Green Roofs
Some environmentalists believe the answer to some of London’s environmental problems lie in the planting of green roofs – but what are they?

Inside Out
Watch Inside Out every Monday on BBC One at 7.30pm for surprising stories from familiar places. Plus you can watch each edition of the London programme straight after transmission for up to a week. Use the links on the right of the page. It’s something the Tellytubbies have known for years. Living underneath a green roof is good for you and the environment. Sound silly? Well some environmentalists believe the answer to some of London’s environmental problems lie in the planting of green roofs. And now some big businesses in the capital agree.

What are green roofs? As the name suggests they are intentionally vegetated roofs, (not ones that have just gone a bit wild through neglect!), in reality anything from a roof top garden to short turf or a scattering of mosses and lichens. Also now known as brown roofs or eco-roofs when used for conservation purposes; the basic motto for green roofs is that nature doesn’t just live in the countryside – buildings can provide fantastic habitats for wildlife too. Green roofs provide a cheap way of alleviating flooding, combating global warming and improving air quality, something we all need in London. But they also provide locally tailored conservation as well as improving the aesthetics of the city. They’re a new phenomenon in London and the wider UK but have been all the rage in Europe for decades. In particular Switzerland and Germany have been planting green roofs for almost 100 years. If you have a roof over a certain size in those countries you are required by law to go green! One of the first green roofs in Britain and probably the most famous are the Kensington Roof Gardens built in the 1930s.

Today the Mayor and his Urban Task Force – headed up by the architect Richard Rogers – are actively seeking to promote green roofs in London. And let’s face it – we’ve got a lot of underused roofing in the capital! Paul Collins from Nottingham Trent University is an expert on the science behind these roofs. He says they are an effective way of helping to stop flooding as well as reducing greenhouse gas emissions.

Paul Collins
“They act like a sponge really”, he said. “If you don’t have any greenery, water can just run off the concrete roofing and adds to the rainwater spill off. This adds to the flooding which we’ve had in London over the last few years. But if you have a green roof then the soil and plants catch a lot of the water absorbing it. And of course any green area reduces the amount of carbon dioxide in the air.” Already many buildings have gone green on top including the Liffe building in Cannon St, Jubilee Park in Canary Wharf and North Haringey Primary School in Tottenham. There the kids have the chance to explore a wild garden on their rooftop. It was a once disused smoking area for teachers – but within a few months a concerted effort by parents, teachers and pupils has created a wild play area which not only is pleasant to look at, it’s become a great teaching resource. But perhaps the most unusual place for a green roof and certainly the highest in Europe is on top of the new 160metres high Barclays HQ in Canary Wharf. The roof is intended to become an oasis for birds and insects in the surrounding area. “Barclays has the highest living roof in the world specifically designed for nature conservation and the enhancement of local biodiversity,” said Dusty Gedge of Living Roofs, who advised on the creation of the roof. He adds: “It is a beacon for other businesses and developers to provide similar roofs in the London area and elsewhere in the country for other species of nature conservation concern.

Dusty Gedge
“Building a roof designed for biodiversity so high hadn’t been done before. We didn’t know whether the soil would simply blow away, or if a truly bio-diverse culture could spring up so high above ground. In the end we needn’t have worried and I’m delighted with the end result. The roof is specifically designed to attract one of the UK’s rarest breeding birds, the black redstart. It was planted in May and is now fully bedded in. Although now crammed with insects and appropriately enough for a bank – a colony of money spiders – there’s no sign of the redstarts as yet. It’s one of the UK’s rarest breeding birds with fewer than 100 pairs recorded each year. But, there’s a mating pair close to the Barclays building, and in the 1980s there were 14 pairs in the Isle of Dogs. So it’s hoped they will make this very high nesthole a regular haunt! The roof is beginning to ‘green up’ and by next summer there will be an array of wild meadow flowers for the birds to feast on. Biodiversity on the roof will be closely moni ored by the University College London as a biological research project to help inform how future green roofs with a focus on biodiversity should be designed. Unfortunately because the roof is so high the only people to get a view of it are workers on the top floors of Canary Wharf or passengers on planes whizzing into nearby City airport. But it’s certainly a high profile example of what can be done – to add a splash of natural colour to our city!

If you want to see an example of an accessible green roof in London, you can visit the Horniman Museum in Forest Hill. Website: www.horniman.ac.uk

Tel: 020 7224 2424
e-mail: yourlondon@bbc.co.uk