Flashing roof penetrations on low slope roofs

I have searched through code books and installation manuals of multiple roof covering manufacturers and have found absolutely no literature on how roof penetrations (plumbing vents & mechanical vents) should be flashed on low slope roofs with roll roofing or similar materials. Haven’t found anything in InterNACHI’s articles either. I even called GAF and Owens Corning and they told me they didn’t know. Is this just a grey “do what you want” area or what? Any info or a point in the write direction would be appreciated.

I saw that. Means nothing though. I’m looking for literature and requirements. Not how some random guy flashed a penetration and made it work.

Most flat roofs are on commercial buildings. You won’t find what you want if you’re looking up shingle installation. Nor will you find it in code. Code just calls for flashing… as prescribed per engineer or manufacturer of the roofing system being installed. There are many ways of flashing penetrations on a flat roof, you just need to understand the overall idea of how it should be done. Here are a few methods, prescribed by EPDM manufacturer:

Anything more specific other than what can be found here?


Am I missing the flashing for b vents? I don’t see it

Give this a try. Used to go here to get details when doing commercial consulting. Didn’t have time to look for the right detail though. https://soprema.us/documents/installation-instructions