Now celebrating its 3rd year, World Green Roof Day will be held on June 6 this year.
Green roofs don’t need to be on large commercial building rooftops, they can also be used on smaller roof spaces such as home offices, garden sheds, bike sheds and bin stores.
Green roofs are proven to provide practical benefits such as:
- improving air quality
- cooling urban environments
- managing heavy rainfall
- insulating buildings
- by boosting the mental well-being of those looking out on to them
They also aid biodiversity. They are perfect for attracting birds and other wildlife, creating thriving habitats. A study of green rooftops in London recorded more than 20 species of bees foraging on them.
A green roof can help to blend a building or structure into its surroundings.
They do tend to be more expensive than traditional options. One significant reason for this being the extra structural support required to handle the increased load on a roof. Having said this, a green roof that has been properly installed and maintained should extend the lifespan of a roof 2-3 times its normal life.
If your roof has a slope of more than 20 degrees, it is better to divide the area up into multiple compartments to stop the growing medium from slipping off. Slopes any greater than 30 degrees are generally unsuitable for green roofs.
Green roofs are made up of several layers. Firstly, create a frame around the perimeter area of your roof. A waterproof/root barrier layer is then needed to protect the roof from any water damage. Follow this with a drainage layer, a water retention mat, then the growing medium. Use a multipurpose compost mixed with perlite as this will help improve drainage and save on weight.
Now it’s time for the plants. For a lower maintenance green roof, a carpet of sedums can be a good choice. They are incredibly tough and drought-resistant. They will still need watering, especially in prolonged hot weather, to establish properly. You can buy ready to roll carpets of sedum, but you can also have fun by creating your own by using plug plants.
Setting up a green roof is well worth the initial investment of time and money. Once filled out it can be a thing of beauty and somewhere for wildlife to hang out. You’ll have done a bit more for the environment!