Look at this website epdmcoatings.com, I just bought a 5 gal pail of their Liquid Roof. Good videos to view on preparation and application. I have all of my prep completed and hope to apply the coating this week depending on temperature. Could reach 90 degrees Monday.
My roof is 11 years old and needs attention. Half price shipping through 10-31-16. There is a chart to guide you in ordering the right quantity base on the unit size.
The hardest part of the job is the prep work, at 72 years old my body is letting me know that I scraped and replaced caulk and scrubbed the roof surface.