The multi-layered system includes:
Filter geotextile – holds the growing media in place and only allows water to pass through.
Drainage cells – has a high crush rating to allow for foot traffic. Different cells are used depending on the design requirements, either assisting in flow rates or storing some water with a unique cup design.
Protection felt – although the Sarnafil® waterproofing has high puncture resistance and was designed to handle pooling water, another layer of geotextile is placed below the drainage cells for extra protection.
