We usually prefer not to mount PV modules on roofs because of the potential for leaks, difficulty of maintenance and over heating, even though roof mount is generally more secure from theft or damage, and sometimes offers the best access to the sun.
Our preferred type of array mount is the Top-Of-Pole or side-of-pole rack. This type allows for easy seasonal adjustments for tilt angle, is easy to install, keeps us installers off of roofs (with the associated liability issues),and precludes roof penetrations (with the associated leak potential). As compared to ground mounts, a top-of-pole or side-of-pole rack puts panels up into a position less prone to damage from lawn mower,thrown rocks, etc.
Please contact us for project custom design.