Articles Interviews

Interview with an Influencer – Dusty Gedge, living roof leader

PWC green roof dusty gedge

In the first of our ‘Interview with an Influencer’ series, Inside Ecology interviews Dusty Gedge…

dusty gedge interview

Dusty is a recognised leading authority on the design and implementation of green roofs, co-author of a guide to good landscape contracts and the Small-Scale Green Roof DIY Guide. President of the European Federation of Green Roof and Wall Associations, director of the Green Infrastructure Consultancy and founder of independent advisory organisation

How did you first get into championing living roofs and how did the concept of them develop for you?

It all started when I was asked to do bird surveys in Deptford Creek back in 1997. I used to do five minute surveys twice a month and during these surveys discovered several pairs of black redstarts which at the time (as they still are today) were protected species under the Wildlife and Countryside Act, which makes them a material consideration for a planning authority or a developer to do something for them during a planning application.  So we used this mechanism to get developers to put a habitat on the roofs.

At the time we didn’t know anything about green roofs, nothing at all, and it was between 1997 and 2000 that a group of us including a few people from the London Biodiversity Partnership decided to really investigate what this idea of green roofs was. Most of the green roofs being used in the UK were really only sustainable building ‘fluff’, there were a few interesting examples that my colleague Gary Grant had been involved in back in the early 90’s, but really the systems from 1997 to around 2004 were off the shelf lightweight systems.  We had the idea that we wanted to put brownfield habitat on the roof, a post-industrial landscape, which a lot of nature conservation people in London and in the wider Thames Estuary area were really interested in, in terms of it being very valuable for wildlife.  The black redstart because of its protected status almost became a flagship for this.

So we came up with the idea of the ‘brown roof’, which was quite useful at the time because it started the idea of putting green roofs for biodiversity on the map for planning departments, statutory organisations and organisations like the London Wildlife Trust.  It seemed that 1997 was the year that people started to think about green roofs outside of the core countries like Germany, Switzerland and Austria.

You started out as a keen bird watcher, have you hung up your binoculars?

Green roofs have taken me all over the world and I have bird watched all over the world on every single continent except for Antarctica and Africa, so yes, I am still bird watching.  

However, I spend a lot of my time in the UK looking at insects and other bugs.  Around the year 2000 we discovered that there was a guy in Switzerland who was studying biodiversity on green roofs (Dr Stefan Brenneisen), I went to see him in Basal and the rest is history – we have done a lot of work together since.  His work was in looking at how you can redesign green roofs to support invertebrates.  A lot of people in the green roof industry didn’t like those ideas because they were ecological and didn’t fall into one homogenous system that is easy to lay and easy to buy, so Dr Stefan’s work was challenging to the continental/Swiss market at the time.  

I took this up and set up an MSc which led to a PhD in London, doing exactly the same thing, looking at green roofs in London and seeing how they can be designed better, which led to the Buglife green roof guidance;  this guidance is nearly the basis of everything that’s written about biodiversity and green roofs in the UK – essentially, the idea of creating green roofs for biodiversity is based around creating flower rich, replicated habitats with varied substrate depth.  

But unfortunately, ecologists can tend to make it complicated and that’s where we bring in the brown roof idea, which was initially about putting up crushed brick and concrete and seeing what self-seeded, which in principle sounds great if you’re an ecologist, but if you are a building manager it’s not a great idea because crushed brick and concrete attracts in the first instance, plants that you don’t want on a roof e.g. buddleia, which can cause major damage to buildings – so you need to be not just an ecologist or a nature conservationist but somebody who understands issues like waterproofing and building integrity.   

If you look at using crushed concrete – the most important thing on a green roof of any kind is the ability for the substrate to hold water and concrete doesn’t hold a lot of water therefore it’s not a great product to use.  It’s great using concrete for reasons like waste disposal/re-use of waste, but for creating interesting nature conservation habitats, it’s not a good idea.  

One of the things I learnt is ‘don’t be purist’ and that’s why ecologists and landscape architects sometimes make green roofs too complicated and then they end up failing.  By using green roofs the idea is that we are not restoring, we’re replicating circumstances and the best circumstance to replicate, or the easiest at a green roof level, is a calcareous flower rich stressed environment which meets open mosaic habitat criteria.  Green roofs won’t solve all the ecological problems that you find as a result of losing brownfield sites, habitats such as wetlands and scrub, but they can deliver really interesting things in terms of dry grasslands.

Black redstart (Photo Credit ©Dusty Gedge)

Black redstart (Photo Credit ©Dusty Gedge)

How do you think the UK is doing in terms of living roof installations and their popularity?

We just published the UK Green Roof Market Report – a market research report I was involved in over the last 12 months.  

For the last 6 or 7 years I’ve been estimating what’s been going on in the UK and accurately mapping what’s been going on in London; what the market report shows is that the market is increasing by 17% a year across the UK.  We also know from conversations with our colleagues in Europe, that outside of the main markets of Germany, Austria and Switzerland, London is in the top 9.  What’s frustrating is that when there are articles written about green roofs, London rarely gets mentioned – per citizen, we have more green roofs than most other cities in the USA.  So London is doing pretty well outside of Germany, Austria and Switzerland.

42% of the UK green roof market is focused on London and that’s because we have a policy which is quite effective as applied by the GLA [Greater London Authority].  Green roofs are expected on all new major developments and the Boroughs take that down to their remit.  Generally, green roofs are now mainstream in the architectural world in London.

If the UK doesn’t have it right when it comes to living roofs, which country does and what can we learn from them?

In essence, the UK, along with Switzerland, is at the cutting edge of how you deliver green roofs for biodiversity.  If green roof design follows all the guidance that we’ve written and it is installed correctly, and the establishment and initial maintenance in the first two years is done, we can create some really good green roofs in the UK and we are doing so.  Therefore, I don’t think we’ve got that much to learn, in fact we’ve got lots to teach other people – even if you went to the main markets in Europe, most of those are 80mm sedum roofs, there for stormwater runoff and nothing else.  So actually, we are probably at the cutting edge of green roofs but we don’t talk about it enough.

What do you think we can do to encourage more living roof uptake?

As outlined in the Green Roof Marketing Report, what is exciting, is that we now have the new metro mayors as voted in this year, which have similar powers to London to create strategic planning decisions. I am pretty optimistic that within the next two to four years, most of the authorities that have that power to create strategic planning will have some kind of green infrastructure policy, which will almost definitely include some kind of policy about green roofs.

What is important though is creating those policies and then creating guidance on what that mayoralty wants i.e. green roofs designed for ‘X’ – we have to be prescriptive there to ensure that landscape architects and architects design with that in mind and that the ecologists understand that they are now designing on buildings and not everything goes.  You can create interesting wetland habitats, which I have done on roofs, but you have to really know about green roofs – the green roofing companies etc. can get a lot of bad press but if they are bought on board they can actually help innovate.

Policy is always going to be the thing that helps deliver more green roofs – wherever you are in the world, green roofs will only be delivered by good, far-reaching policies.

There are some innovations going on outside of policy for example some property developers are making their own aspirations such as net gain for biodiversity on all of their developments, and that’s going to include green roofs

What are the common misconceptions you have encountered with regards to living roofs and how do you respond to those reluctant clients and architects who fear that installing a living roof will add significant costs to a project and onerous maintenance?

There are many misconceptions including maintenance, leaking, increased steel upload, associated extra costs, if near to airports people are concerned about attracting birds – to be honest, these are people clutching at straws and finding negatives not to do it.  

If you look at it over a sustainability agenda, there’s actually no reason not to put a green roof up because for the integrity of the building it protects the waterproofing, from fire, leaking, you can store lots of rainwater if done properly, part of the SUDs cycle, but the problem is that many architects aren’t interested in green roofs, and generally when they have to do one they want to buy the quickest, cheapest solution, they want to buy a product rather than an ecological landscape – those attitudes are implicit within the construction industry and it’s difficult to move an industry like the construction industry whose remit is to use the same solutions in all their developments.  But having said that, there are lots of green roofs going up and it’s pretty mainstream these days in the capital.

What is the most surprising species you have encountered using a living roof?

Someone did once send me a photograph of a Pileated woodpecker on a green roof in Portland, Oregon, which I thought was pretty cool.

I did enjoy going out to a small green roof in Essex that my friend John Little designed.  We were up there with about 20 people looking at a dense thicket of vegetation and there was an old partridge nest in there – what I liked about it was this green roof, about 100m2 in size, was in a landscape of agricultural factories and probably the noisiest place for that red-legged partridge to nest was that green roof.

I once planted ladies bedstraw on a green roof in Camden around August time 2011 and whilst planting it a hummingbird hawkmoth turned up, which was pretty cool.

There’s a wonderful orchid roof in Zurich, Switzerland and it’s pretty incredible – the species diversity up there.

Laban Dance Centre - Original brown roof in Deptford, London 14 years on (Photo credit ©Dusty Gedge)

Laban Dance Centre, Deptford, London – original brown roof, 14 years on (Photo credit ©Dusty Gedge)

Is it possible to successfully meet the needs of building users and wildlife through living roofs – can the two be integrated successfully?

Years ago I did a talk in London and an Australian lady came up to me and said “does that mean that I can go and have my lunch in wilderness on a roof” and I said that if I had my way then yes – she thought that was great.  

What was interesting about that conversation was that generally the attitude to most people who are involved in building design, believe that these messy type of roofs are alright on roofs that nobody can go on but because they are not highly manicured and designed, people wouldn’t be interested in going out on them – I think that attitude is a convention and not necessarily true.  

Every year as part of Open Square weekend in London, one particular green roof that I was involved in helping transform, for a legal firm on Cheapside in London, open up their green roof to the public and it’s great.  About 4000 people visit that roof every year and you’ve basically got people walking around a wildflower rich habitat, something I find really interesting.

But essentially, the cultural norm is you can’t design these roofs for people to go on because people will want high-end park/garden type design.  

I have just come back from Berlin and went onto a roof associated with a public housing project, which is great – you go up onto the second storey of these twelve storey blocks and the roofs are all flower rich meadows; around the green roofs are little benches, so essentially it is a wildflower meadow with benches around it where people can sit and enjoy the meadow.  I asked how people react to it given it isn’t a designed garden and you can’t let your dog out onto it for example, and the general feedback was that people like to come and enjoy nature.

I think that people would enjoy sitting in less manicured spaces – a place where they can sit and enjoy being part of nature. At the moment, architects and landscape architects struggle with that as a concept.  

Have you seen any noticeable change in attitudes to incorporating sustainable systems into developments?

Definitely – I think we have created a culture of green roofs in London; we’ve created a culture of biodiversity in London. I think that is not quite filtering out as much as we would like beyond London, although there are a lot more green roofs outside of London than there were before.  

How can we improve the way we approach living roof design?

The main problem of green roof design is the construction industry – you can design and specify a really good green roof, which goes to the designers and architects and then it goes through planning and it’s signed off by planning and then I go and look at it two years later when it’s installed and from the moment it has left the designers to the moment it is being installed there’s a whole other process that goes on that is all about cost cutting.  

We’re unlikely to see an improvement until the Green Roof Code of Practice is respected by the architects and the designers and they accept that if a green roof is being priced at nearly half the cost of all the other reputable suppliers, you know that you’re going to get a bad green roof. The good green roof installers are losing work as a result of a bunch of really bad green roof installers who come in much cheaper and then it’s done badly because nobody really cares about it.

Unfortunately, planning authorities aren’t able to police these things – if we could find some kind of mechanism to ensure that poor and badly installed green roofs are stripped out and the construction industry realises it is going to be penalised (stripping out a green roof costs a lot of money), then you will start to see the main contractors and the whole construction industry taking it a bit more seriously as that is where the main problem lies.

Ecologists and landscape architects need to put into their fee quote that they need to inspect the green roof when it has been installed and make clients do that, because if they know they are going to be inspected, the installation will probably be a lot better, and for the cost of that inspection, it’s minimal.  

I am optimistic that green roofs are doing well, about 60% of the ones that I have designed are installed well, whereas ten years ago I would say that figure was 10%. So a lot of this is about creating cultures – we have created a culture of green roofs, what we need to do now is create a culture of quality green roofs and that’s the next step for the next ten years.

So what’s currently in the pipeline? What projects/campaigns are you working on at the moment?

I’ve been mapping London green roofs, over the last few years since 2006 (I’ve also mapped Budapest and Brussels). We’ve got funding to create artificial intelligence about how we can use this mapping potential; we are looking at how we can take this forward to another scale. This is where I am thinking that we can use artificial intelligence satellite data to actually start creating a database and an intelligent machine, learning an algorithmic way of being able to analyse green roofs online to help put some quality into what essentially should be a quality green roof market.   

Further information: All photographs ©Dusty Gedge. Dusty can be found on Twitter @greenroofsuk. Dusty’s design work is run through his consultancy: Green Infrastructure ConsultancyHe is also running a day workshop in September in Essex – Design Landscapes and Gardens for Rare Invertebrates – check it out HEREThe UK Green Roof Market Report can be found HERE.