The
Greenhouse
This project was worked on by many different people. It began in July.
1996, as part of a course on Natural Building offered through the Faculty
of Architecture, TUNS and led by Jean D'Aragon and Straw Bale Projects.
Foundation
We used an experimental earth bag system which evolved from local
traditional building knowledge, and work done by Nader Kahlili and Joseph
Kennedy in California in the l980's. This system has great potential as an
affordable, sustainable foundation.
A drainage trench four feet wide and filled with gravel takes water
away the site on a grade from one foot to four inches. The principal is
that, if water can be directed away from the foundation then there will be
nothing to precipitate the usual frost heave.
The site was leveled, disturbing the ground as little as possible.
Recycled polypropylene feed sacks were filled with gravel and soil. These
were secured closed by stitching them with nails. The bags were laid out
in a running bond, then tied together with nylon strapping which was
tightly cinched down.
This foundation is extremely solid. It uses local and recycled
materials as well as less embodied energy than conventional systems.
Walls
The more areas where straw can be used the warmer and the more
economical the building will be. The vaulted greenhouse is an experiment
in the use of straw as a roofing system Using traditional bent wood arches
of green larch a strong and beautiful base for roofing was created.
The walls were covered in a cement stucco. The windows were orientated
to solar south and slightly sloped for maximum solar gain.
Roof
An inferior quality tarp was used to sheath the roof, which has proved
to be its downfall. This tarp was painted with roofing pitch, but the
summer sun caused the tar to flow and exposed weak areas in the tarp which
allowed water in. This was not detected in time and has caused the burlap
to rot out. Another lesson clearly learned, in the living laboratory at
Ship Harbour.