Maintaining a Green Roof

Maintaining a Green Roof

Keep it happy and healthy

1st December 2014

Green roof maintenance is generally a very simple process. They are designed so that they will not require endless hours spent on your roof in order to keep them looking at their best.

As with all roofs, it is important that the drainage channels remain clear or they could get blocked, which can cause pooling and leaks in the roof, as well as kill the vegetation that is left in the pooling water. In order to make sure this does not happen, leaves or debris simply need to be cleared from drainage channels or gutters once or twice a year. This straightforward task does not differ from normal roof maintenance.

Further green roof maintenance processes differ depending on which system is being used on your roof.

Sedum green roofs require very little maintenance as they are very hardy plants and don’t require much attention to keep them healthy. A sedum green roof can be maintained easily in two visits, one in the spring and one in the autumn. In the spring, the gutters and drainage channels will be cleared, any weeds removed and fertiliser applied. In the autumn the drains can be checked again and the spent flower heads and any weeds that have grown over the summer can be removed. With this little maintenance Sedum will remain healthy and your green roof will stay looking lush throughout the year.

Other systems require slightly different maintenance. With wildflower roofs it is recommended that the year’s growth is strimmed and removed in the autumn, This prevents a build up of decaying organic matter on the roof and the nutrient levels do not get too high. Biodiverse roofs require little maintenance because they are designed to be seeded naturally by the local environment. Some people like to remove certain species from their biodiverse roof and others like to cut back the year’s growth in autumn but this is personal preference and is not essential for biodiverse roofs.

The only other form of maintenance green roofs need is irrigation. As green roofs only have a limited depth of substrate to reduce weight, moisture cannot be drawn up from deep in the ground like it can for conventional plants. That said, a good drainage board will allow the plants to absorb all the water they need to stay healthy using only natural precipitation. However, in the first few months after installation the plants will be ‘stressed’ from the move and will be trying to establish in a new environment. In this time, and in periods of extremely hot and dry weather, roofs may need irrigation in the form of full saturation once or twice a week.

Sedum is an extremely drought resistant plant and even when it looks like it has died from lack of water it is likely the underlying structure is still alive and therefore will continue to grow when it rains again.

If you have any questions about green roofs or maintenance of a green roof system, please do not hesitate to contact us.