Rvalue of Garage Door Insulation What is Rvalue?Basically, the higher the RValue, the more the insulation is going to resist the movement of heat in or out of your garage Naturally, insulation with a higher RValue also has a higher initial cost The idea, is if you install a higher RValue insulation to begin with, then you'll see long term savings in heating (and/or) cooling costsIf the joists are 10 inches deep, the cavity can take highdensity R30 insulation, which is 8 1/2 inches thick, more than enough for floor insulationIf the garage is open to the rafters, the boards that support the roof, use R38 insulation between the rafters at the roof, if they are 10 inches deep The Best Garage Door Insulation Kits Garage Door Nation What r rating insulation for garage ceiling