What to look for in a roofing contractor: Roofs to a lot more than just keep out the rain. They also can prevent heat build up in summer, keep rain off the walls of the house, and affect the curb-appeal of the home. Just like most other parts of your home, your roof is not a stand-alone component; it interacts and affects other parts of your home. Make sure you ask about how your new roof will provide adequate ventilation for your attic space, whether your roof should use metal valley flashing, and whether a drip-edge flashing will be used where shingles overhang your roof.