How to seal roof vents properly

[mountain]

Hello everyone,
I tried to find the answer here, but ....not being very good with the pc.....I gave up
But I need help. The seal/caulking/whatever around our roof vent is cracking and it looks like it needs to be redone.
Do I have to remove all the old stuff?
What do I use to seal the roof vent???

Thanks for helping
Petra

[koehlerk]

I had the same question. I found this thread helpful. I'm going to use Stainless Steel fasteners as member Con suggests.

http://www.fiberglassrv.com/forums/f...ing-24715.html

[mountain]

Thanks, that thread was very helpful.
I am still wondering though, if I have to remove all the old caulking down to the fiberglas or......????

[Greg H]

Yes.

[Reid Larsen]

When I replaced our roof vent I cleaned all the old sealant and wiped the fiberglass w/ acetone to get a clean surface, then put a layer of butyl tape on the vent and screwed it in place w/ ss screws and washers and nuts inside, pulling the vent tight to the fiberglass body. Then I cleaned the squish out of putty and sealed over the top of the joint and over all the fasteners with Dicor lap sealant. No leaks and we have had a wet Oregon spring that certainly tested the seal.
Good luck!

[Mark V.]

The old caulk should come off easily with a putty knife (or spatula) and a rag with Varsol or something similar. Rub it down to the bare gelcoat and you'll get a proper seal when new caulk is applied.