Plumbing vent flashing

Can someone provide me with a link or info on why caulking the bottom edge of a plumbing vent flashing is not recommended.

Thanks in advance!


OK. I’ll try another. Comments on this flashing installation. Would you call it out not being under additional 2 courses and bottom edge being sealed?

Improperly installed roof flashing using [size=2]fabricated asphalt roofing materials. [size=2]Asphalt roofing material tends to break off or deteriorate rapidly when used in this application. Unfortunately, flashing of this type is routinely approved by local building authorities and may be considered a local building practice. Recommendation: Evaluation and replacement by a licensed roofing contractor.




Looks like it’s nailed down at the bottom. Someone put mastic there for “extra protection” and I don’t see anything wrong with it. Water isn’t supposed to get underneath the flashing anyway, so there is not a valid argument for leaving it open to drain. I prefer to see the shingles overlap past the roof penetration like Mr. Currins example. It’s just a judgment call. If it’s not leaking, I probably would not recommend that it be replaced. You’ll see much worse. I see mastic like that a lot.

Well said Joe, no big deal.
Glad to see your using your common sense :p:p:mrgreen:

Until the asphalt flashing starts cracking, which in Ohio, will be in 2 or 3 years, allowing water from rain, snow, and ice to penetrate.

It had a regular plastic/rubber flashing around the pipe that wasn’t cracked. The just dressed it up with mastic for “extra protection”. I see that all the time.