About green roofs and checklists.
- It is always the responsibility of the developer’s advisors and the supplier of the green roofing, to ensure the underlay is properly designed and constructed concerning the chosen vegetation type. The developer’s counsel and the provider are equally responsible for the description of the D&V on the green roofs.
- The roof membranes must be of high quality.
Roofing heights along adjacent buildings must be adequate, i.e. 150mm above the surface of the ceiling covering.
- All coverings must be of stainless steel.
- Avoid using organic materials, as just a few leaks will reduce the roof’s lifespan.
- The membranes must be able to withstand the micro bacterial environment which occurs in the soil. The loss of plasticizers in PVC-containing films as a result of the terrestrial environment can cause stiffness and crack in the membrane. There are PVC foils available with additives that prevent the breakdown of plasticizers on green roofs. Contact the manufacturers for more information.
- Ensure that the coating does not freeze to the membrane, to ensure the membrane does not rupture due to temperature fluctuations. Freezing and cracks caused by mechanical movements can avoid by installing a sliding foil of HDPE and a nonwoven, or, on intensive green roofs, installing a minimum of 50mm of expanded polystyrene.
- Deformation: It is important when designing a green roof that your calculations take into account the differential movements. A green roof can weigh between 50 to 120kg per m2, so this permanent load must be placed on the roof before you start installing partition walls. That reduces the movements which telescopic solutions should be able to record.