Condensation between ceiling and roof on Pop-Up

[fotophreak]

Hello Everyone! I have a problem that has developed over the last couple of years. I have a 2011 Palomino Pop-Up trailer that has decided to collect water between the roof and the ceiling. The problem began after I started tarping the trailer for winter storage in the Pacific Northwest. I believed it was the roof leaking but the tarp was waterproof. Despite this, I moved the trailer into the garage and I resealed the entire top, including replacement of the corner caps. Once the caulking was cured, I moved the trailer back outdoors and covered with tarp again only to find more moisture leaking through the overhead lights and other ceiling penetrations. There is NO moisture in the cabin area, ONLY between the ceiling and the roof. The water leaks into the cabin from the corners and lights and soaks the curtains and has made puddles on the beds. I've tarped the beds for now. Yesterday, I squeezed the weather seal along the door side and water ran out the end. Has anyone else had such a localized water intrusion during idle storage outdoors? This is madness.
I did purchase a 'breathable' top but the problem persists.
I have not used a de-humidifier or passive heat source to keep the cabin warm during storage and believe this to be the next step, given I have sealed any likely leaks. Your helpful comments will be greatly appreciated.

[MohicanJeff]

If you have a roof air conditioner or vent, it is quite possible that the gasket is bad and allowing moisture to penetrate. When mine failed I was able to trace the leak by using a garden hose to confirm. Good luck and be sure to keep us updated.

[fotophreak]

Thanks Jeff, I'll take another look at that seal on the vent cover. I removed the flange inside the coach while getting it dried out yesterday and could not determine that water was entering via that avenue. I keep trying to convince myself it's just heating and cooling of the top that is causing the moisture to accumulate over time and it can't get out because of the cover. I hope I don't have to disassemble the ceiling.

[GalsofEscape]

what kind of tarp are you using? you should be using a cover designed for RVs and not a regular tarp as the RV covers are designed to breath and not allow moisture to accumulate under it.

[rsdata]

I believe you should put in a powered de-humidifier while covering the top with a tarp since you seem to have clearly eliminated water intrusion from the top, probably leaving only condensation as the only other way for moisture to accumulate

I would also add a small fan inside to move the air around blowing from the floor to the ceiling

[fotophreak]

I am using a CAMCO breathable cover.

[fotophreak]

I ordered a dehumidifier but to my chagrin, the thing only works down to 47° after-which, the efficiency drops considerably. I'll be sending that one back before ever trying as we have temps well below that for much of the winter months. I'm considering a light bulb on a timer for passive heat in the small space when collapsed. A fan, maybe. The slide out beds will baffle air circulation inside during storage.
I'm wondering now if it's a greenhouse like atmosphere in there with a cover on the top.