Aluminum Roof Pitting & Disentagrating

[Roaming_Eagle]

Recently purchased a 1 owner 2008 Eagle. After 2 months of ownership I found out in the middle of the night how leaky the roof is. After reading forum after forum on the probable cause I got out ladder and started replacing the screws and rubber washers only to notice that around 60% of the screws were smaller holes where the aluminum had been eaten away. Anybody else have this same problem?

I'm probably going to just JB weld the holes but open to other ideas?

 

[Andy Douglass]

I wonder if it was parked near the ocean long term and had salt water sitting on it? If the fasteners are steel and there is no barrier between the aluminum skin and the steel, maybe the corrosion could just be caused in the presence of non salt water? Boats with aluminum hulls, propellers, or other parts use sacrificial zinc anodes to stop this kind of corrosion. I am new to the "RV" world, but I haven't heard of anodes being used on land vehicles.

 

[shellback]

Just a WAG, But electrolysis could be causing the problem. Using the roof structure as a ground for fans, lights, or solar power could be the culprit. Electric current and the dissimilar metals, aluminum skin and steel screws, will cause the problem. You may be able to use a meter and see if you get a reading between positive battery and the metal roof. I know with aluminum boats you should never use the hull as a path for ground. I had some roof screw holes elongated, and epoxied thin 1/2 x 1 inch aluminum plates over the holes, then rescrewed it.

 

[PokyBro]

If you look around you can find washers with neoprene fused to one side , and use 3/4" #8 hex screws to fasten them overtop the neoprene washer. I used #10 metal building hex screws with rubber washer (found at Home Depot) for my elongated screw holes, one size larger screw, then I sealed overtop the hole screw head for a one inch circumference with an RV sealant called Proflex, made by Geocel. Seams good so far. Just one other idea for you.

 

[ckent323]

If the problem is due to electrolysis then it seems to me that even the thread contact by a steel screw will be problematic and the rubber washers will not eliminate the problem.

Since the roof is Aluminum and the frame to which it is attached is Aluminum then replacing steel screws with Aluminum sheet metal screws would likely solve the problem since there would be no dissimilar metal to cause electrolysis.

I am wondering if this problem is actually due to electrolysis and if so why are more owners not experiencing and reporting this problem?

Is the problem only limited to the screws in the roof and not present in screws the rest of the camper?

 

[Squatch]

FWC does use the roof frame for a ground. There is a ground plate inside the little roof box where the solar stuff goes through. The plate in my camper had some loose screws in it. That could be part of the problem. Ground but not solid ground can be an issue. As can salt. be it from road salt that wasn't washed off or as said above about ocean locales.

Also the roof flexes a lot on these campers. That can and will elongate holes in the covering skin.

 

[Roaming_Eagle]

All right after much pondering and consideration, I believe it's due to the fact that the original owner stored the camper for a year in Ocean Beach CA. So far it's only limited to the screw holes I'll try to upload a picture later.

I have gone ahead and replaced with new rubber/aluminum washers and stainless steel screws.