Roof coating

[astegall1978]

I have a question, I have a 16x80 metal on metal. I painted the roof last october with Koolseal. I had to replace the covers on the vent pipes, so i got the plastic ones from Lowes and screwed them in and sealed it up real good with silicon coalk then painted with the koolseal patching plaster then painted with the koolseal. Now is the question...The patching plaster around and on the plastic vent covers is peeling off, What do i do now?

[Greg]

Not sure what to say here. Not much will stick to the plastic vent covers and even less will stick to silicone.

You may end up pulling the silicone off and starting over. I'm sure JD will have some ideas for you.

Greg

[JD]

Yeah, it's the silicone. Elastomeric and just about anything else won't stick to silicone. Your best bet is to remove the vents and cut, scrape and clean the silicone off of everything. It must be completely removed. I would even sand the surfaces after all traces of silicone are gone.

Instead of cleaning the plastic vents, check your home stores or better yet, go to an RV supply store and get galvanized metal plumbing vent caps. They are those simple bell looking caps. Be sure to wash the top and bottom of the screw flange with lacquer thinner or denatured alcohol to remove the manufacturing oil coating.

To seal everything back up, I would use Tremco Vulkem 116. A search for the manufacturer's web site will get you to a dealer locator link. It can be hard to find for some folks. From your local home stores, you could use DAP Premium Polyurethane Roof & Flashing Sealant. The main thing you are looking for is a roofing caulk that it will stick to elastomeric coatings without eating it up and not silicone.

Other sealants that will do the job:
Geocel Advanced Rv Epdm Roof Sealant White by Geocel
DURALINK SEALANT

[astegall1978]

Thank you so much for the info.



Allen S