Green roofs can improve the energy efficiency of a building!

Green roofs are plantings growing on roof tops. They are engineered as a multiple-layer construction, designed to support vegetation and protect the roof construction underneath. Green roofs are said to offer a range of ecosystem services, and in this way benefit to sustainable development of cities. The often mentioned benefits include: reduction and delay of storm water runoff; reduction of urban heat islands (UHI effect); improvement of air quality; increased energy efficiency of buildings; reduction of noise pollution; extended lifespan of roof materials; and improved conditions for biodiversity and wildlife. Green roofs are also said to increase amenity value such as access to new parks and gardens, give positive mental and physical benefits from view to and access to green surroundings; and to provide space for food production.

Now, let’s look a bit more into one of the claimed services: Improved energy efficiency of buildings. Green roofs are claimed to be able to improve the energy efficiency of a building. In hot summers they keep the building cold, and in cold winters they reduce the need for heating. The cooling mechanism is through the evaporation of water from vegetation and substrate. The incoming solar energy cannot heat up the building, because the sensible heat is turned into latent heat in the water vapour. In winter time the need for heating is reduced because the green roof provides insulation of the building. When the substrate of the roof is well-drained it contains a lot of small air pockets, which serves as an insulating layer.

Do you agree? YES or NO

Pick some keywords in the text above on green roofs and energy efficiency and use them as search terms. Identify at least five sources supporting the statement.

What’s reliable and unreliable?
You have probably already sources you think are reliable and others where you’re not sure if they are reliable or not. So on that background choose now two sources, one source you think is reliable and one that you think is unreliable. And both sources should confirm the statement you choose: “yes” or “no”.
(A source is a website, an article, a book etc.)

Now select two sources out of the five you have identified….

Now you pick one of the two and go through the next four criteria steps:

1. Objectivity
2. Reliability
3. Accuracy
4. Relevance

For each step you mark how sure you are, that this source is objective, reliable, accurate or relevant
Where 1 indicates very unsure and 5 indicates very sure

You can get some help by clicking the Hint and get a hint!
Hints are questions that helps you to interrogate the source:

·   Who authored this text?

·   Who benefits from this text?

·   What voices are being heard?

·   Whose voices are left out?

·   Is there another point of view?

Source number 1 – here we go!

Now you take the second sources and to go through the four criteria steps.

For each step you mark how sure you are
And you can get a hint!

Source number 2 – here we go!

Now place your two sources where you think they belong:       Not so good              OK                   Good

And this is how you do it:

Choose the right place for your source above. This will open a “Padlet”, which is like a shared, digital note wall. Here you add a note for each source.
Type in:

• Name and type of source
• Source link
  
• Why is it Not so good, OK or Good?
  
• Your names

This is a preparation for a group reflection in plenum.

Relevant study resources: Landscape Architecture and Urban Design

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How to search literature, guidance

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