Structural Requirements: Falls and Drainage

Sedum plants hate having their roots in water and so good drainage is of the utmost importance.

A living roof needs a minimal fall (or cross-fall) of 1 in 60 ie a 1 degree fall. Click here for diagram.
If the roof slope is less than 3 degrees, then a layer of drainage mat needs to be incorporated into the roof build-up.
Roof falls and the positioning of drainage outlets needs careful thought - standing water must be avoided at all costs. Click here for diagrams.
Maximum recommended fall is 25 degrees
Irrigation is essential for falls over 10 degrees - for small areas a hose or a sprinkler is fine.
If the roof slope is over 9 degrees, we recommend using 1m x 1m slabs of Enviromat. Larger pieces will be more prone to slippage.
Avoid or re-direct water discharged from high level roof areas to prevent over saturation and substrate erosion.

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