Dear all,
I'm close to done with the cob-core building proposal; my
recommendation over SB, earthships, superadobe, bamboo huts etc. Please
feel free
to use it in anyway you may see fit if you're involved in relief work.
(And I'd appreciate suggestions for
improvements.)Â I'll gradually fill in the blanks in the budget, and
adjust if I've made any mistakes. Apart from that I'm off Haiti,
devoting my spring to more local issues...such as finalizing our straw
bale house and co-facilitating our internships.
This is the first introduction. Please enjoy the full text with
numerous links and illustrations on:
http://nbnetwork.org/nb/haiticob
Max Vittrup Jensen
Director, Events and Marketing
Natural Building Network
Important Disclaimer:
NBN is only a network. Our role in this plan has been to connect the
people with expertise in Natural Building, as well as advice an
effective approach in view of the local available local material,
economy, climate challenges and historical/cultural preferences of
Haitians. These parameters has eliminated a series of more exotic
building designs and techniques.
NBN does not have the funding and resources to proceed with
implementation of the plan, this is up to whoever wants to make use of
it. The plan is written in a pro-active tone by Max Vittrup Jensen,
(NBN board member), enabling it to be downloaded and used for
submission. Please do not interpret this as if the project is already
being implemented. It is important to emphasize that this is a plan
open for everyone to adapt and use, just make sure youâll contact the
relevant experts/sub contractors if you plan to include them in your
application.
ââââ00O00ââââ
EXECUTIVE SUMMARY
The aim of this project is to construct 4000 simple 4Ã5 meter
earthquake proven (9+) core-shelters out of bamboo re-enforced cob,
which residents easily can expand into family houses in the future. Our
emphasis is to work with future residents in design of their community
and structures: The process is based on training Haitian low-income
owner-builder teams, whoâll afterward be in charge of small mobile
commercial equipment, establishing local skills and enterprises. We
outline how three sustainable micro-businesses will be established as
part of the process.
A central element in organizing the community is a planning process
with future inhabitants, facilitated by experienced experts in
permaculture and urban design. This process will result in sustainable
neighborhood groups, which commits to jointly build a cluster of
dwellings; approximately 10-20 families per group. Key features of the
project will be enhancement of community facilities, rainwater
catchments, local waste-water treatment, and garden allotments.
We will then construct 10â x 16â Core homes that are earthquake proven
(9+). They will be built out of bamboo re-enforced cob (a mixture of
earth and straw), which residents easily can expand into family houses
in the future. Building together with both Haitians and international
volunteers, after an extensive training and guidance the foreign
builders will gradually withdraw to an advisory role, while repeating
the process for other groups. Our aim is to build structures which
residents easily can expand into family houses in the future. The
process is based on importing simple mobile earth and straw mixing
machines from Czech Republic, in order to expedite the building process.
Image of cob shed in Oregon; thicker walls and different roof. This is
without bamboo re-enforcement. Click here for quake test of such
structure
Addressing the Challenge: Cob Core Housing
Requirements
Thanks to extensive networking contacts and reports from Haiti relief
workers, along with the recommendation from the Haiti UN housing
Cluster, it has been concluded that addressing the housing shortage in
Haiti for the short-term means having a solution that meets the
following key requirements:
ÂÂÂ * Feeling of safety and comfort for inhabitants relative to seismic
activity
ÂÂÂ * Hurricane-ready
ÂÂÂ * Heat and flood management
ÂÂÂ * Durability
ÂÂÂ * High effectiveness in construction; utilize simple tools and
trained teams of assembly technicians working with untrained local labor
ÂÂÂ * Scalable production
ÂÂÂ * Low cost
ÂÂÂ * Low environmental impact
The cob-core units presents a solution to all of those challenges,
while predominantly utilizing local materials, and allowing for future
expansion of the units.
The use of Earthen construction allows for inclusion of minimum trained
labor of all genders and ages. It serve to regulate the interior heat,
and is freely available. Apparently Haitians are not very likely to
adapt to non-traditional shapes of housing, and hence our model is
proposed as a simple rectangle with a sloped roof: In due time other
rooms can be attached and the roof become a saddle roof. Earthen
construction is usual in Haiti as in the wattle and daub technique; Our
technique is somewhat the same, however further improved for seismic
activity and floods: We make a foundation out of old chunks of
concrete, secure plastic ties under the concrete which gets embedded in
the walls and are used to tie the light-weight bamboo roof construction
to the foundation. The four wall sections are made of split bamboo
woven into a 6 inch grid, and with diagonal split bamboo included, in
effect making a hexagon pattern in the grid. This techniques was
developed by J. Becker during relief work in Banda Aceh, Indonesia.
The cob machines are specially designed to fast and effectively mix
earth with long fibers, while remaining of a quite simple and sturdy
mobile design. The cob mixture is applied from both sides in about 4
inch thickness, while making sure that the long fibres (straw or local
grasses) are inserted through the holes of the bamboo grid into the
mixture on the other side. This way the cob core in effect becomes a
monolithic structure, which (once dry) is virtually non-destructible.
As bamboo is a grass, and the split pieces treated by boiling and kiln
dried, they are of no interest to termites.
Despite the high humidity the cob walls will dry relatively fast due to
breeze and the high average temperatures. Both the external sides of
the structure will get a lime plaster, which prevents damage from
driving rain. The resulting structure is more sturdy than the phase 2
structures proposed by the Haiti UN housing Cluster, hence resisting
hurricanes better, yet there is very limited possibility of the roof
or
walls doing any harm to the inhabitants, should an extreme magnitude
earthquake manage to damage the walls or roof.
The light weight concrete roof tiles represent a much lower degree of
embodied energy and cost, than the typical corrugated metal roofs, it
does not transfer heat to the interior in same way as metal, and it
dulls the sound of the torrential rainfall, while allowing for suitable
clean water to be captured and reused.