of building inspection, with inspectors checking
quality and ultimately issuing a Certificate of
Completion or similar document that proves the
satisfactory completion of houses and before
owners are allowed to occupy them (or rent them
out). This is an independent system, and if it has
not suffered itself too much from the disaster,
and has the capacity to deal with an upsurge in
inspections, it could prove the best choice. If it
cannot take on the task, then other professional
institutions should be considered, e.g. housing
authorities, research institutes, universities, or
check consultants (see case 4 in the Applications
section). Inspection would normally be required
at least upon completing the foundations (at the
plinth level), upon completion of the walls or
structural frame, upon completion of the roof,
upon completion of any services like electricity or
sanitation, and upon completion of doors, windows
and finishes, but it could vary somewhat according
to the housing designs. Inspection should pay
particular attention to structural safety. After each
inspection, an inspector can sign off the respective
component as satisfactory. On doing so, inhabitants
are entitled to the next cash instalment to continue
with the building process.
What needs particular attention in
construction?
It is beyond the scope of this Tool to run through
the many components of a house and the many
technologies that are used to build those worldwide,
to advise on their quality and particularly their
resistance to a range of natural hazards. Some
of the practical resources provided at the end of
this tool provide more detailed guidance on that,
in particular Coburn and others (1995). However,
we know from damage assessments after many
disasters that some mistakes or unsatisfactory
types of work are repeatedly made by unqualified
builders. The most important are summarised
below:
• Foundations need to be sufficiently deep,
massive and strong enough to resist damage by
floods and moderate earthquakes. Building on
unstable ground or steep slopes is best avoided,
as it would require expensive foundations to
make a building safe. Building on slopes above
10% is not recommended. Great care needs
to be taken when starting to build walls above
the plinth layer, as this may become a point of
weakness.
• Structural frames should be avoided unless
local builders have good knowledge of
frame construction. Poorly constructed and
inadequately jointed frames of reinforced
concrete, steel or timber can put inhabitants at
high risk. On the other hand, if frames are well
built and compatible infill or cladding materials
Care needs to be taken to finish the foundations with a perfectly
horizontal layer, to provide a good base for the walls
used, this can confer a high level of safety.
See the description of dhajji construction in
Pakistan, by M. Stephenson in the resources
section, for a good example of timber-frame
construction.
• Masonry walls need to be built with a proper
bond in all directions. Walls must be level
(horizontally) and plumb (vertically). Check
for this using a spirit level and plumb line. If
walls are built with distortion, even if it is not
visible to the naked eye, this may be a source of
weakness.
• Doors and windows need to be evenly
distributed, and not placed too closely to
corners or intersections of walls, as this weakens
the walls’ resistance to earthquakes. Lintels
above those openings need to be of sufficient
strength and length.
• Roof structures need to be anchored well to a
wall plate or structural frame; they also need to
This roof collapsed during an earthquake in Moquegua, Peru,
because of poor anchoring to the walls
7