One of the most common types of sloped-roof covering in the United States and Canada is asphalt shingles. Asphalt shingles have a service life from 20 to 40 years, depending on the shingle quality, installation, and maintenance.
When they begin to lose their granular covering and start to deteriorate, crack, or curl, the shingles should be replaced. In the inspection image, the edges of the older shingles are starting to curl slightly.
No more than two layers of asphalt shingles should be installed on a deck of a house roof structure at any one time. The inspector is checking the layers in the inspection image.
If the second layer of asphalt shingles has been applied, the inspector could check to see if all the flashing materials of the first layer were reinstalled with the new second layer. In the inspection image, the inspector is checking the roof-to-wall flashing and observing properly installed step flashing.