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The technical side of green renovation: flat roofs
Sedum and extensive green roofs are so intertwined that in practice people often talk about Sedum roofs. Why is that? What is Sedum and what makes Sedum so suitable for extensive green roofs?
The natural properties of Sedum make this succulent plant extremely suitable for roof greening. Sedum – also often known as stonecrop – is a genus of the Crassulaceae family of succulent plants. This family consists of four to five hundred species and thousands of different varieties. Succulents are plants that store water in a part of the plant. Sedum stores water in the leaves, and this is why Sedum is often referred to as a leaf succulent.
The metabolism of Sedum differs from other plants. At night, carbon dioxide is absorbed through the stomata and converted into malic acid. During the day, under the influence of sunlight, the malic acid is decomposed and photosynthesis takes place. The stomata in the leaves are only open at night. During the hot and dry day, moisture loss is minimized.
Many Sedum species originate from the northern hemisphere and around the Mediterranean in particular. However, Sedum can also be found in North Africa and South America in dry and/or cold areas where water may be scarce. Thanks to its natural properties, Sedum requires little maintenance in green roofs: it requires little (rain) water and nutrients.
Green roofs with Sedum
An extensive green roof or Sedum roof is a roof with vegetation that is more or less self-perpetuating and that can further develop and maintain itself. Roughly speaking, extensive green roofs have a substrate thickness of between 4 and 15 cm and a weight of 45 to 220 kilo per m2.
When Sedum vegetation is applied to a green roof, the weight is approximately 45 kg/m2. When using a biodiverse vegetation – such as a mix of sedums, grasses, herbs, plants and nectar plants – the weight of the green roof is about 150 kilos/m2, because a thicker substrate layer is required. Sedum roof greening
Making your roof more sustainable with Sedum is – in contrast to intensive green roofs – a low-maintenance and cost-saving greening method. By applying Sedum mats instead of loose Sedum plants, installation is very simple and this saves you a huge amount of time. In addition, the maintenance costs are much lower, because the Sedum-mix mats already have a good rooting and require much less water after installation, than with loosely planted plants.
Sedum roof
Sempergreen conducts on-going research into the quality of Sedums and other plants for extensive green roofs. Thanks to the many years’ experience, Sempergreen has gathered much knowledge and expertise about Sedum varieties and other plant species. By no means are all Sedum varieties suitable for use on extensive green roofs or in a Sedum vegetation blanket. For instance, tall or large-leaved Sedum varieties are less suitable, because the plants may break or become damaged when the mat is rolled up or laid out. Sempergreen selects only the most suitable Sedum varieties for cultivating the various vegetation blankets. So you can be confident that your green roof really will remain green all year round. Naturally!
Ready to make a difference? At Sempergreen, we believe in building a greener future, one step at a time. Our innovative solutions are designed to help you decrease your footprint and contribute to a more sustainable world. Join us in replanting the planet!