Heinz Isler's Infinite Spectrum: Formfinding in Design

Heinz Isler with Copeland
Associates and Haus + Herd,
Tennis halls, Norfolk Health &
Racquets Club, Norwich, UK, 1987
opposite bottom and right: Of Isler’s
free-form shells derived from a hanging
membrane, the most common are
the swimming pool and tennis/sports
halls. The upturned edges provide
stiffening for the adjacent shells, which
spring directly from the ground. Due
to the quality of the concrete and
its permanent compressive state, no
waterproofi ng is required.
air museum at Dübendorf (1987) and his oftrepeated
tennis hall and swimming pool shells. 3
It is unfortunate that, unlike the ‘bubble’ shells
created using the infl ated membrane method,
which were used repeatedly for industrial shells
of up to 55-metre (180.4-foot) spans, those
generated from the hanging membrane were
generally ‘one-offs’ or built in limited numbers due
to the cost and complexity of the formwork. The
exceptions were the tennis halls and swimming
pools where clever adaptation allowed slightly
different-sized shells to be cast using virtually the
same formwork.
So why have Isler’s methods not been copied?
One reason may be because, although apparently
simple, the processes are complex and require
extreme precision – a trait that Isler had in
profusion. This complexity is especially true for the
hanging membranes, where he did not start with
a fl at plane between supports but deliberately
chose a membrane surface of greater area with
excess material at the perimeter, permitting
initial sag. Consequently, there is, literally, an
infi nite number of alternatives and he needed to
make and test suffi cient examples to enable him
to choose (or compromise) between the most
economic in use of material, most structurally
effi cient and most aesthetically graceful. This was
his skill as a designer and structural artist.
During conversations in March 2003, at the
his studio in Lyssachschachen, with the author
and Ekkehard Ramm, Isler refl ected on what
would happen to his unique approach to the
form-fi nding of shells once he was gone – given
that, at the time, his offi ce employed just one
person and he had no successor:
What is happening when I fall in the
woods and I do not rise anymore?
Then it is gone. No it’s not gone … the
spiritual background of it (whether it
be called the law, or the appreciation,
or the understanding of the law) and
the application of the law, that will
go on. That is science. ... there are
people who will be able to catch that,
to understand that or to rediscover it in
their own way. 4
He was not wrong. For several years Mark
West, from the University of Manitoba,
inspired by Isler’s work, has been using tensile
membranes as formwork for effi cient freeform
structural elements as diverse as beams,
columns, fl oor panels and cladding panels.
More recently, although the construction
material is different, the Mapungubwe
Interpretation Centre in South Africa, by
Peter Rich Architects, the World Architecture
Festival’s Building of the Year 2009,
incorporates masonry vaults highly reminiscent
of Isler’s tennis halls. 1
Notes
1. Heinz Isler, ‘New Shapes for Shells’, Bulletin of the
IASS, No 8, Paper C3, 1961.
2. Heinz Isler, Discussion (fi nal paragraph): ‘New Shapes
for Shells’, Bulletin of the IASS, op cit.
3. See John Chilton, Heinz Isler, Thomas Telford (London),
2000, pp 91–119.
4. Heinz Isler, recorded conversation with John Chilton
and Ekkehard Ramm at Buro Isler, Lyssachschachen, near
Burgdorf, Switzerland, 18 March 2003 (unpublished).
Text © 2010 John Wiley & Sons Ltd. Images: pp 64-5, 66(t&b), 67,
68(l&tr), 69-71© John Chilton; p 66(tr) © IASS Journal; p 68(br) ©
Peter Rich, photo Robert Rich
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