A construction system for releasing moisture from a building is provided. The system is especially suitable for use in buildings having a hip, valley or gable roof. More specifically, the device gives the hip, valley or gable roof adequate ventilation and moisture vapor release portals so as to allow air and water vapor to properly rise through the interior of the hip, valley or gable roof and out through ridge vents without becoming trapped by rafters of the hip, valley or gable roof. The system has a first unit and a second unit, wherein the first unit allows air and water vapor to pass through passageways of the first unit up through the underside of the hip, valley or gable roof up and out through the ridge vent(s) and the second unit allows air from the exterior to pass into the roof cavity to circulate through the roof cavity and into the first unit.