Used frequently in the 1960s and 70s, hyperbolic paraboloid roofs are smoothly curving in shape, but are formed from a series of straight pieces.
The copper-covered hyperbolic paraboloid roof of the Grade II* listed Commonwealth Institute exhibition building, originally constructed in 1962, weighs 2000 tonnes and measures some 55m x 55m – the same area as 15 tennis courts. It was strengthened and then supported on temporary supports, in its original position some 20m above ground. Then its walls and floors were demolished. Below the temporarily supported roof, new basement and floor structures were constructed, ultimately being built up to provide permanent support for the roof. The roof is very thin - so damage to it could be caused if movements in the temporary supports exceeded a tiny + or – 5mm.
Particularly impressive is the way in which the risks associated with supporting such a large fragile roof so high in the air were dealt with, by initial painstaking investigation, the design of strengthening and analysis of various scenarios, for example, the supports moving after initially being set up.
This audacious transformation of a listed building has created a fitting new home for the Design Museum and has delighted hundreds of thousands of visitors since its opening in November 2016.