Roof Coating DIY

[Sam G.]

So my roof is not currently leaking but I do need to have some areas patched up. Roofer recommended patching up any areas that need it and an aluminum coating on the entire roof. Total of $1900. Was told I should get 5 years of life out of this. 

Property is a 2 flat with about 1k sq ft per unit, not very steep roof either. Is there an advantage of aluminum coating vs any other type of coating, since it will be coated both ways. Will the roof be silver? Not sure that would look best. 

Is this something you would DIY since it sounds similar to painting. Any thoughts on roof coatings in general or wear experience? Thanks!