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As the focus on environmental sustainability increases, so does the demand for green roofs. Providing natural insulation, enhancing biodiversity and reducing air pollution are just some of the benefits for your self-build home. However, to make sure your green roof stands the test of time, there are several factors to consider, including the type of waterproofing, installation best practice and future maintenance.

Weigh up your green roof options

The climate, local Building Regulations and building type are just some of the factors that will affect the design of your green roof, including the types of plants and growing substrate. Understanding these elements from the outset is crucial as they will impact the roof build up as well as future maintenance.

If you would prefer a lower maintenance solution, then an extensive green roof would be more suitable. This option is the most common on flat roofs. The system tends to use sedum, groundcover and wildflower-type planting, making it lightweight with less aggressive root systems.

The alternative is an intensive green roof, including trees and shrubs. This is, however, a more complex option as the roof will require more irrigation, fertilisation and maintenance. As the weight will be much heavier, the roof structure must provide a greater level of support and additional protection for the waterproofing system.

Research the waterproofing system

There are different waterproofing systems suitable for a green roof and selecting the right one is essential. The membrane must be resistant to root penetration and strong enough to be walked over when maintenance is required.

The RubberGard EPDM and UltraPly TPO membranes, for example, have passed root penetration tests from the German Landscape Research, Development and Construction Society.

We advise using an EPDM single-ply membrane, which is 1.5mm thick and can be fully adhered to the substrate, providing a robust solution. An EPDM membrane that can be installed using large sheets will also limit the number of seams, reducing the risk of any water ingress.

Studies have shown that EPDM membranes can last for more than 50 years. Their flexibility can accommodate expansions or contractions due to …