Researchers in Hong Kong have concluded that modular green roofs would be an easier option to install in high-density cities than systems built on the roof and may encourage more building owners to make their roofs green.

Dr Sam Hui, from the University of Hong Kong, told the World Green Roof Congress that the city, which is densely populated and known for its skyscrapers, wanted to make its skyline greener.

“In recent years there’s been a growing attention to green roofs because it’s believed that it can be a very good urban greening method in Hong Kong,” he said.

The University carried out a study to look at which method of creating the roofs would be most suitable for large cities such as Hong Kong or London.

“For cities like Hong Kong, if you are going to carry out installation of green roofs, it will affect the normal operation of the building so we are looking at ways that we can make the installation more convenient for the building owners,” he said.

“The modular approach is simple and quick installation. It has an instant effect.”

He said that the study recommended the roofs were used on buildings with few storeys, such as schools, rather than high-rise offices and tower blocks.

“We believe that it will be much more effective to look at applying green roofs in some very low-rise or medium-rise buildings.

“Occupants from the surrounding areas will be able to enjoy these green roofs.”

A Swedish study of green roofs installed on recycling buildings in residential areas found that although most were still functioning ten years later, others had suffered from vandalism, overhanging trees or steep surfaces.

But Tobias Emilsson, from the Swedish University of Agricultural Sciences, said some maintenance would always be needed to ensure green roofs continued to work.

He said: “I think in Sweden green roofs have been sold as maintenance free. It’s taking a bit of education to show that no roof is maintenance free.”

Kate Martin

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