While making a few repairs to the roof of this 88 beast I found that a crack had been previously repaired but the patch was applied directly on the gel coat surface with no prep. Needless to say the fiberglass patch pulled right up. In the process of removing old antennas and such I discover that when this unit was repainted, they did not prep or even wash the top before applying paint. so in the sanding prep of the repairs I found the paint coating tearing off in piece and revealing the dirty top. I wet my finger and the dirt cleaned off so it wasn't stained. Took two weeks to prep the top for a EDPM coating. Bought a 5 gal container of the EDPM and worried if that would be enough for a 40ft unit. Turned out to be too much. It applies thickly and it will run on where gravity has an effect. My biggest regret is not taking a pint from the unmixed can and appropriate amount of hardener for touch up. I did my unit yesterday in the bright sun and thought I looked it over carefully. Today as I pulled off the tape and paper off the sides I found several small missed areas. I took the coating down to the drip rails on the sides, down to the windshield in front and down to where the rear is indented, all the marker lights were removed and the AC unit (original unit) was removed as I am replacing it with a new unit. Needless to say, I slept good last night.
What product did you use?
Used ProGuard roof coating for RVs, got it from Amazon with DiCo caulk. Living in the south I have a variety of bugs and pollen (I live next to a renewable pine forest) sitting on top. I suspect most will wash away. Did order another gallon so I could do some touch up. Had to install the rear air unit as they are calling for rain tomorrow and the toe of my shoe got off the cardboard and left me an area to touch up. Needs several day of warm weather to completely cure.