Roof issue

[whiterose]

Had a 2016 3790RD, we camp east of the Mississippi, so always plenty of trees around. General condition of the roof was good, but dark lines were present corresponding with the position of the struts, that support the plywood and covering. Tried to clean; even used the roof cleaner neat, slight improvement, but still there.

Any idea what the cause is specific to the lines, and an effective method of removal.

Reason in asking is that we are taking delivery of a 2018 3791RD and don't want to repeat.

[Linnea]

Not sure if this info will help but we had a similar issue with our 2014 Montana FB3900. The service center discovered that several of the underlying "staples" used to secure the roofing material were starting to pop up leaving spots on the roof. They had to peel back the roof material, remove all staples and replace by screwing down what lies under. They said it was clearly a manufacturing error. Over time, those staples would have punctured through leaving the coach vulnerable to water leakage and eventual mold.