BWI–C40 Learning Tour | Vienna, Austria

Vienna’s built environment transition is not framed as a “green upgrade” to business as usual. It’s treated as a public-good project: housing as a human right, climate resilience as a necessity, and decent work as the backbone of delivery. This was the main lesson at the joint learning tour organised by the Building and Wood Workers’ International (BWI) and C40 Cities Network on 30 June – 1 July 2025, in Vienna, hosted by GBH Austria, NHG (Neue Heimat / GEWOG), GBV, and the City of Vienna.

Across two days, delegates from unions, cities, and allied organisations explored how Vienna manages to combine large-scale affordable housing, low-carbon and circular construction, and strong industrial relations that protect jobs, wages, and safety.

“The Vienna model is about partnership. It connects workers as builders and citizens, people who construct the city and also need to live in it. You don’t get clean construction at scale without a social housing system, and you don’t get a social housing system that lasts without worker engagement and public policy.”

Paola Cammilli, Global Campaigns Director, BWI

The journey: From housing governance to circular construction in practice

The model: Social housing as a generational contract

The tour opened with a deep dive into the Austrian limited-profit housing system, led by GBV and GBH / NHG, showcasing why Vienna remains a global benchmark for affordability and stability. Participants explored how limited-profit housing associations provide homes for around a quarter of Austria’s population, with cost-based rents designed to stay stable over time, reinvesting surplus into new housing and renovation rather than profit extraction. The model’s philosophy was repeated throughout the day:

“House for people, not house for profit. This isn’t “housing for the poor.”  Vienna’s approach is built for social mixing, quality, and long-term affordability, so housing supports life cycles and family needs across generations.”

Gerlinde Gutheil-Knopp-Kirchwald, GBV

The worker imension: Union leadership makes the system work

Vienna’s housing success isn’t just financial engineering—it is collective bargaining, enforcement, and workplace democracy. GBH highlighted how union power supports the model by:

• fighting social dumping and underpayment,
• anchoring sector-wide wages and classifications,
• supporting apprenticeships and skills pathways,
• and ensuring worker voice in broader housing and procurement decisions.

The group discussed how climate action in housing (renovation, low-carbon materials, heat adaptation) must translate into real protections and opportunities for workers, especially in a sector shaped by subcontracting pressures in many countries.

“A right to housing changes the roots of the market. It sets the parameters, and it must be built with decent jobs.”

Christian Fölzer, GBH

The city scale: Seestadt Aspern and building the 15-Minute City

Day two shifted from the “model” to the “city”, with a guided visit by Kurt Hofstetter (City of Vienna Planning) to Seestadt Aspern / Quartier am Seebogen, one of Europe’s largest urban development projects and a flagship example of integrated, low-carbon urbanism. Participants saw how Vienna designs sustainability as a systems choice:

• public transport first (the metro arrived before full build-out),
• walkability and services planned around the 15-minute city,
• ground-floor activation to avoid dead malls and create community life,
• and rules to prevent land speculation, including leasing rather than selling public land.

A practical circularity example stood out: material extracted during the creation of an artificial lake was reused on-site, even enabling a temporary cement production solution, turning infrastructure works into a circular construction input.

“Cities are where climate solutions get tested. Vienna shows how community engagement, affordable housing, and low-carbon construction can move together.”

Dan Daley, Clean Construction & Just Transition Senior Manager, C40 Cities

Circularity With a social purpose: BauKarussell and “Social Urban Mining”

The tour concluded with a visit to BauKarussell, where delegates saw what circular construction looks like before demolition, through selective deconstruction that preserves materials for reuse and creates pathways for labour inclusion. The group learned how procurement and tendering can be designed to support:

• material recovery and reuse,
• safer, planned dismantling instead of destructive demolition,
• and social integration by linking deconstruction work with partner organisations.

It was a concrete illustration of “regenerative built environment” as more than carbon: it’s also jobs, skills, inclusion, and smarter resource governance.

“From demolition to opportunity, social urban mining proves circularity can create both decent work and real material recovery.”

Thomas Romm, Romm Architects / BauKarussell

What made the difference: Policy + unions + partnerships

Across every stop, the same thread reappeared: Vienna’s results are not accidental. They come from long-term public policy, strong social partners, and a housing ecosystem that treats affordability and climate resilience as non-negotiable. This is why delegates repeatedly described Vienna as a replicable direction, not a copy-paste project: the institutions may differ elsewhere, but the principles travel.

Key takeaways for a just transition in the built environment

Affordable housing and climate action can reinforce each other

Energy-efficient homes and low-carbon construction reduce living costs and emissions at the same time—if public policy locks in affordability.

Worker engagement is a climate strategy

Strong unions help prevent social dumping, secure training and fair wages, and ensure transitions don’t become cost-cutting exercises that harm safety and quality.

Cities can hardwire equity into development

Land policy (leasing vs selling), participatory tender evaluation, and “public transport first” planning show how governance decisions shape climate outcomes.

Circular construction must be designed and procured

BauKarussell shows that reuse doesn’t happen by goodwill; it needs methods, time, standards, and procurement rules that value recovery and labour inclusion.

What this means for the future

The Vienna Learning Tour, supported through the broader learning partnership around clean construction and just transition, reinforced a simple truth:

You can’t decarbonise housing without protecting workers, and you can’t scale affordable, resilient housing without treating it as a public good.

Vienna offers a blueprint for cities and unions working toward a regenerative built environment: homes that are affordable, climate-resilient, and built with decent work at the centre.