We are working on a project that has roughly 1,000 s.f. of roof area covered by stone ballast. I've looked at another LEEDuser post about this, but it was from 2013, so I'm hoping there's some new insight on the topic. It seems that ballast is considered by sources to be a "cool roof" material, and acceptable for reducing urban heat island (provided that the ballast has a high reflectance SRI >30).
Has anyone had any experience with using ballast towards this credit for the "area of high-reflectance roof" portion of the equation? It really doesn't make sense to ignore it, especially if there isn't enough data/ research out there proving that this design strategy is detrimental to the urban heat island effect.
Thanks for sharing any comments and/or insight!