Greening the Skyline with Green Roofs
Green roofs are a nature-based solution for cities to manage stormwater while restoring the natural environment. Read how The Hague is greening the skyline with green roofs.
Rooftops are often flat and so are conducive for capturing and holding
rainwater. Green roofs treat stormwater through retention or bioretention.
They comprise a structurally sound roof, waterproofing and root
barrier, a drainage layer, a permeable fabric, a growing medium and
vegetation. They can reduce annual stormwater runoff by 50–60%
on average and capture up to 85% of some water nutrient pollutants.
Green roofs also provide a range of multiple co-benefits, including:
- Reduced energy usage: Green roofs reduce the amount of energy needed for cooling purposes in warmer months and heating requirements in cooler months
- Improved air quality and reduced carbon emissions: Green roofs absorb air pollutants and intercept particulate matter in the air. They can also directly sequester carbon)
- Improved habitat: Green roofs provide habitats for animals and plants
- Increased public education opportunities: Green roofs enhance community awareness of NBS
The Hague’s Green Roof Subsidy
The Hague has launched a subsidy for the construction of green roofs throughout the city. A total of €600,000 is available for owners of homes and property (for example, business, schools, neighbourhood centre, or housing corporation) and for homeowner associations.
Applicants have till the end of 2021 to apply for the subsidy to recover the cost of constructing the green roof. The subsidy is set at €25 per square metre of green roof up to a maximum of 50% of the construction costs, with the maximum total amount set at €20,000 per application. Each application needs to meet a set of requirements, including:
- The roof surface that is planted is at least 6 square metres
- The green roof has a minimum storage capacity of 18 litres per square metre
- The green roof has at least one layer on top of the existing roof to form a physical barrier to prevent root penetration (root barrier membrane)
The Take-out
Green roofs manage stormwater while providing multiple co-benefits.
Join the conversation on the following LinkedIn groups: Urban Water Security, Our Future Water, Circular Water Economy, Blue and Green, Nature-Based Solutions, and Urban and Regional Futures
