Thanks again for your eloquent reply. I would not be a wise man to not heed your experience and advice. That said...
While I have been accused of over-engineering before...
a search on Google for RV roof leaks yields 445,000 hits. Speaking of Prevost... a search on them yields 36,000 hits. Obviously, whatever we (collectively) are doing now is under-engineered...
And the ramifications of roof leaks, unchecked, can have significant financial repercussions. AFAIC, if over-engineering is what it takes to ensure my vent to roof seam remains sealed for 10 years... ok then. This is a one-time effort, and then I am done with this problem...
It is doable: the forward hatches on my boat remained watertight long after the powdercoat started flaking off the aluminum; in spite of more than a few attempts at playing submarine
, and living in the tropics with 200" rain annually. The key there was to protect the seam seal: exactly what this flashing would do. Protect the sealant, and there is no reason the seal should not outlive the fan motor.
In the marine world, electrical wiring is typically very problematic. Living in a sea-salt environment is extremely hard on equipment. I solved that early on by crimping, soldering, and heat shrinking (with the Anchor Marine glue type heat shrink, not that crap you get at ACE) literally every single terminal and wire joint, and I re-wired the entire boat over about 3 years - thousands of joints. In the subsequent maybe 10 years I never had a single failure - not ONE. Yes, every joint took more time; but time saving was not the objective - a failure proof electrical system was.
I believe that long term solutions can be found to most mechanical problems we have. And smearing goop on a joint, no matter how good the goop (I am going to pick up some of that Sikaflex, btw
), still seems like a less that well-executed solution.
OK, all that said: I forwarded the Endurabond tape failure item over to the Endurabond guys, along with a query on application to the AS textured roof surface. Here is the response from a Mr. Rayfield Johnson, Field Tech Service Manager:
Substrate preparation is key when utilizing our EB product line. Over the years I’ve seen and heard a variety of posts both positive & negative on multiple platforms. My unbiased opinion remains the same, everyone has an option to choose the product(s) used on their personal property, with a vast offering.
Regarding your fan installation, even with the textured surface, you could utilize the ROOFSEAL (Plus) product to seal over the screw heads. On the topside of the flange just behind the screw heads, there’s room to get a good bite into the surface and that’s key to locking the EB tape in place. You could also utilize our EB primer before installing the tape as a adhesion promoter to fill in the textured surface.
Key Tips For EB:
o Clean surface with IPA (alcohol) regular household alcohol is fine.
o Prime surface with ETERNAPRIME – Let stand for 10 minutes.
o Install EB tape, slowing working the tape into place (without stretching) if you stretch the tape during installation, this will cause the edges to lift later.
o Roll the tape into place with a rubber or steel smooth roller. This will “wet out” the tape for a smooth finish but also will activate the tape to the surface. Our tape products are pressure sensitive and when this step is skipped, issues can arise later.