/straw updates here: http://eepurl.com/u3AM1 If you would like to know about other things going on at the bioshelter, sign up for the monthly newsletter here: http://eepurl.com/llOcb
