Algae on roof not on painted ends, and prevention

[Florainer]

When cleaning the algae (and lichens?) off my roof recently I noticed that there was none on the painted ends, front and rear, or on the narrow painted strip along the sides, It was only on the white area that makes up almost all of the roof. My 2003 HR Imperial has a full-length one-piece fiberglass roof. Why is there no algae/lichens on the painted areas? Also, now that I have it cleaned off (a lot of hard work!), is there anything I can do to discourage its regrowth? The rig is stored here in Florida in the winter, an admittedly ideal condition for algae growth (hot & humid). I've read that copper discourages algae growth, but is that ever used on an RV roof? Thanks for your replies!

[Paul J A]

https://dicorproducts.com/ has everything you need to maintain and protect the roof.

[JohnC3]

My suspicion is that the algae is digesting the breaking down gel coat of your white top.

You can use the Dicor stuff, but that may not last as long as you like.

From anecdotal evidence, I believe that painting the white portion of the roof with Rustolium (sp?) Marine top coat will help for 5-7 years. It will also prevent the streaks down the sides of your rig (what I did it to prevent).  It takes 2 coats at about a quart a coat. Look it up over in IRV2 forums. They have looked into a number of products.

The paint costs about 18/qt and can be applied with a roller and brush. It takes about 3 days as it needs to dry well between coats.

Hope this helps.

[Florainer]

Considering all the posts on this site, and on IRV2, about dealing with roof chalk, including Mop & Glo-ing, waxing, painting, etc., why did Monaco/HR not paint the fiberglass roofs of their motorhomes? One reason I can think of is slipperiness, which could add to the danger of going on the roof, but are there other reasons? 🤔 And if the treatments talked about on these sites do increase the slip danger of the roof is that something to consider before going ahead? 🤔