Mystery Bump

[slaglefam5]

 We just popped our trailer open for the first time since March in preparation for camping next week and discovered a weird lump in the ceiling, almost tube shaped, near the exhaust fan that extends to the edge of the ceiling. It's hard to the touch so it doesn't feel like water damage and there's no moisture inside the trailer. What could this be?

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[way2roll]

Can't access the photo but, usually a mysterious bulge is a result of water intrusion. 

[IB853347201]

Definitely sounds like water intrusion to me. I would definitely get up on the roof and inspect the sealant along the seams around the vents and such.  

[StirCrazy]

might have more luck posting in the trailer forum, this one is for feed back on the board its self so might not be viewed much.