Door Section

A door section is one of the horizontal panels that make up a sectional garage door. Sections are manufactured in standard heights, typically 21 inches for residential doors, so a standard 7-foot door uses four sections. An 8-foot door typically uses four 24-inch sections, depending on the manufacturer.

Each section is a self-contained structural unit. It consists of an outer steel skin, optional insulation, and in insulated models an inner steel backer (called sandwich construction). Horizontal rails run along the top and bottom edges, and vertical members called stiles run up each side and at mid-span. Together, rails and stiles form the structural frame of the section.

Sections connect to each other through hinges. The hinges bolt to the meeting rails where sections overlap and allow each joint to pivot as the door bends through the curved track. On most residential doors, a bottom section, two or three middle sections, and a top section make up the full door.

How sections are replaced:

Individual sections can be replaced without buying a complete door, which is a major advantage of sectional construction. A single impact-damaged section from a car backup can often be sourced from the manufacturer and swapped in a few hours. The main constraint is availability: door manufacturers typically discontinue section profiles after 15-20 years, so older doors may require a full replacement when one section is damaged.

The bottom section carries the astragal weatherseal and the bottom brackets for the lift cables. The top section is the attachment point for the opener's J-arm connection plate. Middle sections carry the center and edge hinges that guide the rollers in the track.