A roofing system in a building structure having a ridge vent includes strips of composite material having a base material adapted to form a hermetic seal with the top surface of a roofing section and recesses in a top surface in which an air permeable material can be positioned. A strip is applied to roof sections adjacent to each side of a ridge vent so that a ridge cap can overlay the strips in spaced relation from the underlying roof sections and be sealingly secured to the roof sections. The strip material establishes a barrier between the ridge cap and the roof sections through which air can pass, but through which the passage of rain and insects is inhibited.