Rain Water Intrusion?

[travelboy]

Our RV: 2016 Winnebago Minnie Winnie 27Q. Upon removing the bunk mattress, moisture was present on the deck. The underside of the mattress was damp. I lifted the edge of the curved "nose panel" and saw/felt moisture there. If you have ever removed the mattress in your RV, you may have noticed a metal strip running side-to-side. In my motorhome, the strip is attached to the deck by 45 screws: 15 rows, 3 screws in each column. I discovered that EVERY SCREW IN THE MIDDLE of each column was broken off at the head. Yes, every middle screw! I lifted them off with my fingers. Upon removing the strip, I detected moisture, rust, and wet wood. Needless to say, I am extremely unhappy about the workmanship and concerned about the structural damage . I'll be taking the RV in for inspection and repair. Has anyone else encountered this water intrusion? If so, where was the entry point?

[Ray,IN]

This is the overhead bunk, right? Do you have a window in the front of the overhead, if you do, that is the most likely culprit. I suggest removing the window and reinstalling it with new caulking.
I had a cousin with a class C which had this leak. He spent a lot of money attempting to eliminate the leak. Finally he had the entire overhead rebuilt due to rot, about $4,000. He had them eliminate that window and never had a leak since.

Another possible source is front clearance lights. I had one leaking on our 5er. the only way I discovered the source was, when washing the 5er I noticed a water line on the inside of the lens. I removed the entire light, and found that water was getting into the lens, filling to the wiring hole in the base-plate, then following the wiring into the wall.
I sealed around the wires with caulking, then drilled a 1/8" hole in bottom of every clearance light lens on the 5er. Never had another leak.
EDIT: there's a chance the leak happens while driving in rain; there's some air compression between cab and overhead. If there is a poorly sealed seam it could force water into the opening.