Newly coated roof staining from oak tree
 

I coated the roof with Dicor Coolcoat and it really looks good and I hope helps with stopping some of the suns heat from penetrating. The best place that I have to park the motorhome has old oak trees around. The shade is nice but anything that falls from them is leaving a brown stain. The coating dried very white and has a flat finish (not glossy). Any ideas of a sealant or coating that will seal and protect it?

This affects the appearance only. If you choose to park under trees, your only option is to cover the roof or construct a MH-port roof, because whatever you put atop the new coating will also stain.