The insertion of new structures into original buildings is far trickier than a big new build on a greenfield site. 'Re-use and conservation are fundamental skills of the practice, ' says Alan Jones. Working with Corrigan + Soundy + Kiliaditi, AHA has inserted a new storey into New Schools, a colonnaded wing of Eton College built in the 1860s in exuberant Gothic style. The original pitched roof was replaced with a lightweight steel structure; the apex of its new curved roof is no higher than the original roofline.
The roof of another historic building, the Roundhouse in Camden, London, has also been under scrutiny. 'It's a magical cast- and wrought-iron roof structure, ' explains Jones. 'Fine and delicate to a degree that even today's computers would struggle to calculate.' As part of the refurbishment with John McAslan + Partners, a new 'top hat' will be placed over the structure to improve acoustics and support lighting gantries.
AHA has worked with Blencowe Levine Associates on a new rear extension to a 19thcentury semi-detached house. It was substantially opened up with clear-span steelwork at roof level and internally, including the removal of the entire rear wall over two stories.
The new extension has an exposed steel frame of minimum dimensions designed to resist the torsion forces of the all-glass garden elevation. The project creates new open living space in direct contact with a large mature garden.
Top: this ingenious folding bridge by Thomas Heatherwick, the latest of several collaborations with AHA, consists of hinged trapezoidal segments which are fitted with hydraulic rams, allowing them to be pushed up in sequence. Middle left: a steel and acrylic sculpture, designed by Diane Edmunds and David MacIlwayne, hangs from the atrium of a new office building in Bristol.AHA worked with the sculptor to create a stable suspended form.Middle right: this staircase is a one-off design in tubular stainless steel with machined green oak treads, in a listed timber-frame building in Maidenhead.
Bottom: Blencowe Levine Associates'rear extension to a 19th-century house