Stringers would equate more to the main framing of the trailer, which is aluminum. This issue would more represent hatches or windows leaking in the cabin and causing delamination.......
Sounds like this happens to trailers only a couple years old. I suppose they leak from factory, just takes a while to notice the damage... Need better quality control.... Or, maybe any kind of quality control.....
Actually every single trailer and motorhome that is built goes through a leak test tunnel, problem is, there is no way to test them after they have bounced and been run up and down the road, they shift and move so much when they are being towed with the road, it is amazing what they go through on the road. I suspect what happened in they did put the sealer in the window, but failed to tighten it down as much as it needed.
What you need to do in the spring is pull the window and you will probably have to fix a couple of studs in the wall right under the window area, which is really not as hard as it seems, then get some putty tape, put the window back in and tighten it back down until the tape just starts to squeeze out, then trim with utility knife so the putty tape is even with the window frame.
Then it will need to have a sealant applied along the top of the window frame and I am not talking about RTV, RTV is not for RV's the stuff does not hold up, they make special clear sealants for use on RV's
You want something like this:
http://www.ebay.com/itm/Geocel-ProF...ash=item1e8fa0b3fe:g:p3oAAOSw34FVDfLp&vxp=mtr
It will last several years. Also if you have delamination going on in the outside wall, when you pull the window, you will want to pull slightly on the outside wall to see if it has separated from the luan if it has put small shims between the luan and the outside filon and let it dry for a few days, then get some 3M industrial grade spray on contact adhesive and spray is much as you can down inside between the outside and the luan and then between the luan and the studs, let dry for about 20 minutes depending on temps and then squeeze them together and let set for a couple of hours. Make sure to get the red contact adhesive that way it will not eat into the foam board insulation.
If you have any questions when spring gets here, don't hesitate to let me know, or send me a PM and I will send you my number so I can answer any questions that you might have.
