Nacka Green Walls and Roofs – Challenge

Bild1Title of your hackathon challenge
Green walls (and roofs) design for urban climate change adaptation

Describe your company or organisation
Nacka kommun is a fast-growing municipality just east of down-town Stockholm, with ca 100 000 inhabitants.

Describe your challenge
Nacka municipality, like many others, are facing increasing problems ahead due to climate change. In our part of Europe the scenarios show greatly increasing water precipitation all year round combined with occasional but more severe heat waves during summers. This poses great challenges for the urban planners and builders since Nacka currently is going through a rapid urbanization and densification at the same time as there will be less space for storm water run-off areas functioning as natural absorbents to prevent flooding.

Nevertheless, Nacka is trying out a number of new ideas and tools to prevent this loss of natural greenspace and ecosystem services, e.g. constructing open storm water management systems (LOD) such as “rain gardens” along road side curbs, nutrient retention ponds, semi-porous parking lots, green space factors etc. However well thought out these solutions are, they all need some kind of surface space, areas that in a more dense urban is hard to come by. Constructing green roofs are another alternative but has also its limitations, depending of the roof area used, kind of vegetation, types of climate zone etc.

But what if we somehow also can make use of the urbanization’s “hidden” space for water management – the lateral space?

More tests and reports are coming out with examples of buildings with “green walls” or “green façades”, many of them initially constructed for aesthetic or climate cooling reasons. But lately some reports also imply that certain types of vegetation panels (attached to the sides of buildings) can slow down the runoff of rainwater, which in theory could greatly aid traditional storm water retention systems on the ground beneath the buildings.

Specific environmental challenges for Nacka are the plans to construct truly tall high-rise buildings in some areas, areas that often are former brownfields and hence unfortunately have little natural green space to accommodate extensive rainfall runoffs. A further complication is the fact that a tall building is more likely to capture and “push down” additional rainwater (especially in windy conditions).

So what if a high-rise’s extra façade area could be turned into an environmental asset rather than a problem?


What kind of data and facts can you offer the team to solve the challenge?
Specific info, tentative test case:
Currently there is a comprehensive plan in making for the “Klinten” high-rise complex, situated by the 222 highway (Värmdöleden), fairly close to downtown Stockholm (Södermalm and Hammarby sjöstad), on a former factory/brownfield site. Storm water management issues, especially in regards to expected climate change forecasts, is likely to be a substantial issue for this planning project.

Here are general info about the plan and the procedure (English translation available by clicking “translate” on top).

There are yet no official architecture drawings but a “start-PM” describing the background situation and Nacka’s plans (in Swedish).

Nacka municipality’s urbanization strategies (English translation available by clicking “translate” on top).

Article in local newspaper about Nacka’s urbanization and high-rise challenges (in Swedish, for English use Google Translate).

Inspirational info about green façades etc:

Research articles:


What kind of solutions are you looking for?
We are looking for a set of creative examples of solutions somehow using this hidden “lateral space” on high-rise buildings to lessen the expected climate change impacts – mostly regarding storm water runoff but possibly also for heat/temperature control.

How are you planning to take the best solutions further after the hackathon?
The best solutions from the hackathon will be presented to the municipality’s town planning committee as well as posted on Nacka’s external web pages.

Name and contact info to person the team can contact regarding the challenge
Magnus Rothman, Environmental Analyst, Municipality of Nacka, Dept. of Environment and Urban Planning. Phone: +46 8 7187795, mobile: +46 70 4317795. E-mail: magnus.rothman[at]

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