The Retrofit Revolution

In this climate of austerity, razing edifices to the ground and then building them from scratch can seem like hubristic folly, costly to both developers and the environment. So it was a welcome surprise when the Stirling Prize shortlist for the best new building in Britain—announced in July—included two reinvented structures among the six. In one case, a grim hulk of an office block from the early 1980s has been expanded and transformed into an elegant and hi-tech building by the firm Allford Hall Monaghan Morris (AHMM). In the other, the Royal Shakespeare Company’s headquarters in Stratford-upon-Avon has been thoroughly upgraded and re-fitted by Bennetts Associates Architects, with old and new arranged as a coherent and accessible whole. 

“There is no doubt that reworking existing buildings is a highly rewarding and responsible area of work for architects,” says Rab Bennetts, director and co-founder of Bennetts Associates, a London-based firm known for its strong sustainability ethos. Recycling old buildings is not only a matter of reducing environmental impact, he says, but also an opportunity to “retain memories, discover richer textures and use ‘found’ spaces that require innovative design solutions.” Reusing existing buildings can also act as a natural curb on emissions, Bennetts explains, because they are often more compact. 

His firm’s sensitive reworking of the Royal Shakespeare Company theatre, which contains elements from 1879, 1932 and 1985, has improved visitor circulation through the complex, and added improved facilities, such as cafés, a restaurant and a new viewing tower. Bennetts gutted and rebuilt the main auditorium to allow for new state-of-the-art acoustics. Yet the spirit of the old auditorium lives on in the foyer, which is now lined with well-worn floorboards salvaged from the old stage. “This famous theatre’s layers of history are exposed for everyone to see,” says Bennetts. 

Listed structures such as the RSC theatre are especially complicated to refurbish. AHMM did not have to deal with such hurdles in their work on the Angel Building in Islington (below). They ended up stripping and rebuilding the original concrete structure and then wrapping it with an energy-efficient double-glazed skin, framed with striking black aluminium. AHMM also extended the building on one side and added another floor, a café, some eye-catching rooftop terraces and a bright central atrium, which has become the building’s focal point. “Despite reusing the frame, the Angel is a new building that meets 21st-century standards by cleverly reinventing what was there,” says Simon Allford, a director at AHMM. Though he says the firm always tries to “work with the given context”, Allford is not keen to play the retrofitting evangelist. “We will always make new buildings and enjoy making new buildings,” he says firmly.

The Angel Building (pictured above) has been awarded an Excellent rating by BREEAM (the UK’s environmental assessment method for buildings) for its sustainable features, which include rainwater harvesting, biomass boilers and low-velocity water fittings. Nic Crawley, an associate at AHMM and the firm’s head of sustainability, says the new building uses half as much energy per unit area as an existing building of a similar size and function (according to current performance-benchmarking data). Also, by retaining approximately 33,000 tonnes of concrete he estimates that the building diverted about 40,000 square metres of concrete from landfill and prevented some 7,400 tonnes of carbon dioxide from being emitted. It is not until a building has been in use for years that its performance can properly be evaluated. Nevertheless, other tangible benefits include reduced time and risk on site, says Crawley, and less pollution from dust and transport. The client, Derwent London, a property developer, was also delighted to learn that by reusing the building’s core, the new building was 15% cheaper to create than it would have been had the previous structure been razed to the ground, according to estimates from Davis Langdon, a global construction consultant. 

Refits have made sense for decades, says Gene Kohn, co-founder and chairman of KPF, a global architecture firm. “There has always been a need to recycle, retrofit and refurbish existing buildings,” he adds, especially in historic city centres where structures often have cultural significance and are protected by listing status or planning guidelines. One of KPF’s first buildings, in 1978, involved creating the New York headquarters of the American Broadcasting Company from a 1905 Medical Battalion Armoury. In London in 2008 KPF completed an award-winning retrofit of a listed building for Unilever’s headquarters. This summer the firm unveiled its renovation of the Tour First in Paris, which involved adding 11 floors to the existing 39, making it the tallest building in the city. Though the new structure is 10% larger than the former tower, Kohn says its CO2 footprint has been halved. It was KPF’s second retrofit project in Paris’s La Défense business district. 

The goal is to create structures that have the “capacity to endure”, says Kohn. Architects have the responsibility to consider how their buildings might be reused in the future. Allford calls this a “case of long-life loose fit”, and says that “‘over-tailoring’ a building almost guarantees its redundancy”. Bennetts adds that because mechanical services, such as lifts, escalators and ventilation systems, have a relatively short lifespan, “simple, robust, passive buildings are best.” He says passive solutions, such as controlling how much sunlight can get into a building—by positioning windows in specific areas and varying their size or the material they are made from—are far more effective in reducing carbon-dioxide emissions than flashier measures such as wind turbines and photovoltaic panels. 

But perhaps the biggest drive towards retaining and recycling existing structures, rather than building from scratch, has come from a paradoxical source. “The more that regulations drive us towards energy efficiency in construction, the less we can actually achieve in terms of long-term CO2 savings,” explains Allford, because making a building designed to use less energy throughout its life may actually be carbon-intensive during the construction process. Fortunately, however, it would appear that a building does not have to be built from scratch to be energy-efficient, or, for that matter, completely new.    

Appeared on, September 2011

Photos by Peter Cook (RST) and Tim Soar (Angel Building)