The primary thing inspectors look for during a roofing inspection is damage. In addition to damage to the exterior of the roof, an inspector sometimes conducts a walk-through of the home, looking for damage to the walls and ceilings.
Common problems found on the exterior of the roof include cracked caulk, rust spots on flashing (the thin pieces of weatherproofed material in joints), broken, curled or missing shingles, and cracked and worn rubber around vent pipes. Large masses of moss and lichen are also a concern, as they may signal structural decay in the roof beneath them. Black mold on the exterior of a roof is generally only a cosmetic concern, as long as the roof remains impervious to mold and other biological material. Other potential problems include the wearing off of the colored grit from asphalt roof tiles; that can mean the tiles have lost their protections against ultraviolet light, meaning they are nearing the end of their effective lives. Inspectors also look for dry rot and other issues with wooden components.
On his inspection of the interior of the home, the home inspector looks for evidence of wind and water damage, as well as issues with the drywall.