Johnny, we live in Oregon. It rains here. A lot. Steady, for days at a
time. If we leave our coaches out in it, they leak.
If the coaches never moved, sealing them would not be much of a
chore. But, they move, and flex. So your sealant must move and flex
likewise. Some sealants do that better than others. Some name brands I have
successfully used are:
Sika-Flex non hardening sealant.
3M 5200 marine sealant, rapid setting.
There are several others out there, but, I ALWAYS, ALWAYS, stay away
from silicone based products. Reasons, you cannot ever successfully paint
over silicone. And it is a bitch to remove.
One other product that I have used is a tape like product that comes
in rolls. It has a peel off membrane that you remove as it is applied. It
is the stickiest stuff that I have ever had my hands on. I use it where the
roof end caps join the aluminum roofing. It costs, my price, over $10.00 a
foot. That's why I don't often recommend it to the GMC community, they are
a cheap bunch, no matter what the quality of the product is. But the stuff
works, period.
Today, I just came from the E.R. and had my nose cauterized. So, I
can't remember stuff like the manufacturer of the tape. If you like, I will
stumble down to the shop tomorrow and find the roll it came on.
Jim Hupy
Salem, Or