It's easy, just add lumber on top or bottom, depending on if it's too low or high. Add same width as wall framing and nail to top or bottom. After you reach desired opening, this may require some plywood to get close enough, about 1/4" bigger than window. Keep it very square. Then on outside patch in sheeting right up to opening edge. This is the most important part of having a square and level window and trim, just check it good. Best of luck to ya....
See my work-Check out my album. "Git 'Er Done":D
Last edited by triple D; 03-19-2008 at 10:30 AM.