walls which are highly insulated. These ensure a high
level of comfort in summer and winter. Because the community don't use
it continuously its ability to be comfortable even after a period
where it is empty either in summer or winter is very important.
Building with volunteers means very low cost. The soil
was sourced at site, bales were bought from a neighbouring farm.
Working with volunteer labour is a bit unpredictable, how many, for
how long? Since the community couldn't answer these questions
using commercial formwork, hiring it in, was out of the question.
Instead we advised on how many used scaffold planks to buy. Once this
was done we made up formwork which could remain in place if need be
for months, as the total cost was around £300 for the boards. However
the formwork was 20m long, easily enough to keep up to 30 people busy
at any one time.
The technical aspects of tying straw bale to rammed
earth physically, ensuring no gaps between the mass and the
insulation, was done in two ways, both of which worked well. one was a
simple wire tie through the walls where it was to be plastered over.
The other method built strips of mesh into the wall which formed a
horizontal tie into the bales.
One thing the community couldn't control was a planning
restriction which meant the building had to be on 1.2m stilts against
future flooding. So a contractor built a raised
platform and erected a timber structure on top with a roof. This meant
the community could finish the rest of the build themselves in their
own time.
The
community had planned to use as much material from site
as they could. This started with a small group going to a range of
different workshops to try to understand the different technologies they wanted to try, rammed earth, adobe
and straw bale being the big three wall building techniques.
Because
the roof was built before the walls the rammed earth could not be
built to roof height. Adobe blocks were made to fill the gap between
the top on the rammed earth and the under side of the roof, a very
happy use of the two complimentary building systems.
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