Gridshell Building, Weald and Downland Museum
Architect Edward Cullinan Architects
Engineer Buro Happold
Client Weald and Downland Open Air Museum, Singleton. Sponsors: Heritage Lottery Fund. Jerwood Foundation.
The Gridshell is essentially an industrial
building, a no-frills solution to the problem
posed by the museum, for a large tall open
space where the timbers and frames of
historic buildings can be laid out for
conservation and repair, before being erected
on the site of the museum. It is further used
for training courses in conservation.
The design objectives for the project were
for sustainable construction and energy
efficiency; an early decision was made that
daylighting should provide the principal means
of illumination. Artificial light was seen as a
necessary supplementary provision for
extended hours usage, or in extreme winter
conditions.
The primary use for the building required a
large tall open space free of obstruction for
the conservation work, with a smaller area for
use as a museum and storing of the museum’s
artefacts. Whilst the former required a high
level of energy efficient lighting, which was
interpreted as daylighting during the day, the
artefacts store would have intermittent use
and might therefore be met by artificial light
at all times.
The architect Edward Cullinan’s sketch
design illustrates the concept for the building,
showing the tall ‘conservation space’ above
ground level, well daylit from roof lighting,
whilst the ‘artefacts store’ is placed at a lower
level cut into the chalk hillside, artificially lit
when in use.
The lightweight Gridshell structure
designed by Buro Happold has been well
documented elsewhere, but the purpose of
this Case Study is to illustrate the nature and
quality of the daylighting, together with its
implication in terms of energy, for this is a
‘green’ building in which ‘sustainability’ and
energy efficiency is all a part of the ethos of
the museum itself.
Three important considerations were
apparent:- The roof should contain a high degree of
transparency. - The internal finishes should be light in
colour to improve contrast rendering. - A balance was to be found between the
need for a high level of daylight, and the
need to control solar gain.
The daylighting consists of continuous rows
of polycarbonate sheeting at high level, which
on the north side is ‘clear’, letting in
maximum daylight, and on the south side it
has a ‘bronze tint’ to reduce possible sun
glare. Looking up from inside the building the
effect of this change is visible but not
disturbing, and the impression at floor level is
of an even light, ideal for the needs of
conservation work. The consistency of the
northern light, complemented by the
variability of the southern light, formed the
final scheme proposal, the rooflights being
installed along the full length of the roof, to
ensure acceptable contrast, the result being an
even quality of daylighting, suitable for all
seasonable conditions.
The use of polycarbonate sheeting in place
of glass, whilst having an impact on reducing
the cost, was primarily because of its light
weight for erection purposes. There is a large
area of glazing and if any form of glass had
been specified its weight would have been a
factor.
For work after dark a sufficient level of
artificial light is available from a pattern of
downlights, visible in the photographs.
The building was completed in May 2002
and so far there has been no need for artificial
lighting to be used during the day, although
both conservation work and course tuition
have been in progress. The fact that no
electricity has been used for lighting the space
during the day is evidence of the building’s
energy efficiency, a strategy carried through
for the building’s heating and cooling.
By sinking the building into the slope of the
hillside it reduced the environmental impact
of the building on its surroundings, and whilst
it is a large building, one is not conscious of
this when visiting the site.
To sum up, the strategy for the building has
been proved to be successful; so much so that
the building won an RIBA architecture award,
and was shortlisted for the Stirling Prize.
The final result is an enclosed space with a
high level of daylight provision, estimated to
provide a Daylight Factor (DF) of 10 per cent.192 Daylighting: Natural Light in Architecture
Sketch section of the new building
Edward Cullinan