How The Portman Estate’s new 1-9 Seymour Street development came to be designed for a broad mix of uses while meeting a heady cocktail of sustainability standards 

Words: Viel Richardson
Images: Grant Smith

“We were asked to undertake a project on the site of the old Marylebone police station. The building had a forbidding presence,” says Eric Parry, founder and principal of Eric Parry Architects. “The top floor was like something out of a gothic novel and housed a shooting gallery. On the street, there was a mouse hole of an entrance. It wasn’t an overly inviting building—it did not draw you in. In fact, it did quite the opposite.” Eric’s first impression of the 1-9 Seymour Street site was, it’s fair to say, not promising. Standing a stone’s throw from one of London’s great squares, he was faced with a dull, lifeless section of Marylebone not at all reflective of the vibrant area surrounding it.

“From the beginning, the Estate had a clear ambition for the project to redevelop the site: they wanted grade A offices, high-quality homes and a community use aspect, which was to be centred on education. Just as importantly, they wanted to activate the street frontage on both sides, so the building also includes restaurant facilities,” Eric continues. “Their ambition was wonderful to hear. They wanted to create a completely contemporary building that would become a classic over time; a building that works within its context, but at the same time has a freshness about it.”

Michael Jones was The Portman Estate project director whose job it was to deliver the project. “The Seymour Street development is central to the area and gave us the opportunity to create a game-changing development in the heart of the Estate,” he explains. “We wanted this development to set the standards for developments going forward, with great design, sustainability and longevity being key factors. We wanted to ensure, through the design and construction, that the building was flexible enough to continue to meet the occupiers’ needs for the long term.”


Relationship between spaces
One of the most important requirements was the creation of intermediate office spaces suitable for medium-sized businesses—something the Estate was previously lacking in the area. The new development will also provide facilities for a restaurant, homes, and community use—a complex mix that required real skill to achieve. One of the key reasons for calling in Eric Parry Architects was the partnership’s reputation for creating well-designed, high-quality mixed-use buildings in urban environments. “The challenge when designing a mixed-use building is the coexistence of very different spaces, with very different requirements. You have to be very judicious about the relationship between the spaces,” Eric explains. “For example, you must be careful about the window layout to ensure you provide the different areas with the lighting and views they need, while staying true to the needs of the building as a piece of architecture. To achieve all this, we have used quite simple materials, but in an interesting and innovative way.”

The development has two distinct elevations: one on Seymour Street, the other on Bryanston Street. The streets have very different characters, so the architects chose a different design aesthetic for each. For Seymour Street, this meant a crisp, well-tailored response that built on the tradition of the street’s Georgian terraces. “The dark brick we used on the front is mellow, handmade and very nicely finished,” the architect tells me. “The window surrounds are in vitreous enamel, so from the inside you are looking through reflective white flanks and from the street, instead of a sombre facade in brickwork, you get these lovely flashes of light.” Meanwhile, the Bryanston frontage has a more contemporary, art deco feel. “The windows pop out, breaking the plane of the building and giving the residential units views up and down, as well as across, the street,” he continues. “There is a wonderful aspect as you look westward on Bryanston Street, with the church spires as well as the more modern architecture.”

One of the designs that worked out particularly well in Eric’s opinion is the cornice on the north-facing Seymour Street facade. “I had this idea that on the north side of the building, if we inserted glass lenses in the overhang, you would get light reflecting back onto the frontage instead of it being in shadow. I have to say, it has worked spectacularly—it is rather beautiful. It has really helped the building activate what was a drab section of the street.”


The sustainability side
Having entrusted the architectural integrity of the development to the hands of Eric and his team, Michael took a hard look at the sustainability side of the project. He initially set the target of achieving a BREEAM rating of ‘excellent’. BREEAM, which stands for Building Research Establishment Environmental Assessment Method, is a highly respected set of independently assessed criteria for rating and certifying the sustainability of commercial buildings. The team also decided to go for Eco Homes level four, the government-sponsored residential equivalent of the BREEAM certification. “Even though the government has now scrapped the Eco Homes scheme, it is a standard we continued to work to, as we believe in what it was trying to achieve,” Michael tells me. However, while working on the BREEAM aspects of the design, Michael’s team realised that with a little extra effort they could go for an ‘outstanding’ accreditation: the highest rating the code recognises.

“In order to achieve outstanding BREEAM certification, the project has to demonstrate some innovative elements of design. Our innovation was to apply a system called ‘whole life carbon costing’.” As the name suggests, this takes into account how much carbon is used from construction, to the end of the building’s life, including raw material acquisition, processing, transportation, operation of the building, its demolition, and waste management. “It is a speciality in itself, and very complex,” Michael says with a wry grin. “The idea is, through the design of the building, to challenge processes and encourage ideas that reduce its carbon footprint, and incorporate them into the developer’s procurement systems and the wider design team’s thought processes.”

Michael goes on to explain that tools and systems exist that allow you to select materials based on the size of their carbon footprint. “An example is when you are procuring the steel frame contractor. As well as their technical capability and competitiveness, they were asked how much of their steel could contain recycled materials. They were also given the opportunity to put forward their own ideas. By repeating this for each specialist area you can accumulate significant carbon savings.”

The Portman Estate is the key stakeholder in the area, and as such Michael believes it to have a responsibility for setting building standards. He also wanted to show that you can develop properties for rental and sale that are commercially viable, but also meet these high sustainability standards. “You do not need to compromise on your principles,” he says with feeling.


Ambitious targets
More proof of this is in the decision to build some of the residential apartments to the Lifetime Homes standard, in addition to Eco Homes level four. This involves building adaptability into the apartments, allowing for changes to be made to meet the needs of owners or occupiers as their lives progress. “It is not a case of including everything initially, but rather ensuring that the structure is in place to make adaptations easier if they are needed in the future,” Michael explains. “There may sometimes be a perception that ‘lifetime homes’ are of a lower quality, but we wanted to show that you could build high-quality homes which meet the specification.”

A huge amount of thought has gone into the planning of 1-9 Seymour Street—the Estate’s largest solo development project to date. “A great many talented people have worked very hard throughout this project. We set ourselves ambitious targets, but these reflect the confidence we have in this part of London,” Michael says with a smile. “I think we have produced a building that delivers the needs of the neighbourhood both in terms of use, and architectural quality.”

Eric is also happy with what has been achieved. Among the things that pleases him most is the working relationship the practice has developed with the Estate. “One of the lovely things about this particular client is that they think long-term. The project was not about short-term profit; it is a development rooted in the long-term interests of the area”—something which, in today’s London, is not always the case.

“I am going to get a real buzz walking down Bryanston Street and Seymour Street for years to come—especially when I see that twinkle from the cornice,” says Eric. “Putting up a building in this wonderful area that is hopefully going to last for several hundred years is an incredible privilege. I shall enjoy making my way to this part of the West End as long as I am able.”