A vehicle includes a roof assembly including a roof having an outer facing surface and a roof ditch that extends below the outer facing surface. The roof ditch extends in a vehicle longitudinal direction between a front windshield and a rear window. A roof ditch sealer is located at least partially within the roof ditch. A mounting bracket for mounting a vehicle accessory is located in the roof ditch. The mounting bracket may include sealer dam portions that extend downward at opposite sides of a mounting surface of the mounting bracket to provide end stops for the roof ditch sealer.