For example, Breda will build nature-inclusive at Nieuwe Mark | Bredatoday

BREDA – Work started this month in the center of Breda for the construction of the Nieuwe Mark. Where the river first stopped in the middle of the city, and fish, insects and plant seeds, so to speak, encountered a dead end, water and nature soon begin to flow through Breda again. Nature also returns in and on the frame. Eight organizations investigated how best to do this in the GreenQuays project. These results are now known.


How do you please the plants? In what type of wall, with what stone and mortar do the plants do best? Eight organizations investigated this in the GreenQuays project. For two years, they followed the growth of plants and mosses in a test setup on the corner of Karnemelkstraat. The results are now in and incorporated into the design. Koen Mulder, project architect and building technologist from Delft University of Technology, and Edwin Dijkhuis, project manager for species protection at Ravon, led the research.

And? What came out?
“That it is necessary to install a water-carrying ‘substrate layer’ behind the brick quay wall. Without this layer, the plants would die from lack of moisture. We have also discovered that by leaving joints open, we can speed up the establishment of wall plants. The open joints look like crevices in which plants grow naturally. Breda Municipality originally believed that plants would also grow in a sucking stone wall, ie a much thicker layer of bricks. With the test setup we could now test it.

With only rainwater on the walls, will there be no plants?
“The project has unequivocally proven that rich plant growth is only possible with a water-supplying substrate layer. The type of brick and the thickness of the brick wall have little effect on plant growth.

Traditionally, the quay wall consists of a brick wall with soil behind. But nowadays there is a steel punch in between. The brick wall is only there for the quay wall to look nice. But this also interrupts the moisture supply from the soil.

In this construction with the steel punch, the pilot showed that the plants will not survive with rainwater alone. They need a substrate layer. So if people went to look at the test setup and thought it will not work, all those plants will die, then that was right. There was no substrate layer behind most of the vertical strips of masonry. ”

Boats will soon be used on the Nieuwe Mark, so the construction must be robust enough. Therefore, you also examined the mortars. What came out of it?
“That a wall with two different mortars can be a good solution, in combination with the substrate layer. In two of the test panels, we used a constructive mortar to fasten the bricks together. The outside was scratched out and filled with a specific sealant in which the plants grow best. In the outer two centimeters, the plant can do what it wants, and inside the constructive mortar holds the wall together. ”

Do you also see the results of the research reflected in the design?
“In the final design, we chose the use of substrate, a fantastic result that we would not have had without our research. It is applied thinner than in the test setup.

The best finishing mortar for the plant will be a step too far for the quay manager. We had applied an imaginary mortar based on clay, in which we did it as optimally as possible for the plants. With straw in, and vervulite, and with a little lime. It is true that most of the plant growth came in this, but it also polluted the wall extremely. The second, similarly well-functioning, grout was eventually chosen.

What we see with all quayside trials to date is, the closer we get to implementation, or in other words, the further away from the trial, the greater the balance of interests. Breda and the engineering company balance sustainability, maintenance and safety on the one hand and plant friendliness on the other hand in the design. ”

What do you think, we should soon walk along the water in a park, as we see in the pictures?
“The design is based on spontaneity. The wall plants should establish themselves on the wall by their own power. It is a years-long process. The big difference will be that if you apply an optimal substrate and use the fantasy mortar, the quay walls will grow over quickly. If you do it in a moderate version, it will take longer. The quay walls turn green, but the question is how fast or slow. Quay management, or rather not managing too much, is also an important factor in this.

With the project, we started to look at it in a different way. Before, we were not crazy about plants in the walls, they only damaged them. Nowadays, a richly overgrown wall also adds something to our experience. And the wall plants and insects benefit from it. With this project, we show the importance of nature-inclusive construction and that it is possible. ”

On July 6 at 19-21, GreenQuays is organizing a city plant excursion. During this walk you will get acquainted with special wall panels and we will show you how the plant growth develops between the paving stones. You can still register via info@floron.nl

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