I just traded my Home depot bought century stove in for a Hearthstone Shelburne. I was wondering if i need to hold my cement board out an inch off the drywall for an air barrier since i am putting up a dry stack stone vaneer. My stove is installed in a corner and i have 8 inches from the existing drywall to the closest corner of the stove. Once i put on the rear heat shield and double walled pipe my minimum clearance according to my manual is 6 inches to combustibles 3 inches to non combustibles. Thanks