On flat concrete rooftops, small raised turrets (stairwell or machine rooms) are often used to add photovoltaic capacity when the main roof is full. Installers frequently lay panels flat at 0 degrees on these turrets, fearing high wind catch. Yet flat mounting visibly cuts yield and worsens soiling.

On flat concrete rooftops, site survey quality directly determines PV layout, annual yield, and O&M safety. Field measurement exposes shading risks that satellite maps and drawings often miss. Among all collected data, the heights of five vertical obstacles must be recorded one by one: parapet walls