Abstract: In accordance with the present invention, there is provided a new and inexpensive ventilating system for greenhouses using rigid plastic, glazing panels that are thin, lightweight, and quite long. This is achieved by bending outer ends of the glazing panels and lifting to create vent openings. This method takes advantage of the inherent flexibility of these glazing panels to bend them to shift between open and closed positions without the use of a conventional, separate hinged, framework section. Particularly, in accordance with the present invention, an actuator is connected to a flexible bendable portion of the elongated, rigid glazing panel and the actuator lifts and bends an end portion of the panel, which has an inherent flexibility unlike glass or thin films and which has a memory and an elasticity, such that the panel wants to return to its normal unflexed position, which is the closed position, in the preferred embodiment of the invention.

Abstract: An existing glazing system using small rectangular plastic or glass glazing panels or using thin films, plastic glazing panels may be converted in an inexpensive manner to an elongated rigid, plastic glazing panel system having a condensate removal system. Very long glazing panels of plastic, preferably corrugated, are laid across several purlins in the vertical direction. The glass glazing panels or the thin film glazing panels are removed to expose the roof members. Purlins are laid across the roof members with ends of the purlins positioned intermediately adjacent roof rafters. Condensate collector channels on the purlins convey moisture to the ends of the purlins and discharge collected moisture to an underlying drain, which is fastened to and carried by the purlins. The drain is spaced from the rafter roof members. Very long glazing panels of plastic, preferably corrugated, are laid across several purlins in the vertical direction.

Abstract: An existing glazing system using small rectangular plastic or glass glazing panels or using thin films, plastic glazing panels may be converted in an inexpensive manner to an elongated rigid, plastic glazing panel system having a condensate removal system. Very long glazing panels of plastic, preferably corrugated, are laid across several purlins in the vertical direction. The glass glazing panels or the thin film glazing panels are removed to expose the roof members. Purlins are laid across the roof members with ends of the purlins positioned intermediately adjacent roof rafters. Condensate collector channels on the purlins convey moisture to the ends of the purlins and discharge collected moisture to an underlying drain, which is fastened to and carried by the purlins. The drain is spaced from the rafter roof members. Very long glazing panels of plastic, preferably corrugated, are laid across several purlins in the vertical direction.