BMDesign Studios

The Concave Roof System by BMDesign Studios Seeks to Optimise Rainwater Harversting

Iran-based BMDesign Studios has unveiled Concave Roof, a double-roof system with steep slopes resembling a bowl for the purpose of rainwater collection in arid climates like Iran, where a lack of water could lead to mass displacement in the future.

Because precipitation in this area is less than one-third of that of the world average, and evaporation is more than three times higher than the world average. The outer shell of the roof system not only collects rainwater but also provides additional shading and allows air to move freely between it and the inner shell, acting as a cooling mechanism for both roofs.

“The concave roof system is designed to help make even the smallest quantities of rain flow down the roof and eventually coalesce into bigger drops, just right for harvesting before they evaporate”

-BMDesign Studios

At a school with 923 sqm of concave roof area, it is expected that 28 cubic meters of water could be collected, with an efficiency of about 60 percent. Further research for the system will focus on maximizing this efficiency. Reservoirs connecting to the collection systems will be placed between building walls, allowing for further control of temperature fluctuation of indoor spaces due to the heat storage capacity of water, all of which will lower the overall carbon footprint of much-needed air conditioning in this harsh environment.


  • Architects: BMDesign Studios
  • Location: Jiroft, Kerman province, Iran
  • Architect in Charge: Babak Mostofi Sadri
  • Design Development: Dena Bakhtiari
  • Design Team: Babak M Sadri, Dena Bakhtiari, Nazanin Esfahanian, Negar Naghibsadat
  • Structural Engineer: Sina Rostami
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