Removing waterproofing from public housing: how social housing providers are making their buildings more eco-friendly

Removing waterproofing from public housing: how social housing providers are making their buildings more eco-friendly

It is not uncommon to find housing complexes from the 1970s where 70 to 80 percent of the outdoor spaces are paved. This architectural legacy poses significant challenges in terms of thermal comfort, stormwater management, and compliance with ESG reporting requirements.

Making this housing stock more accessible is both a means of improving tenants’ quality of life and a strategic priority in social housing organizations’ sustainable development policies.

A natural heritage with significant potential for restoration

Assessing the current situation: the first essential step

For a landlord managing 200 properties across several counties, accurately answering the question "What is my imperviousness rate?" is a complex task. Analysis of aerial imagery makes it possible to produce a comprehensive and consistent assessment within a few weeks: for each site, the proportion of impervious surfaces, vegetated areas, tree cover, and surface temperature.

The areas with the greatest potential

• Residential parking lots: often oversized, they occupy large areas that could be partially landscaped
• Internal service roads: can accommodate lateral landscape swales
• Schoolyards and play areas: priority candidates for "Oasis Courtyard" projects
• Building basements: can accommodate basement gardens

De-impermeabilization and climate resilience: the dual benefit

For tenants: thermal comfort and quality of life

In practical terms, an unpaved, green outdoor space means:

• Surface temperatures 5 to 15°C cooler in summer
• Better rainwater management
• A more pleasant living environment that reduces tenant turnover

For landlords: compliance and value enhancement

• CSRD: Reducing Exposure to Physical Climate Risks
• European Taxonomy: A Contribution to the Goal of Adapting and Protecting Ecosystems
• Sustainability reporting: indicators for green space, CBS, temperature

Plan and prioritize fleet-wide maintenance

The prioritization matrix

A multi-site diagnostic tool allows you to cross-reference multiple criteria:

• Current waterproofing rate
• Exposure to ICUs
• Vulnerable population density
• Potential for greening

This matrix enables the development of a streamlined multi-year investment plan that can be presented to the board of directors.

Run a simulation before committing funds

Simulation allows us to compare intervention scenarios before implementation: How many degrees are gained for every 200 square meters of unsealed and planted area? What is the impact on the CBSh? What is the potential for carbon credits?

The Low-Carbon Label as a Financing Tool

Planting projects on unsealed areas may be eligible for the "Low-Carbon, Tree-Lined City" certification. It’s a virtuous cycle: unsealing generates carbon credits, which fund new plantings, which in turn generate new credits.

Conclusion

Social housing stock is one of the most impermeable areas in our cities—and one of the most transformable. Social housing providers who tackle this challenge systematically—through assessment, prioritization, simulation, and measurement—are doing more than just meeting regulatory requirements. They are tangibly improving their tenants’ living conditions and building a strong case for their investors.

Would you like to assess the potential for removing impervious surfaces from your properties? Request a multi-site assessment.