By continuing to use the site you agree to our Privacy & Cookies policy

RAISING THE ROOF

TECHNICAL & PRACTICE

Last week, I found myself at a fundamentalists' rally by mistake. I had been asked to report on the AJ's 'Green Roofs for Architects' conference, but found myself instead at a religious convention of the environmental fraternity.

Architecture is a soildestroying business. Apparently, there is a turf war going on and we need to encourage a grassroots movement. We need to find the inner yew.

The message was clear:

green roofs are more than the sum of their parts. They are not just sedum on stratum, but are part of a Movement in which architects need to 'get their message across'.

What message might that be? Well, primarily it is the idea that green roofs are a way of saving the planet from human intervention. Green roofs might look nice, said Jonathan Hines from Architype, but that's not a reason to install them.

Unless you've thought of the green roof as simply a part in the armoury of an architectural biodiversity strategy, then you shouldn't do it.

Roger Davey - an irrigation specialist who naively advocated that roof plants be watered - was ostracised as a technophile. Part of the beauty of nature's bounty is that it dies, he was told. How dare we intervene with that natural cycle? What wondrous colours dead foliage creates atop the roof. Mark Harris of Sarnafi l spoke about the need to nurture the 'plant community'.

Next, an advocate of sustainable urban drainage (also called ditches), insisted we mimic natural drainage.

Even though the ditch often has a French drain beneath it to aid water flow. A soakaway/ infiltration basin at a factory in Switzerland doubles as an irrigated swale (ditch) in which to grow crops. I was reminded of 1920s Stalinist autarky, when factories grew their own food because they couldn't rely on centralised delivery.

Dusty Gedge - an adviser to governments, NGOs and the green roof industry - pointed out that Switzerland is showing the way by hosting the World Green Roof Congress in Basel in September. Gedge, from Livingroofs. org, said the good thing about Switzerland was that regulations are imposed rather than pontificated about, as is the case in Britain. This difference, he said, is because the Swiss 'don't want their Alps to melt'. There's nothing like scientific clarity on these issues, is there? However, the dictatorial situation in Basel will loom large for the UK, if Gedge gets his way.

'All roofs in Basel, ' he said, 'are designed for rare insects.' Remarkably, all new flat roofs in Basel have to be designed with some form of vegetation, and the strict by-laws require such vegetation to protect endangered species of birds, bugs and beetles.

In the 1990s, I remember much-publicised cases of prestigious road-building projects being held up because of the discovery of a newt or somesuch. Today, prioritising nature is commonplace and it is striking that no one ever poses it in terms of human benefit.

Sustainable drainage consultant Bob Bray said it used to be difficult to get an appointment as a landscape designer; now he justifies his involvement in terms of a natural drainage and biodiversity adviser. More than 250,000m 2 of green roofs are proposed around King's Cross and the Greenwich Peninsula in London to protect the Black Redstart bird (see over).

Many of these roofs are not supposed to be walked on.

Why not demand that these be impressive rooftop gardens for people? I suppose that you'd have to get rid of the defecating birds and the infuriating bloody insects first.

For further details on the World Green Roof Congress, visit www. greenroofcongress. unr. ch

Have your say

You must sign in to make a comment.

The searchable digital buildings archive with drawings from more than 1,500 projects

AJ newsletters