Ventilation system for contoured roofs

A contoured roof ventilation system includes a support structure, with a vent opening through the support structure located along a ridge of the roof. A contoured roofing material is located on the support structure and defines a plurality of crests and valleys. First and second vent strips are located on opposite sides of the vent opening along the ridge, and have a first surface complementary to the crests and valleys of the contoured roofing material in an installed position, and a plurality of longitudinally extending slots that extend parallel to the ridge to define at least three spaced apart vent material ribbons, and a second surface. At least one water barrier is positioned above the second surfaces of the first and second vent strips and extends toward the ridge. Cap pieces having a lower surface that contacts the second surfaces of the first and second strips or the water barrier are located on the first and second strips.