Back to the future

Catherine Wilson of CSK architects on creating a modern office space with a strong sense of its own history

The creation of the Howard de Walden Estate’s major new office development at 51-52 Welbeck Street began with what sounds like the quintessential Marylebone brief: start with two period buildings, constructed in slightly different eras and in markedly different architectural styles, and turn them into a single coherent office space without compromising their visual appeal.

“The Howard de Walden Estate wanted us to open the spaces right up, maximise the floor space and create bright, modern office accommodation, with efficient circulation,” says Catherine Wilson, an associate at CSK Architects—the firm employed by the Estate to transform these two neighbouring late-19th century houses, which had previously been filled with an assortment of residential and commercial units, into a large, modern office.

For Catherine’s practice, this kind of challenge is something of a specialism. “We particularly enjoy working in sensitive urban locations and our expertise is in the development of contemporary buildings in locations of historical significance,” she says. “We like to look at the history of a building and its wider setting, then determine what aspects are important to retain and what can be altered to provide a contemporary and fitting piece of architecture. We look to develop unique buildings which ‘belong’ to their place.”

Historic rooms
The simplest—and most brutal—option would have been to start from scratch with a modern construction behind the facades of the two houses, but both landlord and architect were keen to find a more nuanced solution. “Neither the Howard de Walden Estate nor CSK felt it appropriate to simply retain the façades and demolish the historic rooms within,” explains Catherine. “It was felt that this approach would create a space that did not relate in any way to its exterior, devoid of character and a sense of past.”

Instead, CSK came up with a plan that would meld together as much of the buildings’ existing fabric as possible, while extending to the rear to create a new façade overlooking Bentinck Mews. As is clearly apparent just from looking at their fenestration, 51 and 52 Welbeck Street have very different floor heights, so joining the buildings while retaining their historic structure meant creating a layout in which most of the floors are set across more than one level, punctuated with steps up or down.

The resulting development, while offering the wide open spaces demanded by modern businesses, has an unusual richness of texture. “I think the variation in floor heights helps to define different spaces, and also gives a character to the building, which I think sometimes can be lost when you have these vast open plan spaces,” says Catherine. “We were lucky in that there are very high floor-to-ceiling heights throughout, so even stepping up and down across the building you never end up with an area that feels too cramped.”

Contemporary detailing
Despite not being listed buildings, the Welbeck Street houses fell within the Harley Street Conservation Area, and hence had to be assessed by conservation officers before a planning application could be approved. “When we went round with them initially to review it, they picked up on some of the more interesting features, and those are the things that we’re interested in too—we want to keep them and enhance them,” says Catherine. “There were some really nice features—in particular, a coffered ceiling between the second and third floors.” These historic elements would be worked into the plan alongside the modern facilities and contemporary detailing.

One hidden architectural gem was missed during the initial survey, but was discovered when some of the modern interior walls were being demolished to open up the cellular layout. “During the strip-out, a number of elegant cast iron columns with fluted capitals were uncovered,” explains Catherine. “The original structural design had allowed for new steels to be inserted, but on uncovering this craftsmanship we decided to instead retain and reuse these columns, reminding the occupiers of the building’s past.”

The building’s centrepiece—both literally and figuratively—is a new concrete and cherry wood cantilevered staircase, the positioning of which became a defining element of the development. “Early iterations of the design looked at options to fully demolish the rear of the buildings. However, once it was agreed to position the stair centrally, the ideal place seemed to be within the existing rear bay window, which was retained as the stair enclosure. The old and new meet at this central point, and the new stair becomes the heart of the building, a communal space for all to enjoy.”

A painstaking operation
Creating this impressive structure was a painstaking operation. “The staircase went up in stages, flight by flight, which was a really interesting process to see. It was one of the last elements to go in, so it was really striking seeing it take shape.”

Similar care was taken in creating the metal and glass balustrades that decorate the new rear façade. “The balustrade detailing was the result of collaboration between CSK, The Howard de Walden Estate and Westminster City Council to deliver a design imbued with meaning,” says Catherine. “The design combines the motifs of the English rose and the Dutch tulip—a reminder of the Bentinck family, which belonged to both Dutch and British nobility, and the part the family played in the development of this part of London.”

The overall result is a building that has met that quintessential Marylebone brief with aplomb: a thoroughly contemporary space, designed to meet the demands of a commercial tenant for decades to come, but one that respects—and even enhances—its setting. “It is important to us to create a sense of delight in our architecture,” says Catherine. “We want to find a way to remind people in this hectic world to take the time to pause and connect with their surroundings.”