[JRTJH]

I agree with Chuck, this is one of those times when Eternabond tape is called for. It's used to cover holes and repair the OEM roof membrane, not to cover sealant to prevent leaks.

Make sure to prep the roof surface properly, install the tape and then roll it correctly to activate the adhesive so it will adhere properly.

On an "older motorhome" chances are very VERY good that the membrane is NOT TPO but rather is EPDM. While the process to install Eternabond is similar for both types of membrane, Eternabond used to recommend sealing all the edges of the tape with DICOR self leveling sealant to prevent the edges of the tape from "rolling up". With TPO roofing, that's not required and over the years, as the instructions were revised, with less and less EPDM in use, the comment to seal the edges "sort of disappeared from the procedure"....

If it were me, on an EPDM membrane, I'd still seal the edges of the Eternabond wtih DICOR sealant, even though the instruction step was eliminated with the popularity of TPO membrane as the "roof of choice"....