Abstract: A self-contained alarm screen apparatus for securing building openings against intruders includes a screen sheet having a screen peripheral edge, a frame secured to the screen peripheral edge for providing structural support to the screen sheet, a conductive detection wire secured across the screen sheet for detecting a breach in the screen sheet, terminals for connecting to the detection wire, alarm elements including an electric power source, an alarm sounder, and an alarm circuit for carrying electric power from the power source to the alarm sounder, and an element mounting structure for mounting the alarm elements to the frame. The alarm elements are preferably joined together by a joining structure to form an alarm module, and the element mounting structure preferably includes a module mounting structure for mounting the module to the frame, and a module connector for connecting the module to the module mounting structure.