Roof Garden Construction Layers and Green Roof Technical Essentials
A green roof is, first and foremost, a matter of structure and waterproofing. Get to know the essential layers of a roof garden.
Installing a roof garden without assessing the structure's load-bearing capacity carries significant risk. Calculations must account for the weight of the saturated growing medium, planters, paving and live loads.
The Layer Sequence
The usual sequence, from bottom to top, is waterproofing and root protection, a drainage layer, a geotextile filter, lightweight growing medium and, finally, vegetation and mulch. Omitting or repositioning any layer usually leads to waterproofing problems.
Plant Selection
On a roof, wind and sunlight are more intense than at ground level, and soil depth is limited. Ornamental grasses, hardy ground covers and undemanding species are the best choices.
