Commercial roofs are essential for every business — they shield your company from the elements and add aesthetic value to your building. Elastomeric roof coatings can extend the life of your commercial roof by years with proper installation and care. Customers often ask, how long will an elastomeric roof coating last? The elastomeric coating can last up to 20 years in the right conditions. This all depends on the mils of the coating that's applied. A 10-year extension requires 20 mils of coating, while a 20-year extension requires 30 mils of coating.