THEY have been called “gardens in the sky” and could become a key weapon in the battle against climate change.

Green roofs - roofs which are partially or completely covered with vegetation and can range from a simple layer of wildflowers and mosses all the way up to more elaborate environments featuring shrubs and trees - are an increasingly common sight on buildings across Europe.

They help protect against flooding, shelter wildlife and provide a taste of nature to those living in urban areas who may not even have access to a back green.

But they are rare in Scottish housing, with the perceived cost thought to be discouraging developers.

There is also no mandatory policy for green roof infrastructure north of the Border and current planning guidelines place little weight of ‘expectation’ on firms to integrate them.

Now, in a bid to transform the situation, a major report has been unveiled setting out options for how a 596-home development next to the new Meadowbank sports centre in Edinburgh might look with the feature included.

And, as leaders at City of Edinburgh Council prepare to consider whether the ideas can be progressed, hopes are high that the document could help green roofs become “the norm” at residential projects throughout Scotland.

Ivan Clark, Placemaking Team Manager at Scottish Natural Heritage, which, along with the Scottish Government, funded the options report, said the benefits would be wide-ranging.

“It’s like having gardens in the sky,” he said. “[Green roofs] provide habitat for wildlife and particularly pollinators such as bees and butterflies.

“And, where you can provide people with access... and the areas are properly maintained, you could even grow food.

“Green roofs slow down the rate of water run-off from a site during very heavy rain, reducing the risk of sewers backing up and causing floods because the volume of water is too great.

“It’s using nature-based solutions to deal with the challenge of large volumes of water.”

He added: “Meadowbank is a good place to develop green roofs because it will have a range of different sizes of building.

“It will have tall buildings that could accommodate intensive green roofs – with larger shrubs and trees.

“But there will also be smaller two or three-storey buildings where a less intensive green roof could be the right solution.”

The relative rarity of green roofs in Scottish housebuilding contrasts with their growing popularity in many cities around Europe.

London has been successfully increasing the infrastructure through its land-use planning system for the past 10 years.

Paris has a target of installing 100 hectares of green roof and walls by 2020, while Stuttgart in Germany requires all new developments to have the feature.

Mr Clark said the Meadowbank report showed that it was possible to install the roofs for limited additional cost, something he hopes will encourage firms to include them more often.

“It’s a bit more expensive than a conventional roof at first, but not by much, and it pays for itself pretty quickly because of savings in energy bills,” he said.

“We looked at the numbers. It’s actually a very modest uplift with green roofs in terms of the initial capital cost.

“In Edinburgh there are a few examples of some really nice green roofs but they tend to be part of office accommodation. More generally, and especially in terms of housing, they are not that common in Scotland - they are really quite rare.

“We are hoping that construction firms, developers and the housing sector can see the benefits of incorporating this. We want green roofs to become the norm.”

Councillor Kate Campbell, Housing, Homelessness and Fair Work Convener at Edinburgh council, said: “As a council we have an ambitious target for Edinburgh to be a net zero carbon city by 2030 and I think we have a real opportunity to embrace green housebuilding at Meadowbank.

“One idea has been to consider the use of green roofs and we’ve undertaken a study to understand how this could work, but whether we’ll progress this won’t be known until later.”