In this residential project in Higgovale, tucked away in Cape Town city bowl, our client opted for Drainroof for the creation of an extensive roof garden (90 square metres), built over a concrete roof slab, previously waterproofed.
Drainroof is Geoplast's solution for roof gardens; manufactured in recycled polypropylene, the interlocking panels create a ventilated gardens that protect the waterproofing while offering high rainwater storage in the formwork feet. It can in fact accumulate up to up to 20 litres/sqm to irrigate the surface plants and lawn.
The light elements have a dome structure that separates the slab from the garden, ensuring ventilation and therefore eliminating any possible water stagnation. The design makes provision for water drainage, as the perforated structure and channels allow for fast disposal of water.
Since the roof slab was already waterproofed, installation simply required laying the interlocking panels and cover them with expanded clay beads (leca) for high water absorption capacity. Geo-textile was then added between the filling material and the sub-layer, as a filter for the water of dissolved particles. The sub-layer was then added on the surface.
The formwork ensured a fantastic final result, without damaging the roof structure and while ensuring the sustainability of the garden.