What is this

[jar3316]

This is my father in laws wildwood 5er its about 10-12 years old and has alum on the out side and siding on the inside. There is no visible marks or damage on the other side of the 5er but these appeared about a year ago can any body help him figure out what has caused it and if its a real problem or not.

[Av8orLou]

Looks like delamination caused by water getting in the wall somehow.

[murry]

Look like staples under the wall papper working there way out..

[Rrickim63]

Gently press around the bumps. If its spongy,it's definitely water damage in the early stages.

[jar3316]

Its been a while since I've been in there but if memory serves its pokey in the middle and soft around the edge like a pencil pushing out.

[huntr70]

Water damage....definitely.

The bumps are probably hard, they are black mold that grows under the vinyl wallpaper when wet.

Look for a leaking screw under the trim where the rubber roof meets the siding. Usually those screws can work loose over time, and the water will travel under the trim until it finds that screw. You should be able to take out the vinyl trim strip and find screws underneath it.

[jaycee611]

Definitely water damage.
Fix the leak source and clean up the affected area with bleech or other
approved cleaner.
You may need to cut out the bad paneling and replace it.