Abstract: Improvements in roof ventilators; improvements in gable type roofing ventilators of the type typically having a vertical stack or chimney with a screening canopy thereover; provision of a dead air space at the top of a stack or chimney underneath and within an overlying hoodlike canopy; provision of a reversing flow channel by association of two hoodlike canopies with a stack, one of the canopies also providing an air capture space or trap at the top of the stack.

Abstract: A new ventilator for spaces under slanted roofs or attics such as gable, hip and shed roof types; a ventilator using an elongate duct typically positioned between adjacent rafters under a roof, the duct inlet spaced downwardly somewhat from the ridge, the duct outlet discharging through an opening in the roof surface spaced further down from the ridge; the duct outlet configured to drain water from itself and the duct as well as protectable from winds, snow, hail, birds and the like. A like new ventilator useable under the roof panels of tanks and grain bins irrespective of the presence of rafters thereunder.