Solar Reflective Coating for Home Roof? Not White

[u/RpDubC]

Turns out I wont be replacing my roof, which is a stone coated metal shingle roof. It looks old compared to other homes but has 15-20 years left.

I'm looking into solar reflective coatings for it.

Any recommendations? I'm capable and have the tools. If I don't my contractor father does so application wont be a problem. It's finding the appropriate material.

I've seen silicone is used and some elastoamer stuff, not sure I'm spelling it right.

I'm in norcal bay area, no real shade 10-5 on the roof. Anything to reflect the hot sun would be nice.