Gas Water heater vent question

Hi all-

I’m still new to this business so there are things I haven’t seen yet.

This is the gas vent from a water heater in the garage. I thought the ceiling damage was due to moisture intrusion but I can’t find anything that looks like water damage on the ceiling or in the attic. Would this be caused by the vent not having any gap between it and the drywall ceiling?


Do you have a pic of the storm collarup on the roof? Needs a thimble and/or 1" clearance at the ceiling regardless.

That looks like moisture damage, so check the attic for condensation and like Mr.Frederick says, the chimney storm collar, roof jack and caulking. B vent should be mounted through a UL/CSA approved fire stop where it penetrates the ceiling.