50 50 IAN LIDDLE Engineer, Buro Happold
What is the best building of the past 50 years?
Foster's Willis Faber building at Ipswich. It's the landmark in glassclad buildings. Although there were those Mies sketches, no one had ever actually used glass totally for the skin of a real building.
What is the most significant innovation of the past 50 years?
Glass is an old material but it's the innovation of the past 50 years because of what people do with it:
coatings, fritting, solar control functions. And it's partly to do with the way people think about glass - it's now quite a good material to put on the outside of buildings even if you don't want to see through it, because it tends to stay clean and neat.
And the best building product?
Ethyl tetra fluoro ethylene foil.
When it was still thought of as a greenhouse material, we pioneered its use in 1990 in the atrium roof of RHWL's Chelsea and Westminster hospital. When you use it as a triple layer intelligent pneumatic structure, as at Festo's HQ in Stuttgart, you can print it and develop a high level of control over solar gain. It has a long way to go, not so much a substitute for windows - more an alternative to sky.
What innovation do you expect to see in the next 50 years?
High-tech will go higher and lowtech lower and simpler. Already a lot of building processes are getting lower tech - for example recycled, lower strength concrete which means thicker sections and more mass to dampen out temperature cycles. In the other direction, glass and foil and tension structure will continue to develop.
What won't change will be the fact that although people say the building and structure are responses to clients and their needs, it's really a competitive sport in which professional participants vie not to do what was done before.