Originally Posted by
Kevin Barre
The flashing is fine at the roof; it's a soldered galvanized base similar to a plumbing roof jack. No problems there.
Are you sure? It looks like that vent just comes up out of the roof. I cannot imagine that is an approved flashing. I've seen the ones you are referring to, some are shown in the link Billy posted.
The Simpson info Billy posted (thanks, Billy) gives their blessing to a similar design. It shows the top of the B vent section ending about 1.5" to 3" above a base flashing. There is no base flashing in my example, but the overall concept is similar.
Actually, it is quite different.
Those made by Simpson in that link (and made by others as well) have ventilated sides. Those are 'high wind area' Type B Gas Vent Caps. The one in your photo is nothing like those - no ventilated sides, just a flat deflector above the vent opening with open top and bottom. Were you able to get on the roof? What did it say on the cap? All the approved Type B gas vent caps I've seen state Type B Gas Vent Cap on them.