I have a house with a peaked roof that on one side comes down to a flat roof. The flat roof is 10 wide, the entire width of the house and it is an old addition. I am going to raise the outside wall of the flat roof 2 feet and then frame over to the peak, but about 3 feet down from the peak. I plan to cut holes in my existing sloped roof next to each of the existing 2x4’s and stick the 2X6’s through the attic, over to the other side of the peak and then nail the 2X6’s to the existing 2X4’s in the attic on both sides. I like this idea better than nailing a 2X8 to the existing roof and then working off that to the new 2’ high wall. I don’t know why, it just seems like it would be stronger than working off a nailed header.
But, here’s the real question, after you put up your 2X6 joists and your ready to put on your 4’X8’X7/16" OSB board do you have to put down 1X8’s or 1X10’s down first before your OSB or do you just put the OSB right on the joists with the metal clips between the sheets to help hold them level together. I’m used to old house construction and they always have 1" boards under the OSB and then shingles.
Thanks in advance for your help.