smkettner wrote:
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No one is saying to just slap a coat of Dicor on a mess like that.
I would not even offer an opinion on that repair except to say it needs to be torn apart.
There's something to be learned from your observation. First of all, this mess was started by someone slapping a coat of self-leveling caulk by mistake (initially). Obviously, a goop that gets hard and cracks and starts lifting, in 2-1/2 years of being exposed to normal elements which other RV roofs endure, is NOT the proper way of sealing this type of joint. You certainly wouldn't want to redo this type of "gooping" every two years. Certainly, not on a "$175 thousand plus motorhome". The proof of this is knowing that Newmar realized this, and for the next year-model incorporated a standard all-fiberglass roof, made in a mold and without lap joints. So, buyer beware.
And, the first step in fixing this mess is to remove all of the goop that failed, and all the wrong screws (over 800). I won't bore you with the rest of the steps.
Of course, if you're working by yourself OUTDOORS, you have to temporarily seal the area that you've completely exposed, every time rain is in the forecast (even if only a 10% chance). Bottom line, it takes a very long time. However, I did find a special tape called ShurTape which works for temporay sealing. It sticks good, with good conformity, rain won't break it down, and it comes off when you're ready to come back to do some more permanent-type work.