Construction of the Demonstration Areas

As part of the project, we constructed two demonstration areas to illustrate different green roof systems. Prior to construction, material lists were prepared to calculate the required quantities and estimated costs for both areas.

Extensive Green Roof

The first demonstration area represents an extensive green roof system. A wooden frame was constructed as the base structure. Afterwards, a substrate layer of approximately 10 cm was installed. We chose a single-layer substrate consisting of a mixture of gravel and extensive roof substrate.

To demonstrate safety measures commonly required on green roofs, we also installed a fall protection system with a safety rope. One of the main advantages of extensive green roofs is their comparatively low construction, maintenance, and operating costs compared to intensive green roofs.

Finally, Sedum species were spread across the surface and thoroughly watered to ensure successful establishment and growth.

Intensive Green Roof

The second demonstration area represents an intensive green roof system. Before construction began, we prepared a detailed sketch and planned the installation of a viewing window to make the layer structure visible and easier to explain.

As with the extensive roof, a wooden frame was first constructed. The wood was then lined with a protective foil to prevent damage from moisture and other environmental influences. Next, a rigid drainage layer was installed and covered with a filter fleece. This prevents brick chippings and substrate particles from entering the drainage layer and impairing its function.

The next layer consisted of approximately 8 cm of crushed brick, which serves as a substructure substrate. This layer provides structural stability and prevents excessive settlement of the substrate over time. In addition, its high mineral content contributes to good drainage and long-term stability.

Afterwards, approximately 40 cm of intensive substrate was added. On the third and fourth project days, an irrigation system was installed. We chose a drip hose system because it provides an even and water-efficient distribution of water.

Planting of the demonstration area began once the irrigation system had been completed. The plants were selected from the experimental garden. As our group wanted to focus on edible plants, we chose the following species:

  • Leek (Allium porrum)
  • Chives (Allium schoenoprasum)
  • Strawberry (Fragaria × ananassa)
  • Sage (Salvia officinalis)
  • Mint (Mentha sp.)
  • Lady’s Mantle (Alchemilla mollis)
  • Currant (Ribes sp.)
  • Rosemary (Salvia rosmarinus)
  • Lemon Balm (Melissa officinalis)