Sectional Garage Door

A sectional garage door is a door built from several horizontal panels, called sections, joined by hinges. Rollers on the hinges ride in a track on each side of the opening, so the door bends at each joint as it rises, turns through the curved track and comes to rest flat under the garage ceiling. It is the most common style of garage door on homes and is widely used on shops and warehouses too.

How a sectional garage door works

The door runs in two tracks. The vertical track holds it straight up the sides of the opening, and the horizontal track carries it back along the ceiling once it is open. A counterbalance system carries most of the door's weight, so it should feel light when you lift it by hand. Most sectional doors use a torsion spring on a shaft above the opening; some older doors use extension springs along the horizontal track. Lifting cables run from the spring drums to the bottom corners of the door.

The parts of the door itself

A typical home door has four or five sections stacked one above the other. Each section has an outer steel skin, and an insulated door adds a foam core and often an inner steel skin, known as sandwich construction. Vertical stiles stiffen each section, and a strut is bolted across the top section, or across more of them on a wide door, so it does not bow under wind or the opener's push. The bottom section carries the bottom seal and the brackets for the lifting cables. DASMA, the trade group for door makers, publishes a standard list of these part names in TDS 160.

Sectional vs one-piece and rolling doors

A one-piece (tilt-up) door is a single rigid slab that swings out at the bottom as it opens, so it needs clear space in front of the garage. A sectional door goes straight up and back, so a car can park close to it and the driveway side stays clear. A rolling steel door coils its slats into a drum above the opening and is common on commercial buildings with little room above the door. Our sectional vs rolling steel guide compares those two for a business.

Room the door needs

A sectional door needs space above the opening for the spring and the track's curve, called headroom, and depth along the ceiling for the open door, called back hang. Where headroom is short, a low headroom track kit fits the door under a lower ceiling. Where the ceiling is tall, a high-lift track runs the door further up the wall before it turns.

Can you buy sections of a garage door?

Often, yes. Because each section is its own panel, one dented section can be swapped while the rest of the door stays in place, as long as the maker still builds that model in the same size and style. G Brothers does this as garage door panel replacement when the rest of the door is sound.

What is the wood around a garage door called?

The boards along each side of the opening are the jambs, and the board across the top is the header. The track brackets fasten to the jambs, and the jamb seal that closes the gap between the door and the frame is fixed to them as well.

Sectional door installation in Lakewood and Denver

G Brothers installs new sectional doors for homes across the Denver metro from our Lakewood shop, with the track and springs set up for the door's size and weight. See garage door installation for the styles and brands we fit. For a shop, warehouse or service bay, commercial garage door installation covers sectional, insulated and rolling steel doors. Industry standards behind these doors, such as ANSI/DASMA 109 on cycle life, are published by DASMA, with part names in its technical data sheets.