Commercial Sectional Door: Construction, Track Types and Vertical-Lift Doors

What a commercial sectional door is

DASMA’s terminology defines a commercial door as a door intended for vehicular use at entrances of commercial buildings, and a sectional door as two or more horizontal sections hinged together, capable of closing the entire opening, operating by means of tracks and track rollers ⁴.

Put together, that is the familiar overhead door on warehouses, fire stations, auto shops, farm buildings and loading bays.

Compared with residential doors, commercial sectional doors are usually wider and taller, use heavier sections and hardware, run on 2-inch or 3-inch track, and carry more struts. Clopay’s commercial manual, for example, gives separate hardware sequences and clearances for 2-inch and 3-inch track ⁹.

How it works

The sections are hinged at each joint, with graduated end hinges holding rollers that run in vertical and horizontal track.

Torsion springs on a shaft above the opening counterbalance the door through cable drums, so a motor operator, chain hoist or a person can move it.

As the door opens, the sections roll through the track radius and hang under the ceiling, or on high-lift and vertical-lift doors, travel further up the wall.

Wide commercial doors use reinforcing struts across the sections. Clopay’s manual explains how struts attach to end and center hinges and that the number of struts is shown on the hardware box and wind load drawings ⁹.

Lift types

Example: headroom by lift type (one maker’s manual)

Clopay’s commercial sectional manual lists the space needed above the opening for different track setups ⁹.

Clopay adds that doors over 18 ft high, over 1,000 lb springing weight or with high-cycle springs may need more headroom and sideroom, as do doors with more than one row of springs or with chain hoists and operators ⁹. See headroom.

Vertical-lift commercial doors

DASMA defines vertical lift as a hardware design that causes doors to open vertically where no horizontal tracks are required, and a vertical lift drum as a cable drum with changing-radius grooves that negates spring tension ⁴.

The door rises straight up the wall above the opening, so the ceiling stays clear for cranes, lights, sprinklers, racking or overhead conveyors.

The trade-off is height. Clopay’s commercial manual lists headroom for a vertical lift door as door height plus 12 inches, and notes that vertical lift doors with a straight incline need additional headroom ⁹.

DASMA also defines an A-frame as a support used to fasten the torsion spring assembly of a vertical lift door to the wall ⁴.

For buildings with plenty of height, vertical lift is often the cleanest layout; for dock doors DASMA recommends vertical or high-lift track to maximize warehouse space where geometry allows ⁶.

Where commercial sectional doors are used

Warehouses, distribution centers, loading docks, auto service bays, fire and ambulance stations, municipal garages, farm buildings and car washes. Insulated versions separate heated or cooled spaces; full-view versions with aluminum and glass sections serve showrooms and restaurants.

In fire stations and service bays, doors may cycle many times a day and need fast, reliable operators and high-cycle springs; in storage buildings they may open only a few times a week.

DASMA lists sectional doors among the main dock door types, alongside rolling, high performance and sheet doors ⁶. See loading dock door.

Wind and thermal performance

Large commercial doors catch a lot of wind. DASMA’s guidance on vertically reinforcing sectional doors covers added reinforcement for wind loads ¹, and its gauge chart notes structural performance is best determined by testing to ANSI/DASMA 108 ². Local codes and the authority having jurisdiction set the required performance ⁶.

For energy, DASMA’s Thermal Performance Verification Program covers sectional doors, with U-factor tested to ANSI/DASMA 105 ⁷. DASMA lists panel material and thickness, door-to-jamb seals and the section interface as design factors for thermal performance at dock doors ⁶.

Operators and jackshafts

Commercial doors are commonly driven by trolley operators, jackshaft operators that turn the torsion shaft, or manual chain hoists.

Clopay’s manual warns not to install jackshaft openers on doors with standard lift or low headroom track ⁹, and DASMA’s guidance on jackshaft operation of standard-lift doors explains the cable-tension issues involved ⁸.

High-use doors need operators and springs rated for the real cycle count.

DASMA defines a high cycle spring as a counterbalance spring with increased cycle life capability for high usage doors ⁴, and a door that cycles dozens of times a shift will wear through standard springs quickly.

Section construction and foam rules

Commercial sections come as single-skin ribbed steel, insulated sandwich panels, aluminum full-view sections and sometimes wood. Insulated sandwich sections are common where a building is heated or cooled; aluminum and glass sections where daylight or display matters.

Foam rules are stricter on commercial buildings.

DASMA explains model codes require foam plastic in garage doors to be covered with at least 0.125 in wood, 0.010 in steel or 0.032 in aluminum, or the complete door tested to ANSI/DASMA 107, and that only doors on one- and two-family dwellings are exempt from that requirement ³.

A commercial insulated door therefore needs compliant facings or a passing ANSI/DASMA 107 test.

Jambs, headers and wind forces

A big door is only as strong as what it hangs on.

DASMA’s sheet on connecting garage door jambs to building framing says connecting doors to framing is as important as the design of the doors themselves, gives connection schedules for anchors, lag screws, nails, welds and self-tapping screws, and advises professional engineering advice so wind forces can be withstood by the structure and the door ⁵.

Clopay’s manual adds that track installations must use sway braces on rear track hangers so tracks cannot spread and let the door fall ⁹. These details are why commercial installation is a job for trained door installers working from the maker’s instructions.

Living with a busy door

In busy facilities the door gets hit. Forklifts, trucks and carts strike bottom sections and tracks, and DASMA’s dock guidance suggests breakaway designs, impact-resistant guides and easily replaced clips, seals and brackets where impacts are frequent ⁶.

Bollards protect the door, as long as they do not interfere with locks or wind reinforcement ⁶.

Counterbalance matters too: DASMA says a dock door should not drift into the opening where vehicles can hit it ⁶. A door that drifts needs a technician to adjust or replace the springs before it is struck or falls.

Pros and cons

Limits

Sectional doors are not fire doors; DASMA says they are not intended for fire-rated walls ³. Where overhead space or room depth is very limited, DASMA suggests a rolling door instead ⁶. And clearances grow with size, weight and spring count ⁹.

What drives cost

No prices on this page. See the cost guide.

• Size and section construction.
• Lift type: high and vertical lift need more track and hardware.
• Wind rating and struts ¹.
• High-cycle springs and operator.

How to specify a commercial sectional door

1. Measure the opening, headroom, sideroom and backroom ⁹.
2. Choose the lift type to fit the building ⁴.
3. Set insulation, wind and cycle requirements ^{7 1}.
4. Choose the operator type; avoid jackshafts on standard or low-headroom track ⁹.
5. Confirm jamb and header framing can carry the door ⁵.

Upkeep

• Follow the maker’s maintenance schedule.
• Inspect rollers, hinges, cables and track regularly.
• Use sway braces on rear track hangers, per the maker ⁹.
• Leave spring and cable work to a trained technician ⁹.

Warning signs

Frayed cables, a door that drifts, tracks spreading, impact damage, or a section pulling from its hinges need prompt service. Clopay’s manual warns that springs, cables and bottom brackets are under extreme spring tension and that a damaged door or track can be hazardous to operate ⁹.

Standards

Wind performance is tested to ANSI/DASMA 108 ²; U-factor to ANSI/DASMA 105 ⁷. Jamb connections to building framing are covered in DASMA TDS-161 ⁵. Local building codes govern.

Commercial vs residential sectional door

Myths

Myth A commercial door is just a big garage door.

Reality Track, springs and struts differ ⁹.

Myth Any opener fits any door.

Reality Not jackshafts on standard-lift track ⁹.

Myth Sectional doors can protect fire walls.

Reality DASMA says they cannot ³.

Climate

Bottom line

Pick the lift type for the building, size hardware for weight, wind and cycles, and keep counterbalance work with technicians. See track lift type.

Related terms

Loading Dock Door

A loading dock door is a door serving a loading dock, giving access to a parked transport vehicle so goods can be loaded and unloaded, usually as part of a system with a dock leveler, seals or shelter, bumpers and vehicle restraints.

High-Speed Roll-Up Door

A high-speed roll-up door is a non-swinging, power-operated industrial door with an automatic closing device that opens at least 32 inches per second and closes at least 24 inches per second, used on busy vehicle and material-handling openings.

Track Lift Type

Track lift type is the shape of the track a sectional garage door rides in, which sets the path the door takes as it opens: turning back under the ceiling early, late, or not at all.

High-Lift Track

High-lift track is garage door track with extended vertical sections that make the door rise straight up some distance above the opening before it curves back into the horizontal track.

Sectional Garage Door

A sectional garage door is a door made of two or more horizontal sections hinged together that ride on rollers in side tracks, bending through a curve to rest flat under the ceiling when open.

Roll-Up Garage Door

A roll-up garage door is a vertically operating door whose curtain of interlocking slats or corrugated sheet coils around a barrel or axle above the opening when it opens, instead of sliding back under the ceiling.

Also referenced from: Sectional Garage Door, Roll-Up Garage Door, Opener Duty Cycle, Track Lift Type, High-Speed Roll-Up Door, Fire-Rated Rolling Door, Counter Shutter, Loading Dock Door, Vision Panel