Recommended Weight Allowances for a Sustainable and Bio-diverse Living Roof.
 

At Oxford Green Roofs Ltd we always follow the Green Roof Code of Best Practice (click on green button to view) which gives a clear indication and explanation of depth of substrate required for a fully sustainable and bio-diverse green roof. Over the years we have gained experience in the best depths that support a variety of planting schemes and our advised weights are a result of this experience. 
 

The following are the minimum weight allowances.

Sedum – 130kg/m2

Wildflower meadow – 180kg/m2
A roof with extra aggregate and wildlife habitat - 250kg/m2
 
To be honest if you are unsure what kind of planting you would like then allowing for 200kg/m2 will give a considerable amount of choice.