Green Roofs as strategy to mitigate city problems (Part 2)

Following to what we said last week, about how good green roofs worked to mitigate Heat Island Effect, one of the biggest challenges of cities nowadays, we want to continue explaining how good they perform as well, when we talk about another huge city problem:
Water Storm Management.

Climate change is altering the natural water cycles and the rain patterns in mostly every part of the planet. It is increasing the seasonality of rainfall and risk of flooding. When this happens in a natural environment, the native soil by absorbs and filters the water thru its permeable condition, but in urban areas the impervious flooring materials and buildings structures send all the water directly to the underground drainage causing peak flows that damage dramatically the infrastructure. The risk of localised flooding effects is bigger therefore in the cities. Images of flooding all around the world are common now in our daily newspaper cause climate change, and the amount of them will just increase.

Green roofs reduce the amount of storm water run-off and mitigate the peak flow rates. In summer a green roof can typically retain between 70-80 % of the rainfall run off. (Living Roofs and Walls Technical Report. London 2008)

In cities, "green roofs" are a great method to help out reduce the Heat Island Effects and the Water Storm Effects, but beyond that, green roofs are excellent for other reasons. They increase the biodiversity of a place and they enhance the quality of the space. If combined with Solar Panels, they increase the efficiency of the photocells as they help keep them cooler thru the evapotranspiration. 

The fact that there are being installed mostly in temperate climate places such as Germany, doesn’t mean though that they perform worst in desserts or in other climates. In fact, as insulators, green roofs have a very high efficiency in hot climates, reducing the cooling loads of a building that would save energy demand.
The cost of the green roof in this case with the irrigation system that needs should be measured against those potential annual energy savings and the reduction of the cooling system. Intensive roofs perform as good as extensive roofs, but the cost, the irrigation demand and the maintenance is so high that is not recommended on dry climates.
In tropical climates, in places such as Singapore, green roofs will be great efficient since there will be no need for irrigation system and very little maintenance. Intensive roofs are more cost efficient here and they will provide their own benefits as enhance biodiversity and amenity space to increase the value of the property.
In cold climates such as Germany, green roofs are not so efficient as insulators but in a city context and done extensively they do contribute to mitigate heat island effects, water storm discharge and in the summer time help to reduce the cooling loads of the building. They don’t need irrigation system but they need insulation panels. Extensive roofs can be used as much as intensive roofs as they are both liable.

In Mediterranean climates, if done in a large scale, green roofs can help thru evapotranspiration to increase the amount of precipitation inland, as they raise the amount of humidity in the air, which is another big consequence of the dense urbanization in the coast areas. (Estudios Ambientales del Mediterraneo studies done by Millan Muñoz)

In general terms, we can say that Green Roofs are good for many reasons and they should be considered to be used almost in every situation. 

Go to www.livingroofs.org for further information. 

Image from ACROS Fukuoka Project in Japan.
Source: http://www.metaefficient.com/architecture-and-building/amazing-green-building-the-acros-fukuoka.html#more

Why Architecture must move towards sustainability? (Part 2)

A few weeks ago we started this “post series” explaining the big impact architecture had in the environment and the reasons why we must work on designs that recover its architectural essence and avoid the big emissions buildings produce now a days.

But, the question is:

HOW DO I MAKE A SUSTAINABLE BUILDING?

Besides the conditions and premises that any building with different uses states (is not the same to design a single house than a hospital building), there are several identical rules every architect should be able to apply to any of their designs.

1.    Understand the environment of the site. Climatology, orientation, local available sources for materials, traditional local construction techniques, etc. and design in order to adapt the building to those surroundings. Usually, the traditional local construction techniques have been improved and developed thru years to adapt the buildings to that area in particular.

Please, abandon the idea that you can design anything you want and then fill it up with high consuming machines to acclimatize the rooms. This is a mistake. We must consume less energy in our buildings.

2.    Never over dimension a building just for the fact of making the “King Size” effect. Bigger doesn’t mean better.

3.    Investigate deeper on design strategies that help to make buildings more and more efficient and environmental friendly. There are thousands of amazing solutions and techniques, and thousand more that are coming up everyday. In the Diagrammatic Section GUASL has made for this post, you can find a few of them, some very basic, some more sophisticated, but all of them out in the market to be used and improved.

4.    You can go for a Rating System such as LEED, BREAM, GREEN MARK, GREEN STAR and let them guide you thru the process of making a sustainable building. Those Certifications are made to standardize and give you a rating based on the performance of your building compared to a baseline. Taking a look thru any of its checklists and reference guide books will give you a very extended idea of how could you design greener. After achieving an award on any of this rating system, your building will be internationally recognised for its sustainable performance and you will save a lot of money afterwards in consumption.

5.    There are other fields that are actively investigating on new things for design strategies. Biomimicry Guild is a science that takes solutions from nature and applies them to solve human problems. They have fascinating stuff. Here you can find an example and see what I am talking about.
http://www.inhabitat.com/2007/12/10/building-modelled-on-termites-eastgate-centre-in-zimbabwe/

The Architecture Revolution has begun. Come on in.

Why Architecture must move towards sustainability? (Part 1)

Picture by Julian Hewitt

Architecture is everywhere.

There is not any modern civilization without architecture. It’s everywhere. Everyone needs a shelter, needs a house. Architecture has been present thru the history of human kind adapting to different climate zones, to different uses, to different aesthetic styles, etc.
Architecture has been always in evolution since the man settled down after the discovery of agriculture. It always had a bonding with the site it was placed.

So, what is happening now with the globalization? Why do we find the same type of skyscrapers in the desert of Dubai than in the cold city of Shanghai? Architecture is losing its essence of belonging to a place, so is to say, is losing what it took us so many years to learn: how to adapt our buildings to the different geographic conditions and make the best use out of them.

Architecture nowadays emits 60% of the worldwide emissions to the atmosphere. We, architects, are responsible for the CO2 that buildings produce and the climate change it causes. We, architects, have great power in our hands, the power to change things with a great impact.

The revolution of Architecture starts now.

We must go back to its essence, understand it, and then, in order to adapt to the new modern world demands, we must use technology to make it happen without harming the environment.

Cause Architecture is not made to harm the Earth.
That’s is not what Architecture is for.