A green shade roof for Grenchen
Jakob Rope Systems has developed a case study for a green shade roof over the market square in Grenchen. Rudolf Lehmann explains the idea behind the design.
In many cities, there are places that offer little protection from the sun and heat on summer days. These heat spots could be made more pleasant with greenery and shade. Green climbing structures would be a solution for developing attractive urban spaces.
Jakob Rope Systems is currently presenting how such a solution can be realized for the market square in Grenchen. At the request of the town, Jakob Rope Systems has developed a case study for a free-standing shade roof.
The town of Grenchen wants more shade. Why is this need so urgent?
The market square in Grenchen is a typical case of a heat spot. When the sun is at its zenith here on hot days, the square heats up. Added to this are the surrounding facades. They accelerate the development of heat as they prevent air circulation. A shady roof with greenery could provide a remedy here.
A roof made of mesh structures and climbing plants could provide shade on the market square in Grenchen. How realistic is this idea?
We show a fully developed project study that can be implemented structurally. Climbing plants as fast-growing greenery on a free-standing climbing structure - this concept works. Our previous projects for Basel Zoo, for MFO Park Zurich and most recently for a shade roof in Oerlikon demonstrate this.
How did this project study come about?
The starting point was our study for the Red Square in Solothurn. This proposal for a shade roof was met with interest by the town of Grenchen. We were approached and developed a study for a shade roof on the Grenchen market square. During development, we involved partners from the fields of botany (raderschallpartner AG, Markus Fierz) and urban planning. Our engineering team calculated a climbing structure made of ropes and nets, including static requirements.
What effect does a green shade roof have in an urban space?
The shade provided by plants and their leaves cools the space below. The roof above the ground creates an attractive space in which people can spend time. As the seasons change, the plants will display different inflorescences. A beautiful alternation of colors and scents is created. The green roof provides shade and quality.
Conventional solutions, on the other hand, would be ...
... trees, of course. However, they need a root pit of at least 10 to 15 cubic meters to grow. This underground space is often occupied by pipes or sewers. Then there is the time horizon. Trees need around 20 to 40 years to form a crown that provides sufficient shade. Another solution would be parasols. These provide shade, but do not create the cooling effect caused by the evaporation of leaves. Biodiversity would also not be achieved with parasols.
Where in cities is the potential for greening greatest?
I see potential in city centers with large open spaces that are surrounded by buildings. Cooling air circulation is not possible here. Then on the facades of buildings. Also on walls that run alongside railroad lines or roads. I'm also thinking of above-ground parking zones. All these areas get very hot in summer.
How does the planning and construction of a shade roof project work?
We carry out the implementation of such a shade roof with the client from the initial idea to the finished building. We also bring on board the necessary project partners for botany, urban planning, metal construction and authorities. In this way, we offer cities and planners a useful overall package.
How long does it take from construction to complete greening?
We reckon on around six to eight years. This is the time it takes climbing plants to grow over a shade roof about seven meters high from the ground. Decisive factors for growth are the height of the shade roof, the size and type of plants and care.
What obstacles have you encountered so far with such greening proposals?
In urban areas, different interests and structural requirements come together. We and our clients have to take these into account. In some areas, there is also a lack of legal foundations that allow authorities and developers to respond to questions and objections. Access routes, escape routes and fire safety requirements also have to be taken into account when building in urban areas. However, we can solve these issues technically very well.
What does the draft for Grenchen contain?
A load-bearing steel structure that stands on eight base points. Supporting ropes stabilize the steel structure. A stainless steel net is attached to the steel structure as a climbing structure for the plants. The irrigation system for the ground-based greenery is integrated into the shade roof. The shade canopy is 16 meters wide and 100 meters long. The climbing plants grow from the base points.
How high is the maintenance effort (compared to conventional greening with trees)?
The steel construction and our stainless steel nets are virtually maintenance-free for 30 to 50 years. The only thing that remains essential is plant care, which should be carried out once or twice a year. This is necessary because climbing plants grow quickly. The shade roof in Grenchen would require a lifting platform to reach the roof. We have already taken this into account when designing the footings. Numerous individual plants are planted for the greenery. If a plant dies, it can be replaced.
Downloads
The program is presented in two parts. In the GreenSolutions reference brochure, you will find many real-world applications that show you the potential of greening.
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The program is presented in two parts. The catalog GreenSolutions Technical contains all wire rope products with their technical information for your greening project.
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