Pitched green roofs

Engineering challenge

Organic Roofs’ first pitched green roof was the Boathouse at Avon Tyrell by HPW Architects. The plans called for the roof to almost appear to float, and so the project saw us work with waterproofing partners Hertalan to co-develop an innovative anti-shear system enabled us to secure the growing medium and plants on the roof while preserving the aesthetics of the building. You can read more about this method of retaining substrate here. We have since

Beyond flat roofs

Since working on this project we have developed beyond our ShearStop design and undertaken multiple pitched green roof projects, successfully achieving up to 45 degree sustainable growth without penetration of the membrane. Our project overlooking a fishing lake near Milton Keynes was featured on the Channel 4 Sarah Beeny property programme. If you are thinking about adding a pitched green roof, consider signing up for detailed project-specific support call – our Project Surgery service – from which you’ll take away all the information you need to go to tender confidently.

Design considerations

Achieving viable growth on a pitched green roof is possible, and the results can be fantastic but there are a few things that need to be considered before its attempted:

• Additional cost: the measures to keep vegetation in place require more engineering and labour time on site
• Irrigation: pitched roofs should have a permanent irrigation system in place
• Moisture-retention: because pitched green roofs are very free draining we recommend a thicker moisture retention product is used underneath the growing medium