I have been using a temporary exhaust pipe and am ready to move to something better. I think I will take the 4" pipe up through the ceiling and out through the roof with a good amount of rise to it. Being in a neighborhood, I would like to do my best to blast the odors up and away from myself and neighbors. A typical roof vent would blow up and out under a cap to protect from rain, so the airflow is disrupted at that point and smell will stay closer. I want my pipe to blast wide open straight up to take full use of the velocity of air. So what are my options for such a thing? Do I top this off with a weighted flap that closes when off? Is PVC a better idea over metal? Is this just a bad idea? What is your opinion on placement of the blower; safely in reach or hidden up in the hot dusty attic closer to the outlet?
My roof is composition, not wood, so hot debris and sparks should not be an issue.