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Alexander admits that this pattern is the most
contentious of them all. A roof carries with it cultural heritage and social
expectations which he tries to avoid by a fundamental analysis of the roof
while still meeting the requirements of the related patterns such
as No.117,
Sheltering Roof.
The criteria he identifies are that the roof: satisfies the
psychological sense of safety; provides a lived in space rather
than just a hat above the living spaces; give an indication of the social layout of the building;
should not be a complicated contrived structure; should avoid bending requiring tensile materials,
and should shed rain and snow suitable for its climate. Taking
other patterns in to consideration then collectively these exclude the flat
roof, pitched roof and geodesic domes (ironically a popular structure many
eco-villages like to play with). |
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Alexander notes (from 1977 when his book was
published) that, "...we believe these tension materials [wood,
steel] will become more and more rare". The scarcity of tensioning
materials like wood is exactly why the non-profit organisation
La Voute
Nubienne helps communities in Africa to build the roof vault
solution Alexander proposed 35 years earlier. Their work in
sub-Saharan Africa is helping to replace the traditional use of timber for |
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roofing. Population growth in the region, together with increasing
desertification and regression of forested areas, means that the
traditional use of timber is no longer feasible. You can see
more of their work, as shown above, on their English facebook page
Association la Voute Nubienne |
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The picture far left is Sky House, one of the
beautiful 'relaxed' homes built by the natural builder
SunRay Kelly
in the USA. The roof is a good example of pattern No.116 Cascade of
Roofs and
No.117 Sheltering Roof, but a look inside the attic bedroom
(left) demonstrates pattern No.220. It shows the convex curve that
Alexander prescribes but achieved here with natural roundwood
timbers that retain much more strength than milled timbers.
Here's a short film about SunRay's building philosophy which
starts with a view of Sky House and the window of this bedroom.
SunRay is one of several natural builders using roundwood timber
methods. In the UK
Ben Law developed efficient building methods reviving the
cruck frame using green roundwood timbers. |
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