How the sustainably-minded brains behind the London Eye rescued a Warwick Avenue townhouse from the brink of collapse
Marks Barfield are known for their public projects, but behind the scenes they've been cultivating a reputation for outstanding residential renovations with sustainability front and centre.
It is a truth universally acknowledged that a person doesn’t realise how inconvenient something is until it’s done better. Nowhere is this more apparent than in our homes. The key that needs jimmying, the door that requires a knack to close, the drawer that demands coaxing: such irritations soon become unfelt. Until, that is, you have a house that works.
The owners of this Victorian house on Warwick Avenue in west London know this better than most. When they bought it, in 1993, the house — spacious, with a beautiful garden and access to an enormous shared private square beyond — made perfect sense. There was enough room for their growing family and fewer stairs than the Hampstead home they were leaving behind. Yes, there were quirks — the windows were leaky, the configuration was a little strange, the spare bedroom was too big and the master had no en-suite — but these were nothing a bit of patience couldn’t counter. And, besides, the handsome property had charm and character.
However, in the late 2010s, a damp problem took hold, creeping ominously through the lower-ground level. The couple, both lawyers, knew the basement was in need of serious attention, ‘and we also knew we weren’t going to put our 25-year-old kitchen back in,’ one of them recalls. They enlisted Marks Barfield, a Clapham-based practice, who are best known for their public projects — the London Eye, Cambridge Central Mosque, Brighton’s i360, the Treetop Walkway at Royal Botanic Gardens, Kew — but behind the scenes have been quietly building a reputation for their low-waste, regenerative approach to residential ones.
‘The original plan was focused largely on the basement,’ says Julia Barfield, co-founder and director of Marks Barfield, ‘incorporating a study, a mudroom, a gym, some wine storage and a new kitchen extension.’ Receptive to Marks Barfield’s inherent ‘greenness’, the couple also began thinking about installing air-source heat pumps to replace the tiny, cranky combi boiler, but as the practice began examining the building’s performance it became clear that simply replacing the heat source wouldn’t fix the heating problem. As one of the owners puts it, ‘there was absolutely no point in doing half a house.’
Details of the ground floor bannister.
Brickwork was left exposed in the lower ground floor boot room.
Before long, Marks Barfield had engineered an extensive top-to-bottom retrofit that not only addressed the damp ingress, but completely reshaped the building’s thermal performance — something the house was in desperate need of because it had little to no insulation. Under the guidance of practice director Ian Crockford, the team started to install breathable, wood-fibre insulation and lime plaster, fossil-fuel-free air-source heat pumps and mechanical ventilation systems, setting their sights on creating a home that performed to Passivhaus standards.
The course of renovations never did run smooth and as they began to strip things back to the brickwork, the architects came across oddity after oddity, and challenge after challenge. At some point in the house’s history, someone had decided to chop chunks out of the roof purlins, a choice which, combined with the four water tanks, each weighing about three tons and dating to the time the house had been cleaved into flats, meanest that the external walls had started to bow by 60cm. Meanwhile, a dormer window in the attic was discovered to have no lintel and therefore supporting the entire weight of the roof.
The home's extension houses the new kitchen.
The house is Grade II-listed and sits inside a conservation area, so planning alone took six months, and Marks Barfield were required not just to reinforce the roof, but retain as much as possible of the existing fabric. As an outfit interested in circular building practices, this was, mercifully, preferable. In fact, throughout the house, the architects tried to reuse materials wherever possible, while also designing for deconstruction, ensuring that — as Julia says — ‘anything we’ve done can be taken apart, the materials reused by someone else in the future.’
Underneath the basement extension, Marks Barfield installed stainless-steel screw piles, upon which sits a ground beam made from repurposed rolled steel joists. The window frames and 99% of the brickwork were reused; the extension’s douglas fir exterior, with its subtle psychedelic grain, came from an old carton factory in Devon. In a neat twist, it originates from the same part of west Canada as one of the owners, likely arriving in the UK about 50 years before her.
Where the architects weren’t able to reuse or recycle, they opted for low-carbon solutions, such as a green roof and heritage-friendly, Fineo sash windows, which use a vacuum between the panes instead of glass to achieve thermal insulation that’s as effective as triple glazing. They also operated a ‘host and donor system’, giving steel reclaimed from this house to another one under the care of Marks Barfield in Stockwell.
These choices reflect Julia’s desire to be ‘a good ancestor’, a term borrowed from the title of Roman Krznaric’s 2020 book about ways in which long-term thinking can benefit future generations. Conscious that the building industry is responsible for 62% of the UK’s waste, she and her practice endeavour to work as responsibly as possible. It’s admirable, but it’s also plain common sense (Julia once saved a client £1.65 million by reusing materials). ‘The driver for us is the planet,’ she says, ‘but it’s enormously reassuring that our principles don’t get in the way for our clients.’
Back in Warwick Avenue, common sense has prevailed in a way it definitely didn’t before. By slicing up the enormous spare room and removing a strange, cupboard-like bathroom that once occupied a nearby half-landing, Marks Barfield has created a spacious ensuite for their clients. A lot of the work — including the insulation and plastering — is invisible, but no less important. While working on the upper floors, Ian noticed that the joists had been hacked apart to make way for plumbing and reinforced them. ‘It’s a miracle the bathtubs didn’t fall through the ceiling,’ he says. However, where the practice’s handiwork is on show (notably in the basement, which is now a cool and airy enclave with enough space for work, fun and family life) it is undeniably pleasing: comfortable, beautiful, logical.
The logic that Marks Barfield has imposed on this house is what makes it special. ‘We could have stayed here for another 30 years,’ says one of the owners, ‘and it would have been fine. But now it is enjoyable — cool in summer, warm in winter. It’s how a house should be.’
The other one tells me about a window that illuminates the junction between the ground and first floors: large, arched and ‘almost chapel-like’, she says. ‘We lived for decades with its strange mismatch of glass panes. Some were frosted, some were patterned, some were plain.’ Now restored to its original design, the window is a thing of unintrusive, low-key beauty. ‘I didn’t realise how nonsensical it was.’ She is talking about the window, of course, though the observation seems to reach much further.
Visit the Marks Barfield website for more information.
