3 Black Lines On Roof

[tbone!]

I started cleaning the dicor today in preparation to seal all areas when I noticed 3 black lines which appear to be where the roof plywood meets. Any ideas what this is from and is it a concern? Should I place a strip of eterabond over the entire roof from one side to the other at the 3 locations? Trailer is a 2015 Jayco 195RB.

Thanks for the assistance.
tbone!

[JayLo]

I think you might have answered it! Eternabond, that looks like trouble brewing.

[JB13502]

Originally Posted by tbone!

I started cleaning the dicor today in preparation to seal all areas when I noticed 3 black lines which appear to be where the roof plywood meets. Any ideas what this is from and is it a concern? Should I place a strip of eterabond over the entire roof from one side to the other at the 3 locations? Trailer is a 2015 Jayco 195RB.

Thanks for the assistance.
tbone!

You're right in your thinking that it's the plywood seams. I doubt that Eternabond is going to accomplish much unless the edges of the plywood start rubbing through the membrane. Jayco typically applies mesh and/or duct tape over the seams to prevent this from occuring.
If it were me, I'd just keep my eye on it.