A roof ventilation apparatus for a sloped roof having a cap and base plate is provided. The cap has a top surface and a bottom surface. The bottom surface has a flange that defines an opening to a cavity formed between the top and bottom cap surface. The cavity provides a path for air exchange from a roof opening through an air passage formed between the flange and cap top. The base plate has a collar or curb surrounding an aperture that fits inside the cap bottom cavity. The base plate preferably is shaped such that when installed on the sloped roof the cap entirely covers the base plate. Preferably, the base plate includes a collar and an angled edge configured to channel moisture that seeps within the vent cap.