What a wonderful town, sorry, city, we live in. Our local permaculture trust in partnership with Brighton and Hove Building Green recently put on a 2 day course about creating green roofs. Such is the international reputation of the 2 key speakers that delegates on the course had come from far and wide, including Argentina, Greece and Haywards Heath. And I just had to walk up the road to Varndean school. Perfect.
It was inspiring on several levels. First, it was an excellent example of how to run a great training course. Well thought out, good information clearly delivered, with the right balance of practical, theory and some site visits. The practical session had us building our own section of green roof to take away as a reminder of the various layers involved. The theory bit, consisted of tons of great photos of all sorts of green roofs, before and after shots and lively delivery by the 2 key speakers. Dusty Gedge is responsible for establishing Livingroofs.org, the first not-for-profit company to provide independent advice on green roofs in the UK. In collaboration with John Little who’s been creating all sorts of beautiful green roofs for the past 10 years, they’ve written a great DIY guide to making green roofs. You can see examples of John’s work at the Grass Roof Company.
The other level of inspiration was that I left feeling empowered, or to use Dusty’s new favourite word, facilitated, to go and create not one, but 2 new green roofs of my own. Currently our 2 bikes are under a not very attractive grey plastic cover to keep the worst of the weather off them. A gale wind resulted in the plastic ripping, so it’s now nicely adorned with some heavy-duty black tape… So, methinks it’s time to make a timber framed bike cover, with sloping green roof that will change with the seasons and provide visual interest all year. I see this bit of my garden from the kitchen/diner and the lounge, so if I can make it more attractive, and grow yet more plants – I will. Hoorah to all involved. You can find more information on the course providers at Brighton Building Green and Brighton Permaculture.
The course covered retro-fitting an existing roof – eg. the flat roof over the tiny extension on the back of my house, as well as designing a green roof into new buildings, including sheds, garages, house extensions and houses. Understandably, some people fear that growing plants on a roof will result in a damaged roof, possibly causing leaks. The course stressed the importance of the water-proof layer (butyl pond liners, for example) for new green roofs, and a root barrier layer (again, a pond liner will often do) to stop plant roots damaging an existing roof – this applies when retro-fitting. The 2 most damaging things for roofs are UV light and extremes of temperature, as anyone who’s ever stood on a roof will verify. So, by adding a ‘green’ layer, you’re actually prolonging the life of your roof, as you’re protecting it from these elements. You’re also, insulating the room below, making it cooler in the summer and warmer in the winter. Obviously, it’s got to be properly designed, specified and constructed, but I left the course feeling confident that it’s actually quite straightforward. The range of what can be grown varies according to the depth of substrate or growing medium, which in turn is informed by what you want from your green roof, and the load-bearing capacity of the roof itself. The ‘look’ can range from common sedums through to a grassy-meadow look or more ornamental flower border and even vegetables. The 3rd speaker, Hanna Waldbaum, gave a facinating presentation on growing food on roofs based on her thesis ‘Green Roofs for Urban Agriculture’.
Green roofs are fantastic for wildlife – including us. As well as creating habitats for all sorts of mini-critters, yes, including our beloved bees, there’s plenty of research showing that green spaces are good for humans. In addition to being lovely to look at, the evapotranspiration effect, results in cooling our cities in summer (less need for air conditioning) and using the surface run-off water that may otherwise result in local flooding.
All in all, it seems like a marvellous idea to me, and I’ll keep you posted on the development of my own experimental green roofs over the coming months.
Lisa Attwell Lilybud Garden Design
Popular Items