Tall Tales

What’s the archetypal image that we carry in our minds about cities? Sky high buildings, 24/7 traffic, pollution, glitzy malls and most importantly, lack of green spaces. It seems that city dwellers are condemned to live and work in concrete, glass and steel structures which always seem to be missing something, inspite of clever use of colour combinations.

Now,medical science has long known that greenery reduces stress and elevates human mood. But trees need space to grow and as we know, cities have very little open space. Horizontal open space, if you count out rooftops. But they do make up for the lack of such spaces in profusion of vertical spaces  like the facades of multistoried buildings and  walls.

A new age architectural movement using such spaces to increase the level of greenery in cities has taken hold in recent years in Europe and now North America. What we get is something variously called green or living roofs and walls and looks like this

That is a green roof. If you are looking for a green wall, this is what you will get.

Notice how nice looking both these buildings are? A sight to soothe sore eyes. And also notice how much better the green facade looks in comparison to the plain concrete front on the left?

And its not even the exteriors that can be greened. Interiors can be as well.

Benefits of green walls and roofs

Apart from aesthetic factors, there are numerous benefits of greening walls and roofs. Unlike concrete, plants don’t reflect heat back, and a building in Chicago with a green roof is actually 14 to 44 degree Celsius cooler than the adjacent conventional buildings, leading to a corresponding savings of minimum 5% in electricity. Another study in Toronto estimated that 6% greening of roofs would cut annual GHG emissions by 2.4 megatons.

There are some other benefits that are not immediately apparent, but can be very important in the long run. Plants absorb water and therefore, green roofs can take the load off  stormwater drainage systems in many cities (especially relevant in Indian cities).Incidences of smog and ambient dust have also come down in areas where there is a significant percentage of living roofs. Heck, if you are the gardening type you could even grow your own vegetables and fruits on top and in fact there are plans for skyfarms that would feed upto 35,000 people in Toronto annually-a 58 story building, 1.32 hectare actual space and 8 million square feet of growing space.

Terminology, maintenance and resources

Sure green roofs have many benefits but what is the catch? Why aren’t people greening their houses and offices? For now, the sticker price is comparatively higher than normal roofs and walls,though it is coming down steadily. Of course, in the long run, the cost, if looked in context with other factors like electricity bills and a better living environment is much less than conventionally built roofs/walls.

Depending  on what you want, there are different ways in which you can go about greening your roof and walls. Most important thing to keep in mind is the type of plants; local species  are the best. Irrigation is also important, especially in context of walls.

For roofs a special type of compost which is also lightweight  is recommended.There are basically two types of roofs-extensive and intensive. While this site has an excellent FAQ a quick note- extensive roofs are cheaper than intensive ones and require low maintenance.

Google is your best friend if you decide to go down the road of greening your house. The green movement is heavily supported by municipalities in various cities across the West and resources are aplenty on the Net. Local bodies across US and Europe give financial incentives to builders who install green walls and roofs and Toronto is actually considering a building code that would make such structures mandatory. Obviously it will be a long time before something like that happens in India, but in cities like Hong Kong, Tokyo and Singapore there is widespread awareness and implementation of such walls

In case you need a little more inspiration this site features some stunning examples of living walls across the globe including a skyscraper in Mumbai, India said to the the world’s tallest and largest living wall.

Such places will probably make their neighbours go green with envy.