white, reflective coating for heat control

my grow room is the rear part of a garage, that has a black, torch down roof. i got to thinking about heat. so i purchased a 4.75 gal bucket of this stuff, that claims 83% light/heat relection. i have yet to do the rest of the roof. just overlaping my grow rooms. it will be interesting, to see if it helps. anyone else done this, and the results were?

nop, but Im sure it would be a good idea to finish the hole roof, both since the rest of the garages might warm up the grow area and so it look nice and tight, I would wonder why "this guy" only painted half his roof

and I also know that my work place just got some sun film up at there windows that reflex the light away as they had very hot temperatures in the office, dropped maybe 10F in there afterwords, not like a green house anymore when sun shine on the building/windows