Nothing strikes terror in the heart of a homeowner like the words “you need to replace your roof.” Fortunately, a good pre-purchase inspection usually covers the entire roof, and now home inspectors across the nation are leaving their ladders behind while they look for damage from a safe spot on the ground. Larger roofs on commercial buildings are easy to inspect with a drone as well, using the same automated mapping techniques you’d use to stitch together a ground survey. Even angled roofs can be dealt with easily as you construct a 3D model by making two successive passes, one with the camera straight down, another at an angle. These breathtakingly accurate measurements mean less waste in supplies, better documentation for records, and lower uncertainty for job costing and time estimation.