Roofs occupy an enormous amount of surface area in our cities and yet only a small fraction of this space is used for solar panels – and even less for green roofs, despite the obvious benefits.
When designed primarily to shelter buildings from the rain, wind and sun, roofs may not always be easy to adapt for greener uses – but many can.
There is the equivalent of thousands of hectares of suitable roofs pitched perfectly for solar panels. Most of these are empty, though solar electricity generation is cheaper than that from fossil fuels.
A recent example of such adaptation is at King’s College, Cambridge, where the ancient chapel’s east-west alignment made its roof perfect for generating electricity.
It would be a significant boost for the UK’s climate goals, and a great example if every church in Britain followed this example.
Flatter roofs, of which there are many on factories, warehouses, schools andother buildings, can also be used to produce greener energy.
The simplest of these is lightweight clinker planted with sedums – succulent plants with fleshy leaves and flat, nectar-rich flowerheads.
The extra depth of the plants and clinker saves energy by insulating the building in summer and winter. It also retains rainwater, reducing the risk of urban flash flooding.
