How to lay sedum roofs

You can buy 'Green roof' sedum mats at these stores in Norway in 2025: Arendal, Bærum, Forus, Haugesund, Moum, Skedsmo, Tiller, Tromsø, and Åsane.

This article explains how to install a sedum roof, but sedum mats can also be used on slopes and similar areas. Read more about other applications in our plant guide for sedum and sedum mats.

Sedum offers a wide range of benefits, notably its ability to thrive in challenging environments where other plants struggle. These hardy, low-maintenance succulents are excellent for biodiversity, and they provide a beautiful, seasonally changing display of colors. When used on roofs, sedum offers these additional advantages:

• Effective rainwater absorption.
• Natural air purification.
• Provides insulation.
• Supports habitats for birds, butterflies, and insects.

The sedum mats in our stores consist of 12 different sedum varieties. Per square meter, 95 percent of the mats are covered with sedum. Other properties of the sedum mats:

• They do not shrink, so there are no gaps between the mats.
• They provide an immediately finished, covering result.
• Less weed growth, since they are finished mats that have been grown weed-free.
• They protect the substrate against wind and water erosion.

The size of one 'Green roof' sedum mat is 30x50 cm. The mats are placed close together, without overlap, and you can cut them to size with a knife. You need 6.6 mats per square meter.

During transport, the sedum mats are stacked on top of each other. Be sure to spread them out as soon as you get them home. Sedum needs light and air and must not be stacked on top of each other for extended periods.

1. Check that the roof is strong enough. A sedum roof is not much heavier than a roof with regular roof tiles.
2. Wash or brush the roof and let it dry.
3. Lay a root-resistant roofing membrane* on the roof – choose an approved high-quality membrane adapted to the roof angle. Consult a building materials store.
4. Cut a cross in the membrane where the rainwater drain should be.
5. Place a grating* in the drain to prevent it from clogging.
6. Lay coarse gravel around the rainwater drain.
7. For flat roofs: Lay out 3 cm of gravel or other lightweight granules* evenly distributed on the membrane. This functions as drainage and ensures that the sedum mats do not become too wet.
   For sloping roofs: Skip to point 8; the mats can be laid directly on the sloping roof.
8. Lay the sedum mats edge to edge on the roof, close to each other. The mats can be cut to size with a utility knife.
9. Water the sedum mats after the roof is finished, so they take root and start growing.
10. For the first 2 to 3 weeks, you should water daily if the weather is dry and hot (20 degrees or warmer).

*purchased at building materials stores

One of the advantages of sedum roofs is that they require little maintenance after the plants have established themselves. To keep the roof looking good over time, it's wise to follow these tips:

• Remove weeds and seedlings from trees twice a year. At the same time, check the gravel edges and remove ingrown sedum and weeds there as well.
• Clean and clear the drain so that it doesn't become clogged.
• Remove withered flowers in the summer to prevent the sedum plants from being smothered.

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