Step 1
The challenge
'Most modern buildings in Kampala advertise their modernity by
using inappropriate imported cladding materials – a typical
favourite being blue glass and aluminium curtain walling imported
from Dubai.
'By contrast, the low-cost structures built by their owners in
the city outskirts use crude clay bricks made from the site and
burnt in wood or charcoal-fired kilns in situ.
'When designing Kampala’s new British High Commission, we
were determined to use locally appropriate materials and take advantage
of local skills and construction techniques, but upgrade them to
suit the requirements of a 21st century embassy building.
'The challenge was to develop terracotta products to use as walling,
windows surrounds, sun shading and paving that would develop existing
local skills, be practical, affordable and relate the building physically
and visually to the red lateritic soil on which it is built.
Step 2
The strategy
'We tested products from existing clayworks and ad-hoc brick kilns
around Kampala.
'What we wanted was not immediately obtainable, but we believed
that with the raw materials and local skills available, along with
ingenuity and a willingness to experiment, we could develop a palette
of materials for this project that may prove useful to others building
in Uganda.
'The first thing was to choose a main contractor that already had
a brickworks in operation (using local clay and burning coffee husks
to fire the kilns) and to develop a sequence of investigative design,
mock-ups, prototypes and sample testing into the overall design-and-build
programme for the project.
Step 3
Using terracotta
'Our aim was to use terracotta in different forms – paving,
walling, perforated screens, window surrounds (including lintels
and sills), sunshading louvers and roofing – for as much of
the exterior of the building as possible. All these had to be made
to work with the increasingly demanding security requirements of
a modern embassy, including bomb-blast proofing and security grilles.
Step 4
Mock-ups
'We first made card models to find forms that would work. We then
discussed these on site with the clay-workers in order to establish
the limits of mould casting, clay extrusion (and the cutting of
special steel extruding profiles) and the problems associated with
drying, shrinkage and distortion in the kiln. This also allowed
us to look at different textures and finishes to the clay products.
The builders then made full-scale timber mock-ups, in particular
of window surrounds and sunshades, followed by samples of the various
clay components.
Step 5
Testing & trying again
'We coordinated our trips to Uganda with the production of samples
from the kiln and then assessed the samples with the contractor.
Some elements changed shape too much in the drying process while
still “green”, others broke or exploded in the kiln
or came out cracked and deformed – and some were perfect and
beautiful.
'We also made accidental discoveries that informed the finished
result. For example, the bricks were laid rough side out, contrary
to normal Ugandan practice.
'Where prototypes were acceptable, they were built into sample
sections of the building (walls, windows, roofs), which were then
used to establish standards for the building itself and to explain
to the people on site our requirements. Where they didn’t
work, we adapted the design or abandoned that particular proposal
and started again.
Step 6
Building it
'Once the sample panels had been approved, the clayworks went into
production and we held our breath. The contractor produced 945,000
fired clay elements to construct this building, which is now complete.'
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