Can I permanently seal over the roof plumbing vent?

[switchfan]

Unusual question here - I have an old travel trailer that's already half gutted, and we want to turn it into extra office/classroom space for our homeschool family. It's going to be up on blocks in our yard and immobile. We plan to take out the bathroom and kitchen bits entirely. But first I have to replace all the roof vents and reseal everything (the vents are all leaking because the lap seal is old and cracking). Can I just take off the plumbing vent caps, cut the plumbing pipes flush with the roof, and put eternabond tape over it? Is there any reason I need to sink new caps and time on repairing and sealing those openings when they won't be used at all? I'm a complete newbie to renovations, so I want to make sure I'm not missing something.

 

[NY_Dutch]

With no plumbing to vent, there's no need for the vent pipe or cap. Seal them in whatever manner works best for you.

 

[Rene T]

Yes you can remove them and cover the holes with tape. The only thing I would add to give the tape a little support is put a thin piece of sheet metal over the hole before I tape over it. It can be 1/4” in bigger.
I would not remove the 14” X 14” ceiling vents. I’d keep those for ventilation

 

[John From Detroit]

So long as you have removed the plumbing. No need for the vents.

 

[Rob&Deryl]

Except… there may be an attic vent to let out moisture from the area between the ceiling and the roof. My trailer has one. Check if yours does too.

 

[Martian]

The OP considers it an " old" trailer and that would lead me to think it was built more than ten years ago as a guess. Very few trailers had vents for what might be considered the attic back then. Some higher end units did and the better units usually do not get to the point where they need to be gutted. Not knowing what it is/was makes it a guess.

 

[Rene T]

The OP considers it an " old" trailer and that would lead me to think it was built more than ten years ago as a guess. Very few trailers had vents for what might be considered the attic back then. Some higher end units did and the better units usually do not get to the point where they need to be gutted. Not knowing what it is/was makes it a guess.

It’s easy enough to figure out? Remove the end cap and look down the pipe. If it’s 2” long, it’s a attic vent. If you can’t see the end of the pipe then it’s a tank vent.

 

[Punomatic]

I would make sure the tanks are empty and clean before sealing the vent. A little sunshine heating up the "schoolhouse" could cause any "questionable" matter to emit gases though the vent pipe into the space between the cut end of the pipe and the roof patch. Or cap the pipe before patching the roof.