Here's an update on my water damage as I dug into it-
The photo links should open up photos illustrating the damage.
My Wildcat is a 2007 model that was only used 3 times (health reasons) each about 2 weeks, and has sat in Central Texas in a pretty dry climate, looking essentially like new (except for some fading and edge curling of the decals) and until a couple of weeks ago showed NO DAMAGE in or out. At that point I noticed some small delaminated spots at the LR wall of the RV where it meets the back corner molding.
After tearing at the OUTSIDE corner, and installing a new vertical corner 1X2 I went inside (since the apparent invisible leak had been thoroughly sealed) to take a look. THe back wall on the left side was "soft" to the touch, so I started by cutting the wall paper away, finding decomposed luan behind it, which I removed, including the fiberglass batting.
Picture: 2014-10-09_2346 - bobinyelm's library
With the batting removed, I could see further damage and mold inside.
The horizontal 1X2s and even the 2X4 were completely rotted away and didn't even exist at the outside ends anymore! What was left was spongy wood one could break away with a fingertip. AMAZING none of this showed inside or out until just a week or so ago, when it "blossomed" seemingly all at once. I'd been inspecting the roof and corner caulking pretty much consistently, too, and nothing was obvious, or even slightly noticeable!
Picture: 2014-10-09_2333 - bobinyelm's library
Picture: 2014-10-09_2332 - bobinyelm's library
The little "box" holding the power cord and enclosing the fresh water fill port had considerable mold inside on the carpet. The fill tube was bent at installation so water may have dampened the carpeting though the tank was only filled maybe 3 or 4 times since new. The first time I filled the fresh water tank, it let loose from the chassis, and it was sagging through the corrugated plastic belly liner, telling me it was no longer secured in place.
I called a Forrest River dealer, and they said NEVER EVER fill a Wildcat tank and attempt drive with it. It's meant to HOLD water, but not to transport water. Just plan on filling it when arriving at the campground (Who knew?). I built an angle-iron frame UNDER the tank (bolted to the trailer frame) to support it so I could transport water, BTW. The only thing holding the water tank up from the factory is 2 lengths of metal plumber's tape barely able to support the empty tank, so the dealer was RIGHT, BTW, but I digress. I mention it to preclude having a tank drop to the ground on the highway.
Here's a photo of the area inside the power cord/water fill tube box showing the mold: 2014-10-09_2332 - bobinyelm's library
I removed the (former) structural members and cleaned everything down to the luan next to the Filon rear outside covering. The only luan is about 1/16" of the former 6mm thickness.
Picture: 2014-10-09_2331 - bobinyelm's library
Tonight I cut new lengths of 1X2 and 2X4 and glued/screwed them to the "good" wood that was left. Note the new vertical corner 1X2 I'd previously installed from OUTSIDE. It, and the wood near the window are what I secured the new wood to. Thank goodness I hadn't attempted to use my trailer's ladder-the wood under it was GONE. Now it's screwed to a solid 2X4 as originally.
It was too dark to photograph the structural members after installing them tonight.
I plan to brush the remaining luan with polyester resin and a few layers of synthetic cloth and over the new wood to make a "fiberglass" frame with some additional rigidity for the back wall, and the install 1.5" of rigid "pink foam" as insulation between the structural members secured with polyurethane construction adhesive to complete the back wall (should add R-8 plus sturdy-up the area), and then put some panel I found at Home Depot that looks very much like the OEM wall paper.
I might mention that the back wall was poorly constructed and was only 1.5" thick inside, with no vapor barrier, and only some unbacked fiberglass batting in there for token insulation. If I has sustained damage to more than just the one side, I'd have constructed a whole new back, wall, and built it properly. As it is, this should suffice, and I will next Spring re-locate the trailer in the Pacific Northwest and keep it under a large metal carport structure, because it's obvious Wildcats are not built to actually be outside except when actually on camping trips. Until then I will carefully inspect it WEEKLY while it's out-of-doors, and maybe block the gutters far from the corners of the trailer and let the water spill down away from the trailer's vulnerable corners.
Part of the "problem" as I now see it is that the corner moldings are about 1" wide on the back wall, but only wrap around the side walls about 1/4", and micro-gaps in caulk can allow moisture to get into the corner walls and migrate into the rear wall.
When my repairs are done, I plan to again remove the existing molding, and install 1X1 angle aluminum I will have formed from 0.025" or 0.031" aluminum onto the corners with liberal caulk underneath, and re-install the OEM molding to secure the new corners and provide enough overlap to prevent what appeared to happen this time.
More pictures as the work progresses.
I don't pretend that this is the RIGHT way to rebuild the corner, but rather an expedient way. Short of a lot of money, or time and less money, there is no way the trailer will ever be "like new" and given the steep depreciation curve of these units, spending a lot of money cannot be justified IMO.
As a side note, I found my Rockwell "Multi-Tool" invaluable in deconstructing the coach. It's micro-vibrating blades of various types enabled me to cut through wood, staples, and even 2X4s without shaking the structure apart (as a Sawzall would do), and enabled precise cuts down to, but not through, anything I didn't want to. A lot of manufactures make these now, copying the German made Fein Multi-Tool introduced a few years ago. These are GREAT tools, regardless who makes them!
Picture: 2014-10-10_0028 - bobinyelm's library