During some initial cleanup on my newly purchased (used) trailer, I noted the ceiling light fixture had some rust at the base of the threads that retain the bowl. Likewise, the glass bowl itself showed evidence of a small amout of water being in it at one time. The nearest roof fixture to this area was the TV antenna, so today, I went up to do some exploring.
The area initially appeared to have an adequate seal around the antenna, but as I poked around, I noted a two inch crack filled with mildew. Uh oh. I also noted the rubber roof seemed to be bubbles, not really visibly, but I could push down with my palm and feel it give before reaching a solid surface underneath. when I walked over the area, it seemed solid, but there was an audible crunching.
Out came the putty knife. Dicor is a real b*tch to scrape off of rubber. Opposite the crack on the foot of the antenna pedestal I exposed a screw head. It wiggled as if unattached to any surface underneath. However, the whole unit seems quite solid and is unlikely to come off at this point. I opened the crack as you can see in the photo and observed dry rot on the luan. I found it very difficult to remove the putty without damaging the rubber roof. I used my fingers to manipulate the rubber and found the edge of the luan several inches away running perpendicular to the trailer. The area that I can tell is damaged underneath the rubber is roughly framed by the broom handle and on the other side by the putty knife (where the distinct edge of the luan can be felt). As far as I can tell by feel, the area near the a/c unit is solid, but downgrade from the antenna it extends a foot or more. The interior of the trailer shows no water damage.
My question is: Where shall I go from here? I'm a complete amatuer, shall I remove what putty I can , clean up the rest with mineral spirits and reseal? Mind you, the roof still appears solid, but I know it can extend farther, much farther than I have observed. Is there a trick to scraping up this stuff?
What would you do? Bring it to a professional? Remove the rubber, cut out the damage, rebuild and put a patch on the roof? I'm at a loss right now.