The CircularBuild 2026 retrofit shift was laid bare in data at this year’s event in London, where speakers charted a structural reorientation in commercial development away from new build and towards reuse, adaptive retrofit and circular materials thinking. Held at Convene at 155 Bishopsgate, the one-day conference drew hundreds of built environment professionals for keynotes, case studies and pointed arguments about what the industry should do next.
Refurbishment now dominates London office starts
The headline market data set the tone for the day. Hurst told attendees that last year in the City of London ‘almost twice as much office floorspace was starting on site through reuse as through new build.’ That observation is consistent with the longer trajectory captured by Deloitte’s London Office Crane Survey: in 2021, refurbishment accounted for around 54 per cent of new office-development starts across central London by floorspace, against 46 per cent for new build. By 2025, Deloitte found that the refurbishment share had risen to 66 per cent.
The Crane Survey data goes further. According to Deloitte UK, the total volume of refurbishment starts has surpassed the new-build start volume over each of the last eight surveys, averaging 2.3 million sq ft of refurbishment starts against 1.2 million sq ft of new-build starts per survey. The direction of travel is sharpening: SpecFinish magazine reports that refurbishment projects are forecast to account for 65 per cent of all new activity by 2030.
Even within the new-build pipeline, refurbishment logic is creeping in. Of the five biggest office developments to begin in 2025, just one (a 24-storey tower in the City known as the Dovetail Building) was a new-build project. The remaining four were refurbishments, according to Yahoo Finance, citing the Deloitte London Office Crane Survey April 2026. Total delivery of new office space across central London in 2025 reached 7.1 million sq ft, up 8 per cent on 2024, the third highest annual volume in the Crane Survey’s 30-year history. The reuse wave is not a sign of a sluggish market, it is happening inside an active one.
CircularBuild 2026 keynotes: from Copenhagen warehouses to walking cities
Anders Lendager, creative director and founder of Lendager, delivered the first of two keynote addresses. For Lendager, the conversation has moved beyond saving listed or culturally significant buildings. ‘It’s not about saving cultural buildings anymore,’ he told the room. ‘There are fewer and fewer cultural buildings every year that needs to be saved, but the fact of the matter is that we need to look at materials being cultural and natural heritage. That is what we need to save.’
His practice operates under the motto ‘form follows availability’, using what already exists on or near a site to determine design rather than specifying from scratch. The Copenhagen projects Warehouse 47 and Warehouse 53 illustrated the point: both converted 1950s industrial structures into mixed-use office buildings, retaining existing columns, beams, ceilings and walls, cutting into the fabric to admit daylight, and leaving the warehouse character legible. On the financial case for circularity, Lendager revealed that the exterior façade panels for the upcycled timber skyscraper Trae in Aarhus (a 20-storey building) cost just $10,000 in total. He also described receiving both a standard architect’s fee and a separate innovation fee on a recent Danish project, and argued that architects should expect to be rewarded for solutions that save materials, reduce carbon and cut client costs.
Thijs de Goede of Building Circularity Index developed a complementary financial argument. Buildings designed so that their components can be disassembled cleanly rather than demolished retain more residual value in those components. De Goede said buildings can increasingly be viewed as banks of reusable components, and that future material value should be factored into a project’s business case from the outset, particularly for owners with long-term interests such as housing associations or public bodies.
Landsec’s development director Sophie Morgan and Bennetts Associates director Peter Fisher presented Timber Square in Southwark as a worked example of brief-led reuse. The original 2019 brief set an embodied carbon target of 900kg CO₂ per m², required visible and reversible structural joints, and mandated a focus on longevity. The scheme retains part of a five-storey 1950s printworks, roughly doubling it in height, and adds a separate 15-storey block. Morgan told the conference: ‘It’s on all of us to create buildings that do stand the test of time, and so by putting longevity at the forefront of our brief, I think [we have ended up with] something that has a long life, that is flexible and can really adapt.’
Circularity in practice and what comes next
Joel De Mowbray, founding partner of Tipping Point East, urged delegates not to wait for the regulatory landscape to shift before acting on circular construction principles. Having launched the East London-based circular construction hub less than a year ago, he is eyeing up an expansion on the other side of London, aiming to sign another lease in around eight weeks to create what could be Tipping Point West. ‘I’m not really waiting for legislative change,’ he said. ‘Water doesn’t ask a rock to move; it finds its way around. Within existing regulations, I see it’s all there, it’s all possible.’
The closing keynote came from Reinier de Graaf, an OMA partner, drawing on his book Architecture against Architecture. De Graaf argued that building lifespans are growing ever shorter and that flexibility, adaptability and mobility should be the central concerns for architects going forward. Tackling embodied carbon he described as necessary but amounting to ‘good manners’; the deeper shift required was rethinking whether buildings need to be fixed objects at all. He pointed to the Hajj tent camp in the valley of Mina in Saudi Arabia, erected and dismantled each year, as ‘a massive city of completely movable objects’, and suggested the ideas of Archigram and Superstudio from the 1960s now carry a renewed relevance given accelerating urbanisation and sea-level rise.
CircularBuild itself will move to Brighton in 2027, where it is scheduled to be held at the Brighton Dome, a Grade I-listed Regency building.
