The AJ Specification Awards celebrate outstanding working relationships between architects, manufacturers and suppliers. The judging panels looked for entries that effectively demonstrated the design challenge and how a particular product or material was used to meet it, as well as evidence of how the architect worked with supplier or manufacturer to achieve a successful outcome.
The Central Building Lantern Refurbishment was winner of the Roofing and Drainage category:
In a time where there is a real interest in Brutalism, the judges felt there was something quite special about the way this unique building was being celebrated and protected beautifully here. They recognise the difficulties in conserving concrete - and felt this was a great example of it being successfully done.
Our challenge at Fitzwilliam College was how to refurbish and waterproof a complex shaped lantern, without visually altering or compromising the original design. This iconic pre-cast concrete scalloped lantern roof hovers over the brick elevations of the Central Building, allowing natural light to flood into the dining hall. The Central Building was the first piece of the masterplan which Sir Denys Lasdun (1914-2001) designed and completed for the College in 1963.
The curved shape of the lantern shells around the whole perimeter of the roof were a tricky area to resolve. Through discussion, it was determined that it would prove technically and aesthetically impractical to apply a sheet membrane to them.
Working closely as a team with the College, Roofing Contractors Cambridge (RCC) and Sika Sarnafil, we had many discussions and tests before we reached the pioneering approach to waterproof this complex shaped lantern.
The crucial element was getting the seals right with the different treatments. Through multiple tests as a team we ensured the most effective detailing was met between each product. The mastic joint between each concrete shell needed to be able to breath to allow movement, therefore the order of layering of treatments, number of coats and where each liquid treatment was applied or overlapped was carefully coordinated.
This iconic Brutalist gem of a building is now renewed and preserved for many years to come due to an innovative shell, fascia and roofing solution created through collaboration.