At Hofstraat House in Ghent, Belgium, there was no ‘back’ where an addition could be built, so the local firm Dierendonckblancke Architects found a solution by looking up. The resulting roof pavilion with terrace is reached by a spiral staircase.Credit…Filip Dujardin
In south London, a Victorian house has a new extension clad in black aluminum, with a distinctive three-fold roofline. The work has transformed a cold, dark area that the owners used very little into a bright, open-plan space that is now the hub of the home.
“Perhaps the best accolade we could give is even eighteen months from completion, the wow factor is still there,” wrote the owner, Alan Jones, in an email.
A short drive away is Battersea House, a terraced property that now has two extensions: a contemporary rooftop addition for a new master bedroom suite and an open-plan space downstairs. The latter stretches into the garden, and its cream brick contrasts with the postwar property’s dark painted exterior.
“The relationship of how we use the garden has totally changed,” said John Proctor, an architect and the owner of Battersea House, where he lives with his family. “A lot of these projects address the challenge of how a modern family wants to live.”
Mr. Proctor’s firm Proctor & Shaw, which specializes in projects like Battersea House and the nearby Victorian property, is among a number of practices elevating the extension beyond mere addition to something of an art form. Treating each project with the same care and creativity they would grant to a bigger venture, their approaches vary from the transitional to the transformational, and the range of benefits to owners can include both economic and environmental perks.
“Each one has its own story to tell,” Mr. Proctor said.
Like many extension projects, those at Battersea House were part of a larger-scale renovation, as was an extension to a California-style bungalow on the outskirts of Melbourne, in Australia.
“The owner didn’t need more space or big space,” said Chris Stanley, the co-director of a local architecture and interior design firm, Splinter Society. “It was really about redefining space and then reconnecting it to its garden to work better.”
Elwood House, a weatherboard bungalow badly in need of repair, had been occupied by the same owner, an actress and writer, for over 30 years. Her requirements were unusual.
“It wasn’t your standard brief of knock off the back of the house and put huge glass with flowing entertaining areas into the garden,” Mr. Stanley said. “It was more about creating smaller, intimate spaces that connected in different ways.” This meant that at different times of day, from season to season, he said, there were different things happening.
Among the intimate spaces the studio created was a new lounge room of around 30 square meters. It includes a library to house the owner’s many books and a large picture window that connects directly to the smaller of two added decks.
“The lounge connects to the garden in multiple ways,” said Mr. Stanley, “and because of where we positioned it, the addition allows the smaller private spaces behind it to have new connections to the garden through glass links.”
The room’s outer walls are covered in a cement render, picking up on the few areas where the material was already found in the bungalow and also on a connection to Japan, where the owner loves to travel.
“Traditionally a lot of the inspiration and references to California bungalows was of Japanese origin,” Mr. Stanley said. The builders used Arakabe, a traditional Japanese technique, and enhanced its textured appearance with a raked tool, “to give further relief in the surface to pick up on the light,” Mr. Stanley said.
While Proctor & Shaw’s modernist tendencies often lead to extensions that contrast with their parent home, particularly in parts of London where many buildings date to the Victorian era, Splinter Society says its personal preference is a blend between old and new.
“We don’t really do minimal or modern work, it normally picks up on cues or references from the old house and then reinterprets those in a modern way to create a bit of a continuity or homogeny,” Mr. Stanley said. “We usually think it’s important for there to be a link or a bit of a story in that connection, rather than place an alien addition on the back.”
At Hofstraat House, a neo-rococo building in Ghent, Belgium, there was no ‘back.’ Tasked with creating a reading room for a university professor with a lot of books, the local firm Dierendonckblancke Architects found a bold solution by looking up.
“We saw an opportunity because other than a small outdoor space with little sunlight on the ground floor, the owner had no outdoor space,” said Alexander Dierendonck, who leads the firm with Isabelle Blancke. “So we came up with a proposal to add a rooftop volume. The conditions were nice, with nice views of the city.”
The resulting roof pavilion, made from thick cross-laminated timber and including a small terrace, is reached by a spiral staircase in blue steel and is itself clad in wood painted bright red. “It was quite an intuitive choice,” Mr. Dierendonck said. “The city is quite gray. There is a lot of brick and stone in Belgium. The red color of the wood cabin makes it appear in the cityscape as a very small but present object.”
Persuading the client to go for it was quite easy — “The rooftop has immensely improved our quality of life,” said the owner, Yves Haeck, in an email — but persuading the city took a few meetings.
“It’s a real market within the historic cities to adapt the old houses to new conditions, often with very small spaces or with limited possibilities,” Mr. Dierendonck said. He believes every extension project should have its own identity, with a clear contrast between old and new. “It makes the city richer in my opinion,” he said.
A desire to enrich the surroundings with an extension that had a distinctive identity also shaped a project for a young engineer in the Ammersee lake district near Munich, in Germany. His add-on adjoins the existing family home, where the owner’s parents and a cousin live.
“We didn’t want the house to follow the architecture of the existing buildings but to follow the site’s topography,” said the architect, Fabian Wagner, the founder of Buero Wagner, “so that it is perceived as an independent building.”
Space constraints and municipality restrictions also played a role, since little space remained on which the owners would have been allowed to build, Mr. Wagner explained. “As Munich metropolitan region is subject to intensive pressure from settlement resulting in an explosive increase of land and property prices, the only possible and affordable expansion of living space was an extension of the existing building.”
Paul Cashin, an architect based in Winchester, in southern England, also said that “a constrained planning culture” is one of the main reasons for choosing extensions in favor of new construction in Britain. His firm, Paul Cashin Architects, recently remedied a series of extensions at a cottage dating to the 1830s in West Sussex, on the south coast.
“There were three or four extensions over the years that ruined the house further each time,” Mr. Cashin said. “Our brief was to get the labyrinth of rooms resolved.” Along with reconfiguring the layout to create better flow, Mr. Cashin and his team added 300 square feet and clad the back of the house in timber. “New extensions don’t need to shout about being new,” Mr. Cashin said. “As long as they are built of the now, style takes care of itself.”
In London, the annual “Don’t Move, Improve!” competition, in which a number of Proctor & Shaw’s projects have been recognized, celebrates the city’s most innovative extensions. Its name hopes to convey the advantages to choosing them over new homes.
Along with the opportunity to tailor them to personal requirements, extensions add interest, create a stronger connection between indoors and outdoors and allow owners to adapt their homes to modern lifestyles. Environmental benefits are also noted as being among the main benefits.
“For us, environmental is a given,” said Mr. Stanley of Australia’s Splinter Society. Clients commonly express their desire to minimize energy consumption, material use and landfill space, he said.
He finds identifying and revealing a house’s subtle history the more interesting challenge, however, seeing extension projects as a chance to create the “next story” in a property’s timeline. “You can’t build that,” he said. “That’s something you are given as a gift when you do a renovation.”