Delamination in roof wood and strange black lines

[watsonjones]

Has anyone seen either of the following roof issues?

1. We have a patch on our roof where it appears as though the wood under the roof membrane is delaminating (if that is the right term). The membrane is raised in this area, just to the rear of the main air vent in our kitchen area, and when I press on it, it can support my weight, but feels like the chipboard underneath is delaminating and bits of it are raised up. No damage to the membrane at present, but it is a little concerning.

2. Less of an issue, we have always seen these black lines that run across the roof at the point where the wood roofing panels meet. Just curious if anyone else has these.

We have a 2017 3721RL (rear living - mid kitchen). We are in our RV 9-10 months out of the year chasing 70 and the rest of the time (Oct-Dec) it is stored at an uncovered lot in Georgia without a cover on it.

Looking forward to your wise words.
Thanks,
David

[jimcol]

My guess is the patch was placed there due to an incident that perforated the membrane. The plywood probably had some moisture get to it before repairs were made. Visually check the patch to insure it is sealed tight to the existing membrane. If the area is still capable of supporting your weight damage was probably minimal. I'd check it a couple of times a year to insure it isn't getting worse and continue enjoying the 5'er.
Question two, my experience is the joint lines are common and of no worry. I have them on my 06. Washing the roof a couple of times a year keeps the black down.

[RMcNeal]

The picture you posted is concerning. As jimcol said, if it still can support your weight, damage is probably minimal.
There is a roof cleaner I bought at CW for the black lines. Just spray on with a pump up sprayer, then agitate with a soft bristle brush. The black comes right off.
If memory serves, the gallon jug is labelled "Rubber Roof Cleaner" or something like that. Unfortunately, my rig is in the shop for repairs, so I can't go look right now.

[Daryles]

These instructions for roof membrane maintenance was passed out at the 2019 rally.

[phillyg]

I agree with jimcol. I wouldn't mess with the patched area unless you can tell it's getting worse, and the black lines are just from mildew drying out differently on the raised area.

[watsonjones]

My apologies perhaps I did not choose my words carefully. When I referred to 'a patch' I meant 'an area' of the roof. We are the original owners of the RV and there has never been any damage or physical patching of the roof and I could not see any damage to the membrane (yet). This is the first time this year that I have been up on the roof, but I certainly did not spot this last year.

[triplebvalp]

Originally Posted by watsonjones

My apologies perhaps I did not choose my words carefully. When I referred to 'a patch' I meant 'an area' of the roof. We are the original owners of the RV and there has never been any damage or physical patching of the roof and I could not see any damage to the membrane (yet). This is the first time this year that I have been up on the roof, but I certainly did not spot this last year.

watsonjones, the roof sub-structure is OSB. When OSB gets damp/wet, it will swell and may deteriorate the glue components that comprise the laminate.

I would suggest that you have a leak, perhaps very minor, but a leak in the TPO membrane ... or an extreme case of condensation in that area. There's really only 2 ways to determine the extent of damage to the OSB.

1. Drill a whole into the affected area and inspect the sawdust for moisture.
2. Peel the TPO back for inspection.

[VagabondLove]

Originally Posted by Daryles

These instructions for roof membrane maintenance was passed out at the 2019 rally.

What about bleach? Thanks to being parked under trees I have mold/mildew spots on my roof that clean up nicely with a medium bleach solution. I usually bleach my fresh water lines and tank, then use the bleachy water to finish up cleaning the roof...

[beeje]

There is no real need to clean the roof. It requires virtually no maintenance other than checking the seams to make sure they're tightly sealed. If you want to bulletproof it put it turn a bond on all joints on the roof and around any penetration. If you want to get it clean you can use some bleach along with Dawn or something like that just be aware that if it washes down the sides of the camper it will remove any wax that is on there.