How green roofs help cities breathe — and cool down Across Europe, summers are becoming more extreme. Urban centres, with their dense building materials and limited vegetation, amplify the effects. This phenomenon — known as the urban heat island effect — turns cities into climate traps. Asphalt, metal, and concrete absorb heat during the day and release it slowly at night, keeping temperatures high long after sunset. Green roofs offer a quiet but powerful way to break this cycle. Why Cities Get Hotter — and Stay Hot In urban areas, surface temperatures can be 5 to 7°C higher than in surrounding rural zones. Several factors contribute to this: Low albedo materials: Dark rooftops and pavements absorb rather than reflect solar radiation. Lack of vegetation: No shade, no evapotranspiration. Dense building patterns: Limited airflow traps heat between structures. Exhaust and waste heat: From air conditioning units, vehicles, and industry. These conditions don’t just cause discomfort — they

A straightforward guide to how green roofs work — and why they matter Green roofs are often misunderstood. Some see them as luxury landscaping, others as a niche architectural flourish. But a green roof is not simply a garden on a building. It’s a functional layer of infrastructure — designed to regulate temperature, retain water, filter air, and extend the life of the roof itself. So what exactly makes a roof "green"? And why does that distinction matter? Layers With Purpose At its core, a green roof is a multilayer system built atop a conventional roof structure. It typically includes: A waterproof membrane, protecting the building structure from moisture. A root barrier, to prevent plant roots from damaging the membrane. A drainage layer, to manage excess rainwater and allow oxygen to reach roots. A growing medium (not standard soil), engineered for weight, drainage, and nutrients. Vegetation, selected for the local climate and project goals — from hardy sedums to native pollinator

Turning underused rooftops into climate adaptation assets Cities across Europe are heating up. In the summer of 2023, Rome, Athens, and Seville recorded some of the highest temperatures in their histories. Heatwaves are becoming more intense, more frequent — and more deadly. At the same time, extreme rainfall events continue to strain drainage systems, causing urban flash floods with growing regularity. These are not isolated events. They’re the symptoms of a changing climate acting upon hard, impermeable cities. But amid these surfaces lies a largely overlooked opportunity: rooftops. The Potential Above Our Heads Green roofs — also called living roofs — are vegetated layers installed atop buildings. More than a design choice, they offer a form of nature-based infrastructure that cools cities, retains rainwater, improves air quality, and creates biodiversity pockets in dense urban fabrics. They help cities: Mitigate the urban heat island effect Reduce stormwater runoff Improve insulati