Visit your favorite camping supply store and purchase roof cleanser, sealant and a brush to apply it.
Remove your shoes and climb on top of your motorhome. Taking your shoes off prevents debris on the ground from making its way onto the roof.
Clean the roof with a good non-petroleum roof cleanser and let it dry. Do not apply a sealant before it is dry because it will not be as effective.
Brush the sealant as a thin coat as if you were painting a wall. A paint roller can also be used. Follow the manufacturer's instruction on the side of the sealant can.
Allow the sealant to dry overnight in a dry location.
Check the roof to ensure that you sealed the entire area. Look for any patches that are not glossy looking.
