Installing Slate On Drywall Need To Know What Size Thickness Of Drywall To Use In Garage?

Need to know what size thickness of drywall to use in garage? - installing slate on drywall

I live in Wisconsin and the installation of gypsum board will be in my garage. I have three walls that are full and my "party" a wall of slate. While only three walls of the wall studs. I use 1 / 2 inch thick, but in Wisconsin, was 5 / 8 "? I am sure that I do for the code.