[cgreenejunk]

I’m currently working on my own single-strapped metal standing seam roof that was overlaid on a pre-existing composite shingle roof.

Recent tree damage is triggering a repair with new metal panels, and I want to install a 7” diam (round) range hood exhaust through the roof while I’m at it.

I plan to use a flexible EPDM pipe boot where the pipe passes through the metal roof, but wondering what’s the best and proper way to flash and seal the pipe as it passes through the plywood/shingle roof underneath the metal one?

 

[OldNBroken]

no need.

 

[cgreenejunk]

no need.

I’d be concerned about any condensation that typically forms on the underside of the metal roof or on the surface of the shingles running down the vent pipe and through the gap between the pipe and the plywood sheeting of the shingle roof.

Also I’m not really keen to have free airflow (and insects) coming in to the attic space.

Other opinions?

 

[cgreenejunk]

Bump... looking for more input/opinions on this.

 

[OldNBroken]

Unless it is a bare galvanized panel,the condensation you are concerned about is not a "typical" condition. Even then not so much with a cold roof install. I guess you could try FlexSeal since the first answer wasn't what you wanted to hear.