The green roof is more and more popular for its irresistible charm and its excellent resistance. It brings cachet to a house in the country and even in town. Far from being a simple decoration, it also serves as a covering just like tiles, sheets, and other materials dedicated to the roof. Sedum is one of the most recommended plants for green roofing. Here are the reasons why.
A Resistant Sedum Roof
Also known as orbs, sedum is a genus of the succulent plant family. These types of plants are known for their exceptional ability to store water. Thanks to their mucilaginous juice stored in their vacuoles (large cells), they can resist extreme drought conditions. For the sedum, the liquid juice is held in its fleshy leaves. If this plant is the star of the green roofs, it is due to its capacity for adaptation to the variations in temperatures and the various climates. The sedum can withstand both drought and frost
A Decorative and Practical Sedum Roof
The sedum is also very popular as a green roof for its aesthetic and practical side. Thanks to its root system, it can quickly cover the roof’s surface. This type of extensive green roof requires a low substrate thickness, whether it is composed mainly of sedum or other plants (purslane and moss). For quick implementation, it is sufficient to lay a pre-cultivated mat after first installing a drainage layer and a waterproofing membrane.
Sedum also keeps its colors fresh all year long. Contrary to popular belief, sedum flowers come in various colors, including red, white, yellow, and blue.
Optimized Insulation With a Sedum Roof
Green roofs are also highly valued for their thermal performance, as they keep heat in winter and cool in summer. A green sedum roof is even more efficient. It provides a perfect cover that guarantees optimal thermal insulation. During periods of drought and heatwaves, the sedum allows the temperature to drop through the phenomenon of evapotranspiration (rejection of water into the air by transpiration). The energy savings are estimated at 20%.
What About the Maintenance of a Sedum Green Roof?
Maintaining a green roof is essential to preserve its aesthetic appearance and waterproofing. But as the sedum roof is very resistant, it requires little maintenance, 1 to 4 times a year. However, the intervention must conform to the specific technical reference documents (DTRS).
To preserve its vegetation, a sedum roof requires a minimal irrigation system. The maintenance operations thus consist in checking the automatic watering system. Like removing moss from a conventional roof, weeding a sedum roof is also essential to avoid the proliferation of certain weeds, even invasive plants.
For the waterproofing, an annual control must be carried out to inspect the structure, clean the drainage elements, and repair any damage.
Other Options Besides Sedum for Roof Greening
A green roof offers many options for customization. There are many combinations to add a personal decorative touch to work. If the sedum is used as the main cover, other species of plants can be added, such as perennials. Just play with the varieties for flowering in any season.
For a semi-intensive green roof, shrubs and grass will complement the sedum. However, a slightly thicker substrate of 15 to 30 cm is required.
It is also possible to create a garden with trees and shrubs on the roof for intensive greening. This requires a substrate of 30 cm and more and a quasi-flat structure or a slope of 5° or less. Its implementation is much more complex and expensive than the extensive green roof.
