I built my shed, but do not like the way I did the eves. It is simply 2x4 rafters with 7/16 OSB up flush with the edge. Then I overhung the felt and rolled/nailed asphalt about 1/4 inch. I'm worried about the edge of the OSB getting exposed and swelling. Also, since I nailed the rolled asphalt, the OSB kind of split at the edges in a few places because the nails were close to the edge (1/2 away inch).
Now I am thinking of putting a 1/2 inch facia board up against the ends of the rafters and OSB. Unfortunately, the OSB actually overhangs a few of the rafters a bit, so it will be a rough fit.
After I do that, I have some galvanized flashing (L), but I think that is supposed to go under the roofing material, right? I think my nail are too close to the edge to allow that to slip under.
Use a 1" x 4" and line it up under the edge of the osb board, (Ick), and also weave in a flashing piece called a gutter apon drip edge under your roof material. You may have to remove the lowere edge nails to do this, if they are in the way.
The gutter apron will seal the exposed edge of the bottom of the osb and cover the top edge of the new 1" x 4" fascia board.