I realize that you have an older roof so this is really for those of us with newer homes. I was told by a roofer that putting a coating such as Roof Max will void the warranty on your roof. So if you plan on doing an 8 year roof, you have instead, hurt yourself instead of benefitting from the expense. Incidentally, he also told me that solar panels also void your warranty on the section of the roof with the panels.

Roof Rejuvenation
 

As Credibility: I was involved with GAF - the world's largest roofing company. There are many roof rejuvenation companies on the market. I know the owners of the two largest ones. The best technology is GoNano our of Canada. The biggest one in the US is RoofMax - but - the formula isn't quite as good.

Here's why:
a) Asphalt... it literally restores the asphalt to the almost new state. Therefore, it should extend the life of the roof for 10 - 15 years.

b) Impact Resistance... THAT is what it does - better! It takes a Class 2 Shingle up to at least a Class 3 - maybe 4. That means it is hail resistant. If you are one of The Villagers who prefers not to replace their roof due to hail damage - this is a GOOD reason to have their roof done with this product.

c) Mold / Algae... prevents growth.

As it relates to insurance -the situation is not clear. There are some companies accepting it - but - to most - it is not well known technology. So - you have to ask.

Hope that helps!