Building Block: Roedean frames the past

As a rule, additions to historic school buildings favour pastiche. School communities tend to be conservative and resistant to change, and often imitation is the simplest, least controversial way to integrate old and new, if not always imaginative or best.

Roedean School's newly launched Rene and Fred England Centre for Mathematics Excellence boldly juxtaposes modern and historical architecture. The most visible part of it is a glass box or bridge classroom floating between two of the school's heritage buildings dating back to the first half of the last century. (The oldest dates back to 1903 and was designed by Herbert Baker, while a number of additions were made by his partner, Francis Fleming.)

Mary Williams, Roedean's headmistress, explained that the school wanted to make a statement. The aim of the centre is to address both "national imperatives in education" - the low standard of maths and the "issue of gender", or the tendency among girls to underperform in the subject.

"This facility could not be ordinary or mundane," she said.

The school commissioned Sarah Calburn Architects to design the centre. Calburn is a second-generation Roedean old girl with a daughter at the school. Her relationship with the buildings is intimate; she said that growing up among them helped form her spatial imagination. "And because I was at school here, I knew all the short cuts," she said.

Over the decades, various additions had reconfigured the school to the point where the entrance had become a circuitous route down stairs and up alleyways, past the kitchen and dustbins. The relationship between the buildings was awkward and many of their heritage features had become obscured by what Williams calls ''ghastly add-ons".

Calburn immediately saw that a modern glass structure would allow her to almost invisibly create a nexus - ''a system of linkages" between the buildings - while also allowing her ''to reframe what was here": to create views of the famously beautiful gardens and draw attention to aspects of the original architecture.

Calburn was gratified at the centre's launch to overhear old girls vividly recalling details of the altered dormitories from their school days: the memory of the old spaces still fresh within the new.

As Flo Bird of the Johannesburg Heritage Foundation observed, while it symbolises maths as a new frontier, it retains a sense of rootedness, subtly framing the past.