I have 2 story house in Florida that is concrete block on the 1st floor and wood frame on the second floor. I am residing (rain screen) the second story of my house and discovered that the current sheathing on the house is 3/8, which does not meet code for my wind zone. While the siding is off, I plan to resheath the house by going over the old sheathing with 5/8 zip wall. I have 2 walls are in contact with the 1st story roof at the bottom of the wall. Currently both wall are flashed with a 4×6 L flashing. Is there a good way to flash this without removing that area of the roof? Can I just bring the zip wall down to an 2 inches above the roof deck and cover is prosoco r guard and use a z flashing at the bottom of the sheathing? Any other ideas?