Green Roofs

A green roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. Green roofs serve several purposes for a building, such as absorbing rainwater, providing insulation, creating a habitat for wildlife, and helping to lower urban air temperatures. Many sedum species are available which flower and provide an attractive roof covering.

Components of a green roof are:

• Timber Frame – holds the green roof elements onto the roof. Extra timber supports may be needed to ensure that the building can take the load.
• Root Membrane – damp-proof membrane.
• Filter Sheet – this stops fine material from leaving the roof. It holds the fine soils but allows water to pass through.
• Moisture Blanket – a geotextile membranes which holds moisture.
• Substrate – this is the medium in which the plants will grow and should consist of aggregate such as crushed concrete/brick, limestone chippings, gravels or clay pellets. This should be at the base to free drainage. Finally, the top layer consists of sand or soil
• Plants – the species selected will depend on the substrate and the substrate depth. They can be seeded or plug planted.