Removing and patching no-longer-used roof vent

[dalepres]

We just had our mobile home furnace replaced with an all-in-one outdoor ac/heater unit. The contractor took out the old furnace and covered the connection to the duct underneath but left the roof vent.

I am thinking of just using a jig saw to remove the vent and screwing down a piece of suitable metal with plenty of sealant under and over the edges. I don't know what kind of sealant to use but I'm thinking about using that stuff they advertise on TV where they use it to seal a window screen into the bottom of a boat and the boat floats.

Before I make a mess that is difficult to clean up to do right, I figured I should ask here for suggestions and to make sure I am approaching this correctly.

So, suggestions?

Thanks,

Dale

[Greg]

I would stay away from the "Wonder sprays" and go with a tried & true sealer. an elastromeric sealer or Black Jack. The last thing you need is a roof leak.

Greg

[countrydan]

I would cap the ouside end with a galvanized metal cap and use self tappers/sealant if it needed to be closed off. Then check the vent's "boot" while up there and repair/ patch as needed with proper roof tar patch. Then insulate and or close the opening from below.

Then when I replaced the roof I might close up the opening if I wasn't ever gonna need it again.


And as Greg, i do not recommend using the tv stuff. Use contractor grade materials that will last.

[dalepres]

Thanks for the replies. Just sealing the vent is not really an option because they hacked up the pipe coming into what is now a new closet. It's got multiple sharp points and edges on the inner and outer tubes and sticks down into the space too far to ignore. Had they cut it into the "attic" space I might have just left it. The easiest and safest thing now is going to be just cut the entire thing out.

I was trying to figure out where to get some galvanized sheet metal for the patch but it finally hit me that the AC guy should have that.