Roof Shape: Flat or Pitched Roof?
Roof Material: Typically Metal Roof/Roman Tile roof/Shingle Roof or other standing seam roof. How well is the roof material attached to the underlying layers?
Roof Strength: is it safe to mount solar panels to its roof?
Roof Rack: Can you add a suitable roof mounting system mount solar panels on roof.Stainless steel roof hooks are proposed for various tile roof.L brackets are proposed for metal roof.Flashing plate are proposed for shingle roof solar structures.Aluminum roof clamps are proposed for standing seam roof.
Solar Panel Cleaning: Is it easy to reach the roof? If not, do you have a way to clean the solar panels when necessary?
Solar Panel Strength: If you are using large panels, you will need to mount it more securely so that it doesn't twist/flex and ultimately crack. If you plan to use large panels (anything larger than 200 watts), you may need to mount the solar panel to a frame so it doesn't twist/flex, or over-engineer some traditional mounting methods so that it stays put.