Green roofs to make Leiden future-proof!

If we look at climate adaptation of the city of Leiden, the main goal is not to fight nature, but to work together with it. While climate is changing, life in the city changes as well. The more extreme weather causes floods, droughts, higher and lower temperatures and the city cannot always handle this. That is why it is necessary for the city of Leiden to adapt to the climate. One way to do this are green roofs. If you do not know what a green roof is, watch this video to know all the basics.

Green roofs can solve a lot of problems that climate change brings. Green roofs absorb water during heavy rainfall, so that sewers do not overflow. Green roofs keep the inhabitants cool during the hot summer and most of all, it keeps people dry. Also green roofs can provide a habitat for wildlife to increase biodiversity and it can increase the air quality in cities (Oberndorfer et al. 2007). Green roofs mean less consumption of energy because it keeps you warmer in the winter and cooler in the summers.

Green roofs will become also more economically attractive in the future. Now a green roof is in comparison with a traditional roof 10-14% more expensive at a life span of sixty years. If the climate keeps changing and extreme weather will occur, the green roofs will become more and more attractive to prevent flooding and extreme heat in cities because of saving money on energy consumption and other techniques to prevent flooding (Castleton et al. 2010). There is an initiative in Leiden to get more green roofs. It is called Groene Daken Leiden and helps citizens to get subsidies for green roofs. It is based on an initiative of Amsterdam and it is making great progress. If you want more green roofs in your neighborhood you can ask them for help to get subsidy. Then you can help Leiden to adapt to the future in a more sustainable way for only a small fee. In the picture below you can see a project they did at the Boerhaavelaan in Leiden.

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The benefits of green roofs are endless for the environment and for the people living under them. Green roofs are a great way to get more green and plants in the city and increases the aesthetic value of neighborhoods. Green roofs are also a great method to reduce noises and living in a busy city this can be of great value! Green roofs does not demand a lot of maintenance. Only in periods of drought is it necessary to water your roof, but even a dryer roof will keep all it functionality and benefits (Getter & Rowe 2006).

Leiden is a very dense build city and has a strong heat island effect. This means the temperature in the city is on average 3 degrees Celsius higher than in rural areas. With rising temperatures because of climate change this can cause a lot of problems for the city, such as droughts and higher mortality rates during heat waves. If we want to keep the city a nice place to live, things have to change for future generations. Green roofs can provide a solution to make Leiden future-proof!

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8 thoughts on “Green roofs to make Leiden future-proof!”

  1. Hi Renee,
    Thanks for this post! I love the idea of green roofs, because they provide a lot of ecosystem services! It would be wonderful if green roofs can solve a lot of future-problems in Leiden. Nevertheless I’m a little bit worried about the additional mass placed on the old buildings in the city centre. Can they support the amount of added weight, especially when they absorb water during heavy rainfall as you mentioned? Perhaps it will be possible to create a kind of structure above the buildings, so weight is supported by another frame?

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    1. Green roofs replace shingles so most of the times they are a bit lighter. Although, it can be too heavy for a few older buildings. Most of the times these older buildings are also historic or monumental buildings and are protected against alterations such as green roofs.

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  2. Nice blog! I fully support the idea of green roofs. I think the video shows very well the great variety of green roofs. However due to the substance of most Leiden buildings it will be very difficult to actually install them to the steep, old and probably historically listed roofs.

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  3. Nice title indeed! It’d make a great slogan for advertising the green-roof project. I am curious about the estimated amount of fee one may need to install a piece of green on his or her roof. I think it would be more attractive and encouraging if the amount of fee of installing a green roof per square meter per year can be showed.

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  4. I would love to have more green roofs in Leiden. They would be very helpful for tackling climate change and would also look great! I do however foresee problems with implementing green roofs in Leiden. Students form a big part of the population of Leiden and they generally live in rented houses. No less than 55 percent of all the houses are rental! (Source: cbs)
    This raises the question, who is going to pay for the green roof? I read on the site of Groene Daken Leiden that you can get a subsidy. But since there are no clear financial benefits, it is unlikely that a landlord would be motivated to apply for one. How can we make green roofs more financially attractive?

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    1. In the long run, green roofs can become cheaper because you save energy. Altough I agree that rental homes can be a problem, but a solution can be that the city funds more. Also, I think green roofs should be applied when building new rental buildings.

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  5. Great plan, like you also mentioned biodiversity can greatly benefit from this as well! If I remember correctly I think it’s possible to create a shallow green roof with sedum species at an angle up to 40 degrees, so while of course plenty of roofs are still too steep, there should definitely be the possibility to install this in Leiden.

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  6. First I have to say I’m really enthusiastic about this plan. It really seems as a good solution for climate adaption! But I don’t know if everybody will be as enthusiastic. Who has to pay for them? And what about the conservation? Who is going to take care for that? And I’m wondering if people would like to have such a garden on the rooftops. Little people would like to have solar panels on their rooftops… so I’m wondering if they are open to garden rooftops.. Again! I hope that I’m wrong! It would be a great idea.

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