Roof gardens planned around what the slab can carry and where the water goes, before anything is planted.
Two things decide whether a roof garden works, and neither is planting. The first is load: saturated soil weighs far more than dry soil, and a slab designed for foot traffic was not designed for beds. The second is waterproofing, because a leak found later is found through the ceiling below.
How we approach it
- Load checked against the structural drawings, with the engineer where there is any doubt
- Waterproofing and a root barrier laid and tested before soil goes down
- Lightweight growing medium, not garden soil carried up in sacks
- Drainage layer and outlets sized for monsoon rain, not average rain
- Planting chosen for wind and full sun, which a roof has more of than a garden
Common on Dhaka apartment blocks and offices, where the roof is often the only open ground a building has.
