Extensive Green Roofs

An extensive green roof is a lightweight, low-maintenance vegetated roof system with a shallow soil layer (usually under 200mm) that supports drought-tolerant plants like sedums, mosses, and wildflowers, primarily for environmental benefits like stormwater management, improved air quality, insulation, and urban biodiversity, rather than human access. They are self-sufficient, economical, and ideal for retrofitting existing buildings, providing ecological advantages with minimal structural impact.
Key characteristics:
  • Shallow substrate: Thin soil layer (5-20cm).
  • Lightweight: Adds minimal load (from 55 kg/m²).
  • Low maintenance: Rarely needs watering or extensive care after establishment.
  • Drought-tolerant plants: Uses hardy species like Sedum, grasses, and wildflowers.
  • No human access: Not designed as usable garden space.
Main benefits:
  • Stormwater Management: Slows and reduces runoff.
  • Insulation: Enhances thermal performance, reducing energy costs.
  • Biodiversity: Creates habitats for insects and birds.
  • Air Quality: Filters pollutants and reduces the urban heat island effect.
  • Aesthetics: Softens the visual impact of buildings.