Structural loadings
The structural loading of a living roof needs to be considered at the design stage. Worth noting is that many flat roof structures with ballast or paving slabs, may be able to be replaced with an extensive green roof system with no structural loading implications. The following table details the saturated weights of different green roofs and landscape elements:
Indicative Structural Loading for Various Types of Roof
|
Roof type |
Loading |
| Gravel surface |
90-150 kg/m2 |
| Paving slabs | 160-220 kg/m2 |
| Vehicle surface | From 550 kg/m2 |
| Extensive green roof (sedum mat) |
60-150 kg/m2 |
| Extensive green roof (substrate based) | 80-150 kg/m2 |
| Intensive green roof |
200-500 kg/m2 |
| Note: loads are fully saturated |
Source: Living Roofs and Walls, Technical Report: Supporting London Plan Policy,
Greater London Authority, 2008
