Have Unusual Roof Leak


Hi All,

Having a very difficult roof leak to address. On the rear left side of the roof, I have noticed water coming down on the fiberglass when it has not rained for a long time. The water is running down the fiberglass but the roof above the gutter is 100% dry. All I can think is this is A/C condensate (the A/C was definitely running). I removed the A/C cover and checked the drain and it was not obstructed in any way.

Another thing I found was about 1/2" of water in the rear center furnace duct on the floor about 2' in front of the rear window. (there's no water in the pic). Don't know if it's related or not.

The water has caused the particle board flooring on the left/rear part of the camper to deteriorate and become soft and fall in. When I stuck my hand down below the floor it was all wet. In addition, it looks like the lower fiberglass behind the left read slideout and the left rear is end bowed out from swelling.

Could it be condensation from the ducts in the roof? Any ideas welcome!!!




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Staff member
It sure sounds like you have a leak somewhere in the rear.
Have you ever inspected and/or done any caulking at the rear window and area where the rear cap meets the roof?
Water leaks can be very difficult to track down.



Well-known member
I notice in one picture you have cracked fiberglass in your outside wall by slide. Not that this would be cause but it does mean things have shifted. I found a leak entry point behind a D seal metal holding piece.

I’d recommend simply removing all your caulk and D seals and inspect everything. My guess you will see where the water is going in, repair that then reseal everything and then water test to be sure.

It is probably water from the a/c unit trickling in over time.


Well-known member
If it hasn't been raining in a while. the air conditioning unit would be my main water source suspect. It might be worthwhile to remove the top unit, inspect and install a new mounting gasget, along with making sure that the condensate water goes along the channels it is supposed to within the air conditioner, and has plenty of drain holes onto the roof for the condensate. I drilled additional drain holes into the air conditioner pan at each of the 4 corners of the AC pan.

If the roof is still somehow suspect, I would strongly recommend you consider some total roof sealing overcoat such as Henrys TropiCool 887 elastometric roof sealant. It is in stock at most Home Depot stores, along with its special repair caulk. Here is a link to the Amazon listing which has a lot of reviews: