Green Roof Load & Irrigation Calculator

Work out saturated load per m², check it against your roof’s structural capacity, and estimate weekly irrigation for an Australian green roof.

Roof area (m²) Substrate depth 80 mm – Lightweight 100 mm – Standard extensive 150 mm – Semi‑intensive 200 mm – Intensive Custom depth Plant load extra (saturated) Succulents / sedum – +30 kg/m² Grasses – +60 kg/m² Shrubs – +150 kg/m² Small trees – +300 kg/m² Custom plant load Roof structural capacity 1.5 kPa – Patio / car‑port 2.0 kPa – Typical residential 3.0 kPa – Light commercial 5.0 kPa – Heavy commercial Custom capacity Calculate