Copenhagen currently has about 30 planted rooftops. In future there will be vastly more.
The City of Copenhagen’s has decreed that any new flat roof with a slope less than 30 degrees must be planted with green vegetation.
The new guidelines make the capital to the holder of the world’s most ambitious policy on green roofs.
Only Toronto in Canada is approaching the level of ambition with its requirement that all new flat roofs must partially planted.
Engineering and Environmental Mayor Bo Aamus Kjeldgaard is excited about the new green policies.
“I have the goal that the whole of Copenhagen will be much greener, and that the green roofs will give CO2 savings ‘, he said.
The plants on the roofs also insulate against cold and heat, allowing the building to conserve energy. It should help the municipality to achieve its objective to be CO2 neutral in 2025.
Furthermore, the plants will clean urban air and act as absorbent sponges when it rains, so sewers and sewage plants will be less loaded.
It is estimated that green rooftops will grow at a rate of about 5000 square meters per year.
The new guidelines do nit require that the roofs should be accessible, it will be up to developers to decide whether they will seize the opportunity to create recreational areas with views of Copenhagen.
Today Copenhagen has about 200,000 square meters of flat roof space, but the new political initiative contains no requirement that they be planted.
The government feels it cannot compel building owners to plant green roofs, but it can educate owners to the benefits and demystify the risks.
The municipality is providing incentive funds for those who want to convert their roofs to gardens.
Creating a green roof is slightly more expensive than conventional roof solutions. It costs around 500 kroner (£50) more per square meter, equivalent to about 0.5 percent above the total construction costs – calculated for buildings above three storeys.
“For the small additional investment you get in return a roof with a double life and a building that is future proof in terms of environmental requirements”, says Bo Asmus Kjeldgaard.
The policy is being welcomed by Copenhageners, being described by Bo Asmus Kjeldgaard “crazy hip”.