[JRTJH]

This is just one theory, but bear with me and see if maybe some of the puzzle pieces seem to fit....

You have a trailer with wood walls, very little insulation and 0.022 aluminum siding. The interior wall is 1/8" luan paneling which is not well sealed to the wood structure, but stapled in place and "somewhat sealed" where the window moldings hold it in place and where the edge/end cap moldings cover the gaps.

You have a recent history of excess humidity in the trailer (bathroom vent condensation) and concern for moisture there as well.

Now, to the theory: There is some moisture migration from the "wet interior air" into the gaps between the luan and the wooden structure. That moisture condenses on the cold aluminum since there is no "real dead air space" created by the "minimal insulation in the walls" and worsened by not having any moisture barrier in any of the walls.

So, the "moist air" condenses on the aluminum, runs down the wall to the floor and seeps out, making the carpet wet.

Now, in the past couple of days, you tear out the luan and what little insulation is in the wall, essentially opening it to constant contact with the moist interior air. As the outside temperature falls, the unprotected aluminum sheeting gets cold and when the temperature falls below the dew point, all that interior moisture collects on the cold aluminum surface and it "literally rains every night inside your trailer"..... What you see "tonight" is not the typical condensation that would occur, so it probably appears much wetter than it would be be if the luan and insulation were in place.

What I'm suggesting is that maybe the amount of water collecting on the unprotected metal sheeting is not what normally happens, but is collecting like that because you removed all the barriers that were in place and you made the situation worse than it was...

Now, some possible sources for the water stains that are visible. First, I'd remove the windows in the slide and reseal all of them. The clay putty tape used at the factory, especially on the "corrugated aluminum skin" just doesn't seal well and a tiny "pinhole leak" in the window will cause the extensive water stains that you have. Also, plugged weep holes in the window moldings will cause the condensation that collects on the windows and "seeps out of the window to the exterior" can leak into the inner wall and cause the staining you have.

I'd first seal the windows, reinsulate with a spun fiberglass insulation with a moisture barrier on the surface next to the outside wall.... DO NOT INSTALL THE MOISTURE BARRIER NEXT TO THE LUAN PANEL... If you can't find 2" fiberglass insulation with a moisture barrier, you can make one by using a plastic sheeting paint dropcloth and stapling it to the walls of the slide, then use spray adhesive to hold the fiberglass insulation in place and reinstall the luan paneling.

If you get the idea that I don't think you've got an active leak, you're right. If you do have an active leak, I would first suspect it's from one of the windows that was inadequately sealed and/or that is leaking into the wall. I honestly think that all (or at least the major part) of your water problem is condensation caused by inadequate ventilation/air exchange inside a poorly insulated trailer and two people living in a confined space without enough ventilation.

Frankly, I think you're trying to live full time, during a wet winter season, in an entry level trailer without making the accommodations in ventilation/dehumidification that are mandatory in such a poorly prepared and inadequately constructed trailer.

That's not intended to be any negative reflection on your situation, your need for housing or for your intentions. Rather it's a reflection on the capabilities of the trailer, using it as a full time residence for two people and expecting it to be as comfortable and to perform like a "full size house". Most homes are 1000+ square feet with 4-8" of insulation, built in ventilation in the attic and enough cubic feet of "inside space" to readily absorb the moisture that two people produce. You're trying to make a 225 sq ft box with no attic, no air movement above the ceiling perform the same way as a full size house. It simply can't perform that way. Add "metal walls with no vapor barrier, 1" fiberglass insulation, single pane windows, two people breathing, cooking, showering with limited ventilation and you can start to appreciate how hard it is to keep the inside of that "little house" dry and comfortable.

It's simply not designed to do what you're forcing it to do. Without "work-around" moisture removal (dehumidifiers and power ventilation) you probably won't be able to prevent the walls from being wet, but adding a vapor barrier and adequate insulation would be a start.

I'm guessing that if you remove the slide window directly over the leak in your photos, if you look closely at the clay putty tape, you'll find a "water track" and/or dirty spots where the putty tape didn't seal to the trailer skin under the window flange. My guess is that is where the majority of your water stains originated and now that the metal is exposed in the evenings, all the moisture in the trailer is condensing there. Get the wall reinsulated and closed with new putty on the window and you'll probably find the carpet won't get wet any more.