Structural Requirements: Loading

Sedum Blanket finish on a new or existing domestic property will weigh between 65Kg/m2 and 150Kg/m2. It is vital that the building is able to support this weight as well as any live loading (snow, people accessing the roof for maintenance etc).

  • Before starting a green roofing project, it's wise to consult an Architect or Structural Engineer, especially for domestic properties that need insurance.
  • Calculations must take account of all anticipated weight loads.
  • Existing structures may need to be reinforced to take the extra load.
  • Support joists must not be too far apart otherwise deck deflection might lead to standing water on the roof. Standing water means more weight on the roof and is likely to damage the sedum plants.
  • Be aware that existing metal decked roofs will deflect under the extra loading and this may cause ponding.
  • Building Control may need to be consulted if the new roof is on a shared boundary with a neighbouring property (fire regulations).
  • For green roofing projects larger than 50 square metres, please contact us.