Sealing verticle joints of aluminum siding

[Hank Hill]

I have a 2015 264bhw and have been very pleased with it. The question I have is that the black streaks that form on the aluminum siding seem a lot more prevalent at the juncture where the siding pieces join each other. I have not had any leaks but its almost like moisture is coming out of those joints though other than the black streaks I don't see any moisture. Has anyone sealed these joints with the non-leveling Dicor or some equivalent? I feel that it would be beneficial especially on the front when driving in the rain to prevent the possibility of any moisture being driven in the joint.

[Marcm157]

The siding just like on a house needs to breathe and should not be sealed. Most black streaks come from oxidation on the roof. They are a fact of life in the RV world especially those with aluminum siding...

[Sundancer330]

Black streaks come from any water or moisture that runs down the surface of anything. As the water runs down the side of a camper, trailer, boat, or anything it has pollutants in it. Some of these pollutants are left behind as the water runs. The more rain or moisture there is the faster the pollutants build up, thus a black streak is formed. The dirtier the the roof is on your camper or trailer, the faster the black streaks will form, because this will only add more dirt to the water as it runs down. Around windows on campers and trailers, the water gathers on top and then runs down in more concentration on each side of the window. Black streaks will ruin your investment if left untreated. The streaks are not from Oxidation.

[Marcm157]

Originally Posted by Sundancer330

Black streaks come from any water or moisture that runs down the surface of anything. As the water runs down the side of a camper, trailer, boat, or anything it has pollutants in it. Some of these pollutants are left behind as the water runs. The more rain or moisture there is the faster the pollutants build up, thus a black streak is formed. The dirtier the the roof is on your camper or trailer, the faster the black streaks will form, because this will only add more dirt to the water as it runs down. Around windows on campers and trailers, the water gathers on top and then runs down in more concentration on each side of the window. Black streaks will ruin your investment if left untreated. The streaks are not from Oxidation.

Copied and pasted directly from streak master website. A site trying to sell you something. Not saying it's totally inaccurate but the majority of streaks on my camper come from my roof. I can attest to that fact personally...

[Sundancer330]

And whats on your roof, airborne dirt

[jloco]

Keep the roof clean and keep a good coat of wax on the aluminum siding. This helps with black streaks.