24.02. 2026

Barcelona wins the Bloomberg Mayors Challenge, for the second time. Here’s what made it work.

Barcelona has been named one of 24 global winners of the Bloomberg Mayors Challenge 2025-2026, selected from more than 630 cities worldwide. The city receives $1 million and operational support to scale Renovation-as-a-Service — a new model for making home renovation accessible and affordable for residents who need it most.

For UpSocial, this is the third time we have contributed to a winning Mayors Challenge collaboration — after Barcelona in 2014 and Rotterdam in 2022. But more than a milestone for us, it is an opportunity to share what we learned from this process, and why we think it matters for cities working on public innovation.

The problem was not what it looked like

More than 372,000 Barcelona residents live in aging buildings without elevators — facing extreme indoor temperatures, limited mobility, and growing social isolation. The need for renovation was obvious. What was less obvious was why so little was actually happening.

The conventional answer pointed to financing. More subsidies, more credit lines. But the evidence told a different story: 40% of renovation processes stall not because of money, but because neighbours cannot agree on what to do. The system did not have the necessary trust, and the stakeholders had perverse incentives.

This was the turning point. Barcelona was not facing a housing renovation problem — it was facing a collective action and governance problem embedded in the fabric of the city. Reframing the challenge in those terms changed everything about how the solution was designed.

The solution: activating what was already there

Renovation-as-a-Service (RaaS) does not create a new institution or parallel structure. It redesigns the role of existing ones.

The model rests on four components:

Municipal financial guarantees that unlock private capital and reduce borrowing costs for communities. We learnt that the risk of default is very low among communities of property owners.
Building managers trained as consensus facilitators, people already trusted by residents, now equipped to guide collective decisions.
Re-Habita, a digital platform that makes technical diagnostics, financing options, and administrative tracking transparent and accessible.
Integrated cross-department governance, reducing fragmentation and cutting approval timelines by 40%.

What the results showed

During the prototyping phase, the model demonstrated both behavioural and structural impact. In its first two years of full implementation, RaaS is expected to improve housing conditions for more than 9,000 residents, reduce the time needed for communities to reach renovation agreements by 40%, and mobilise significant private investment through public financial leverage.

Behind those numbers: residents like María, 72, who can now leave her home every day again thanks to a new elevator. Families with lower energy bills. Communities that have learned to act together.

Three things we keep learning

Across three Mayors Challenge editions, we have seen the same pattern. The cities that win — and more importantly, the cities that deliver — tend to do three things:

They diagnose the real bottleneck. Not the most visible one, but the one that is actually blocking progress. In Barcelona’s case, it was not finance — it was the inability of neighbours to reach a shared decision.
They strengthen what already exists rather than building from scratch. Building managers were already there. The city’s role was to equip them differently.
They align finance, governance, and behaviour. A financial guarantee alone would not have moved this. Neither would better facilitation without the digital platform. The three components had to work together.

What comes next

With Bloomberg Philanthropies’ support, Barcelona will now scale Renovation-as-a-Service as a flagship housing initiative. The project is led by BIT Habitat Foundation in collaboration with the Municipal Housing Institute (IMHAB) of the City Council. As part of the global Mayors Challenge network — which connects more than 250 municipalities — Barcelona will also contribute to international knowledge exchange on housing innovation and urban governance reform. UpSocial will be part of this process.