so anyway this has been bugging me since last week. did a residential roof inspection for an insurance company, pretty standard stuff, hip roof maybe 2500 sq ft, used the phantom 4 pro like i always do. went through my usual grid pattern, got good overlap, imagery looked clean on the controller screen. sent the report and then the adjuster goes out there with an actual roofer and they found a pretty significant section of lifted flashing around the chimney base that i completely missed.

went back and looked at my footage frame by frame and you can kind of see it if you know what youre looking for but its not obvious at all because of the angle the sun was hitting that face of the chimney. the shadow basically ate the detail. im not trying to make excuses but i also want to figure out how to not have this happen again. do people fly these things twice at different times of day or is there some other approach im not thinking of. thermal seems overkill for roofing but maybe im wrong about that

thermal is actually not overkill at all for roofing, thats kind of its bread and butter. lifted flashing and moisture intrusion both show up really well on thermal especially if you fly in the evening after the roof has been absorbing heat all day and starts cooling - the wet or lifted sections retain heat differently and it pops right out. a lot of guys doing insurance work have started doing a quick thermal pass as standard even on jobs where nobody asked for it just because it covers them exactly for situations like yours.

the sun angle thing is real though even without thermal. i try to plan my flight direction so the sun is more or less behind me relative to the critical faces, its not always possible but it helps. also slowing down and getting a bit lower than you might think necessary around transitions like chimneys and valleys makes a big difference for detail.

yeah shadow is a killer on roofs, ive had similar issues with north-facing dormers especially in the morning. i dont do thermal yet but ive been considering the M3T just for this reason. the flashing around penetrations is always going to be the weak spot for visual-only inspection i think, theres no angle thats perfect for all of them in one pass. some guys i know do a separate low slow orbit just around the chimney and any skylights at like 15ft AGL which sounds tedious but probably worth it on larger or more complex roofs