be interlinked well. During earthquakes, storms
and tornadoes, the building needs to maintain
structural integrity, with the roof moving in
unity with the walls, and keeping them together.
If the roof becomes detached and starts to
move independently, this can accelerate the
collapse of a building. The structure needs to
be completed to a high standard. Roof rafters
and purlins need to be cut or cast to the correct
length, with little margin for error. Joints
between members need to be well made and
fit snugly together. Sufficient nails and screws
of the correct specification need to be used to
tie joints together so that they do not become a
point of weakness.
• Roof coverings of pitched roofs, whether sheets
or tiles, need to be tied securely to the frame.
Where walls are susceptible to damage by rain
or humidity, they also need to provide sufficient
overhang.
Applications
The following are examples of a few projects in
which the need for ensuring quality has been
recognised as important, and where steps have
been taken to implement quality control of all
houses and other buildings, as far as is practical.
Case 1: Builders Workshops after the Bandar Abbas Earthquake in Iran, 1977
An earthquake of magnitude 7.0 struck the city of Bandar Abbas and surrounding region in March 1977.
After the quake, a team of the NGO Development Workshop undertook a damage assessment of villages
in the area. It reported extensive damage, with many of the traditional flat-roofed buildings of mud brick
or stone rubble walls collapsing or undergoing serious damage. Only timber-framed buildings covered with
palm-frond matting, traditionally used as summer houses or animal shelters, remained substantially intact.
Overall, the poor quality of much of the building work in the area had been a significant cause for much
of the damage. Development Workshop decided to organise a course for builders to raise the standard of
construction and improve the earthquake resistance of buildings that they worked on. It was organised in
a location outside the earthquake-affected area, which allowed some builders from other seismically active
areas in Iran to participate too. The workshop lasted two months and covered:
• Assessing the problems and potential of traditional village building and modern building techniques;
• Understanding why and how earthquakes occur and how they affect buildings;
• Techniques and designs for strengthening buildings against earthquakes covering foundations, walls,
timber roofs and vault and dome roofs;
• Sharing knowledge and experimentation by the builders;
• Literacy classes, as many of the village builders were illiterate.
The focus of the workshop was on improving the skills of the builders to continue to build houses in the
traditional way but with more safety.
See: Afshar F. et al (1978) in the Practical Resources section.
8