I have rain leaking into the top of my window. I cut away some drywall to look up into the wall and it appears that the water may be running down the outside of the builders felt, which terminates at the top of the window, then, instead of being diverted around the window and down to the weep holes in the brick facing, it has found a seam where the drywall meets the window frame and is running into the house there. Is this a flashing problem? How can I repair it? The house is 13 years old. This is the only window that has this problem.