The growing interest in green roofs is not only due to the visual esthetical pleasure. Green roofs serve several purposes for a building, such as absorbing rain water, providing insulation, creating a habitat for wildlife, and helping to lower urban air temperatures.
Retaining water from severe rainfall can help relieve and prevent a sewerage system overload. The problems with heavy rainfalls have increased and are not expected to diminish in the future.
Constructing a green roof may seem easy, but there is more to it than just rolling turf on the roof. A wide range of aspects must be considered. Foremost the roof should be constructed to bear the weight of the grass and the growth layer - when wet it can be several tons. Drainage, humidity, roof sealing, insulation, condensation, membranes and waterproofing are other issues to be considered. Get professionals to calculate on the specific project in order to avoid unpleasant and dangerous surprises.
The growth layer is a prerequisite for the roof to remain green and not become brown and withered - and therefore flammable! If the composition is wrong or too thin, it quickly dries out and the grasses and other plants are unable to survive. As a minimum there should be a growth layer of 15 cm. The finishing touches of a green roof are the choice of plant species.
There are many possibilities, but a common feature of the species suitable for green roofs is their drought tolerance. Within grasses especially different types of fescues are interesting. Red Fescue, Sheep's Fescue and Hard Fescue are particularly suitable because of their modest demands for fertiliser and especially water. However, if you choose to use turf, a variety mixture of Red Fescue is recommended. DLF‐TRIFOLIUM will help you put together the right species that are suitable and most optimal for your project. When properly designed right from the start, the green roof is to the benefit of both humans and the environment for years to come.