‘Good Urban Practice’ brings more green to cities

Hertogensite/Janseniushof: greenery up to the roof of the underground parking spaces

The Hertogensite, the former hospital site in the heart of Leuven, is being transformed into a new city quarter. Whereas in the past this historic site mainly housed care, the new interpretation focuses on ‘unburdening’ future residents. Here people will live in a green environment along the Dijle, which will once again flow above ground, amid historic buildings and numerous commercial facilities. A place where housing, nature and culture merge into a whole that honours the past and embraces the future. And Disaghor-Dockx guarantees the ‘green roofs’!

Those who love nature had better come and live in the centre of Leuven these days. Because the formerly petrified hospital site is being redeveloped into an inner-city green lung in which water and nature play the leading role. Besides the abundance of greenery, the ‘Aa’ and ‘Dijle’ watercourses will also be given oxygen again. The latter traverses the area from north to south, forming a structuring and image-defining element of the Hertogensite. The entire site is strongly anchored within the surrounding urban fabric, by numerous green thoroughfares, boulevards, squares and cycling and walking paths. The 1.6-hectare central city park, with its sunbathing lawn sloping towards the banks of the Dijle, forms a central resting point. The tree species chosen guarantee ecological diversity and the flowery hay meadows add an aesthetic touch.

Lots of greenery, including on roofs

But in this case, the greenery was also extended to the roofs of most of the buildings. An expert in the field is Disaghor-Dockx. The company is one of the main suppliers for (garden) contractors and public authorities in Belgium. Through a strong network of depots and technical support ‘on the field’, they are an important trading partner for all companies and authorities active in ‘green space’. Indeed, the Ruiselede-based company, currently managed by Sébastien de Cartier d'Yves and Celine Van Rijckeghem, takes the greening of urban environments very seriously, partly through their ‘Good Urban Practice’ project. 

Intelligent long-term vision

Sébastien de Cartier d'Yves, managing director Disaghor-Dockx: ‘Gradually, the liveability of our urban environments in Flanders, Brussels and Wallonia is reaching its limits. Our ‘space’ has become a scarce commodity. In this respect, Flanders is one of the busiest regions in Europe. The steady growth of the population and annexed villages and cities create unprecedented pressure on the living environment and nature. Resolutely opting for integration of ‘green’ within spatial planning shows an intelligent long-term vision. Via ‘Good Urban Practice’, we want to inform the various actors about the latest possibilities for jointly achieving sustainable, social, economic and ecological integration of ‘green’ in public space.

Green roof construction the only solution

Sébastien de Cartier d'Yves, business manager of Disaghor-Dockx: ‘A lot of green areas were provided for De Hertogensite and Het Janseniushof. That greenery was even extended to the roof of the underground car parks. And because we had to start from a concrete slab, a green roof construction was the only solution. For this we worked with substrate on the drainage system, 50 cm at Hertogensite and 40 cm at Janseniushof. At the places where the trees are, we then raised the substrate. Moreover, to prevent the trees from blowing over, we placed a concrete net on top of the drainage material. The root ball anchorage was then attached to this.’

‘Where the parking spaces are, sub-base lava 0/32 was used as a sub-base plus a laying bed. On this laying bed substrate, we then placed the grass slabs. The pathways were then worked out again in mixed rubble with stabilisé on top, and the clay clinkers were placed on top. On the Hertogens site, phase 3B, moreover, almost everything is permeable to water, think cobblestones with grass joints, cobblestones with gravel, grass tiles and Nidagravel with gravel. This project was carried out by Q-landscape bv from Zoutleeuw, in collaboration with general contractor Algemene Bouwonderneming Vandebos nv from Alken.’