I've been fighting leaks
this spring (wet! winter) and maybe I've found a major culprit. I had been investigating, based on reading various threads, the possibility of leaky belly-band rivets.
After I had the interior cleaned and de-mungified this spring and was feeling pretty good about things then I opened the trailer up one fine day a few months back and was faced with a ugly-coloured mess in one corner where water had obviously evaporated leaving behind a rusty looking scum. (1st. image) This "rust" coloured mess made me think about the belly band issue. (I know, the rivets are aluminum, but I was somewhat ![at]#$ off at finding a new leak).
So, based on where the source seemed to be, I carefully peeled back the ensolite on the wall to see what the inside ends of the rivets looked like. Just like they are supposed to be, the ones I could access were still nicely encased in their fibreglass pockets - no sign of leakage (hose test, with verve). But, I felt a wetness partway down the wall.
Close inspection showed what appeared to be a small plug of silicon sealer. Hmmm... A poke with a sharply pointed scratch awl confirmed - a plug of silicon filling a small hole. When I inspected from outside it appeared the plug was filling a (deep) rock ding. The front of the trailer has a thickish coat of paint
which I assumed was a "rock guard" type coating.
(Picture 2 shows some "dings" from the inside, with "plugs" removed and picture 4 shows a few from the outside)
Further inspection showed a number of odd looking blemishes (picture 3) around the front of the trailer. Probing with the awl showed most of them were little plugs of silicon covered with whatever paint
some previous owner had decided was suitable. (Whomever had this before must have done a lot of gravel road driving - with some speed to cause this many holes in the FG.)
Now that I've poked a bunch of holes in my trailer I have to fill them. I plan is to use one of those marine epoxy putties forced in from outside (as I don't want to peel any more ensolite back - it's still stuck "real good" after all these years) after I clean out what silicon I can and prep the area.