On One Hand: Contractor InspectorA new roof should be inspected by a representative of the roofing contractor. The representative will inspect the roof as a quality control measure for the contractor and to make sure of compliance with all codes from the local government that issued the building permit. Any potential substandard work or building code violations found will be corrected.
On the Other: Building Inspector and Third PartiesThe new roof should also be inspected by a building inspector from the local government that issued the building permit to ensure code compliance. The owners/buyers may also want to hire a third-party inspector for an unbiased professional inspection and their own peace of mind.
Bottom LineA new roof should be inspected by the contractor's quality control inspector prior to any other inspections. This will give the contractor an opportunity to correct any substandard work before inspection by the local government building inspector.
Source:Foof Coop: Roof Inspections
Foof Coop: Inspection FAQs