Originally Posted by
Jerry Peck
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.
I could see the base of the flashing from inside the attic, and I could see it from outside using binoculars. It's a flat base flashing (made to the correct pitch) with the vertical section carefully soldered to it. While it obviously took a lot of time to make, I suspect it was made locally or may be old stock. That's why I had the questions. But it wasn't leaking, and it maintains plenty of clearance around combustibles.Those aren't concerns.
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.
As for getting on the roof, the roof pitch was a 9 in 12, and it had been raining. Much as I wanted to, I'm not crazy enough to get up on a roof in those conditions! My concern isn't the weather-tightness of the base, it's the rest of it.
Not that I'm doubting you if you've seen the "high wind area" type you describe, but in the Simpson info their wording does not mention any special high wind applications...they merely call the design a "combination" top. Simpson seems to tout it as an inexpensive method. In any case, their drawings clearly show the B vent terminating well below the cap. That's my real concern/question.
Not that is matters, but the local AHJ has passed it. I have no problem writing it up, but I want solid backing for my position to deflect the inevitable calls from the builder and/or HVAC contractor. I can't just say "I've never seen one like it on anything less that 30 years old."