Collaboration is key

Many speakers made the point that retrofit is a team sport. Engineers, architects, cost consultants, demolition contractors and fire specialists need to be involved early and work from a shared set of information. Without that, projects stall or default to demolition. From my experience, too many project teams still think about the details too late.

Profitability is a barrier

Retrofit is rarely viable without adding floor area. Canary Wharf Group spoke on how, in their experience, a 20–30% uplift in floor space is often required. That leads to extensive cut and carve interventions, with new atria, and rooftop extensions. All of which relies on solid structural understanding of the building and capacity checks along with coordinated services planning. This is true for many of our recent commercial projects, which focus on vertical extension or finding other inventive ways to expand floor space, including Rose Court and Bethnal Green Road.

A skills hurdle blocks wider change

There is a general lack of practical retrofit expertise. Working with existing fabric and environments is complex, and these projects bring a wider range of challenges that are harder to predict from the outset. They often involve changes of use and conflicting regulations. Many clients only appoint teams who have comprehensive retrofit experience, as they understandably feel those teams have a broader base of knowledge to draw from. To grow the market, experienced and newer practices need to work together, share lessons, and help contribute to the baseline of knowledge across the industry.

The point resonated. Emerging practices have the potential to bring new ways of thinking and become future pioneers in sustainable retrofit, but only if they can clear this initial hurdle. It’s one we had to overcome ourselves. Those who currently dominate the market are in a position to focus on the collective benefit of the sector, rather than seeing every opportunity as a competition. Perhaps larger, more experienced practices could be more open to answering questions and sharing their knowledge with newer designers as part of day-to-day project work, not just at conferences and in closed spaces. Even informal mentoring, or open technical forums, could help demystify retrofit and lower the entry barrier for practices who want to do it, but have not yet built up a track record. The Engineers Reuse Collective, for example, has taken steps to build this kind of platform, but it needs to be adopted much more widely.

Surveys and information are a priority

Several speakers stressed that comprehensive surveys are essential before design starts to fully understand the existing structure, services, materials, and condition. Unknowns must be identified and allowed for in programme and cost. Digital models should be based on real investigation, not assumptions.

This rings true. Too often we still see projects rush into design with only partial information, which unravels budgets and programmes later and makes clients more cautious about retrofit in the future. All designers have a responsibility to push for better surveys when we see them being overlooked, even at the earliest stages, because engineers will often not yet be on board to raise these issues.

Current regulation slows progress

Fire safety, building regulations, and change-of-use rules were cited repeatedly as the biggest barriers to retrofit. The need for early engagement with building control, insurers, and fire engineers to agree a workable approach came up over and over, but my takeaway was that we also need to look at the bigger picture. IF_DO gave an example with one of our own projects, the Observer Building, and how the introduction of the Building Safety Act caused frustrations, complexities, and additional costs for the later phases.

I have seen how conservation restrictions can limit straightforward energy upgrades. At the same time, building regulations do not always reflect how traditional or historic buildings behave. For example, adding internal insulation to solid walls can trap moisture and damage original fabric, yet existing guidance only partially addresses that risk. This is not about fewer conservation restrictions or regulations being wrong. It’s that the two frameworks are set up in parallel and applied separately, which can create friction that slows retrofit. More shared research, clearer pathways, and a common pool of practical knowledge would give everyone more confidence to do it well.

Circular economy needs structure

The supply chain for reuse is not set up at scale. Procurement, ownership of materials, and processing capacity all need to improve if salvaged materials are to be used more widely. On large estates, this can be planned across portfolios. On smaller jobs, it is still difficult. Echoing my colleague Rosie in Building Design, a universal, regulated framework for reliable structural and material records is needed to make reuse decisions easier and less risky. It cannot be left to competing firms to develop their own systems in isolation.

Designing for flexibility

The demands of the workspace have changed significantly in recent years. Occupants now look for open plan spaces with abundance of daylight, access to outdoor space, and adaptable layouts. Structure and services should be planned to allow future openings, extensions, and changes of use, not just the immediate brief. Something we ourselves wove into the fit-out of our new London office.

An example of what’s possible

An in-practice case study that stood out for me was Stanton Williams’ work with the London Museum, moving its home from the London Wall site to West Smithfield. The design makes minimum interventions and reuses around 70% of the existing fabric. The main challenge for them has been compliance, rather than ambition. Repairs are being handled pragmatically, not cosmetically, with the design adapting to embrace the challenges faced along the way within the final outcome. This approach feels fitting, given the museum’s purpose of telling the story of London’s history, but I wondered whether other clients and designers would be open to the same level of adaptability.

A call to do better

The conference didn’t reveal any major developments in the sector. It confirmed that the barriers we already know about are still slowing progress. I did, however, walk away with some new ideas about how my colleagues and I can approach these issues in our own work, and I hope that those in an even stronger position to influence policy and industry took away similar conclusions. The event also showed that many teams are already achieving exemplary retrofits by navigating the barriers with careful planning, early collaboration, knowledge sharing, and a willingness to adapt. If more clients, designers, and contractors apply the same principles, retrofit could become the default.