Abstract: A ventilator having a one-piece plastic base with integral tubular member having a through passageway for flow of an exhaust gas stream. The tubular member is preferably molded simultaneously with the base, rather than glued, so that the base and tubular member assembly comprise not only a sealed tubular member, but provide a single, seamless part. Thus, moist air cannot leak out of the air flow path between the interior and exterior of a wall or roof. The ventilator is also provided with a screen and a flapper type lid for the tubular member. The flapper lid seals the outer end of the tubular member against inflow of outside air at those times when there is no exhaust gas stream impinging against the flapper so as to keep the flapper in the open position. The ventilator may be provided in a variety of colors by pigmentation of the plastic to be molded into the ventilator.

Abstract: A one piece molded plastic foundation ventilator. The ventilator includes a one-piece continuous and structurally jointless plastic tubular member having a first through passageway, with the tubular member having a front and a rear, and with the through passageway of the ventilator including a portion between the front and the rear having a smaller cross-sectional dimension than the front, and having a smaller cross-sectional dimension than the rear. The front and rear of the ventilator includes outwardly directed flange portions. The ventilator may be supplemented by the addition of a screen and a hinged cover with securing latches.