The design of the roof gardens is dictated more by the roof structure and its ability to support loads than the application of stylistic concepts.

We must also take into account issues such as private property and safety, as well as the position of any facilities (air conditioners, ventilation fans or skylights).

The hanging gardens designed together with the rest of the house will be less problematic; on the contrary, converting an existing roof can be very expensive and complicated. The first problem to be solved after structural issues is exposure.

The roofs are difficult environments, susceptible to strong fluctuations in temperature, much less repaired than traditional gardens and devoid of soil to be excavated for planting the plants. Shields of fabric, glass or wood protect from the wind; grilled or perforated panels reduce speed instead.

All fixing systems must be robust and resistant, to avoid damage or loss of parts. Select suitable plants to cope with difficult climatic conditions, and instead of using small containers take into account – weight permitting – largely raised flowerbeds, because in the former the soil will dry faster.

Drainage must be carefully designed to guarantee a fast and efficient water flow; you must also pay close attention not to damage the waterproof roof cover.

Finally, do not forget all the practical issues related to the transport of materials and plants.

Read also: Garden project: garden on the roof