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< prev - next > Construction Earth construction woodless construction 3 (Printable PDF)
Woodless construction: change and adaptation to local needs
Practical Action
Flat roofs on vaults and domes
When introduced to Mali, woodless construction aroused strong local interest in the face of
increasing difficulty in finding organic materials or the money to pay for non-local alternatives. Many
people nevertheless wanted flat roofs, where they could sit and sleep outside during the hot season.
As a result in subsequent training, the construction of flat roof terraces with vaults and domes was
demonstrated, using secondary vaults and domes to bridge over the "valleys" between the main roof
vaults or domes. The much smaller valleys in the roof that remain are filled in with earth. Combined
with the use of eccentric domes and vaults these can further reduce the need for in fill in the roof,
an otherwise expensive item.
Reduced wall thickness
Woodless construction is mainly about changing the way that people build roofs, but how much
material goes into walls is also a concern. In northern Niger, the traditional branch and straw shelter
- the tatagham shelter built and used by women in nomad settlements - was also becoming hard to
build because of difficulty in obtaining materials. A 200 mm thin walled domed structure was
proposed as a replacement. Similar reductions in wall thickness for rectangular structures has also
been introduced using alcoves, which - without reducing the strength of the wall - reduce the
number of bricks needed and provide useful space.
Replacing existing timber roofs with vaults and domes
In many parts of the Sahel, existing earth buildings already have thick masonry walls. As well as
training for constructing new buildings with woodless construction, the Woodless Construction
Programme has also demonstrated the potential for re-roofing existing wood roofed buildings with
vaults and domes, provided of course that the walls are sufficiently strong. One particularly
successful example of this was re-building the roof of an existing mosque, the wooden roof of which
had rotted; this proved a highly popular and "visible" example to the local population.
Technical changes are making Woodless Construction building easier and more attractive to clients.
But just as important is the impact that these changes are having on how local masons and clients
are taking decisions into their own hands: laying out bricks to measure the size of a new building on
the ground, and then "re-arranging" rooms to suit the client's wishes; or trying out different vault
positions by drawing full size on the wall. All increase opportunities for masons to find viable
solutions to local clients' needs unaided.
The promotion of Woodless Construction in Burkina Faso, Mali and Niger won the World
Habitat Award in 1998
Selected references
Woodless Construction 1: An Overview J. Norton
Woodless Construction 2: The Training of Trainers and Builders J. Norton
Building with Earth, 2nd Ed., J. Norton, Practical Action Publishing, 1997 (Order online at Practical
Action Publishing)
Woodless Construction Unstabilised earth brick vault and dome roofing without formwork. J.
Norton, Lund University Centre for Habitat Studies, Vol 9,N°2, 1997 (Download at
Mud as a Mortar, Practical Action, Technical Brief
The Construction of the Timberless House Model, Practical Action Sudan, Technical Brief
Mud Plasters and Renders, Practical Action Sudan, Technical Brief