1. Size the Window Code minimum is a window 20 inches wide and 24 inches high with a total clear area of 5.7 square feet—which actually translates to a 20-inches-wide-by-41-inches-high or a 35-inches-wide-by-24-inches-high unit. Awning hung or sliders are best. Also, the windowsill must be 44 inches or less from the basement floor.
2. Size the Well By code, the total clear area of the well must be at least 9 square feet with a 3-foot or more area between the window and the far edge of the well opening. Enclose the well with a shell. A hinged cover must be able to be opened or removed from either side without special tools.
3. Ladder Window wells more than 44 inches deep need a permanently attached ladder or steps, which can project into the well no more than 6 inches. Most ladders are welded to or molded into the shell enclosure.