FarmI wrote:
When I was a child, many decades ago, there were still a few
structures around on various farms that dated from the time of the
Depression and that were largely built out of a substance called
petrified hessian (hessian being what Americans call burlap).

To build these structures, a wooden frame would be constructed and
then hessian (burlap) would nailed to the frame whilst being
stretched tight. The hessian would then be painted with a mixture
made up of water, alum, cement, salt and lime. After about 3-5 coats
of this mix, the structure would be weather proof and the walls stiff
and surprisingly durable (given that even I can remember them and I
wasn't born till after WWII). It was a very cheap form of putting up
shelter and seems to have been used for poultry sheds and similar
structures.
I was wondering if this form of building was used in other parts of
the world but google is surprisingly quiet about it even if I do use
burlap as a search term instead of hessian. Has anyone come across
it before?

My grandfather was a plumber who worked on some of the first buildings in
Canberra, this would have been about 1915, and he took his new bride to live
in such a structure on site. He described it as hessian covered with layers
of whitewash but I think it was very likely the mix that you describe
because whitewash alone would not have stayed weather proof for long.

They lived in these "tents" because there were no houses to start with as
Canberra was built on a sheep station. My eldest aunt was born there and
grandma raised her in their tent while they were there. In winter the
temperature can drop to -8C and frosty, or you can get howling winds behind
rain at 6C. There only heating would have been wood fires but the tent would
have had almost no insulation ability. In summer it gets up to 43C,
obviously there was no aircon or domestic refrigeration for plumbers, my
guess is they would have been lucky to get ice for an ice box and that would
not have lasted long. They were tough in those days.

David