Do I Really Have To???

[Swrider]

Sooo, i am in the slow, tedious process of sealing the roof, and I'm wondering if i really need to scrape up all the old sealant?
In the case where im replacing the vents, yes, im cleaning it all up so i can start fresh.
But what about the places where 95% is ok and i really only need to retouch some cracks???
Can i get away with just adding more sealant there, or maybe just tape over it???
Thanks.

[cwf]

Cleaning is important... then seal.. then BUSKOTE

[lsbrodsky]

You cannot just touch up caulk and expect it to be leakproof. However, 3M 4412 roof tape can be applied over a properly prepared caulk line, if you buy it wide enough and follow the directions.
Larry