20 feet wide · 8 feet high · oversize
20x8 garage door
A wide double for a three-car garage's main bay.
Where it comes from
Why an opening is 20x8
The wide bay of a three-car garage, where two openings were merged into one, or a shop built for width rather than height. Twenty feet at eight feet high is a lot of door on a house.
Two vehicles with a great deal of room, or one vehicle plus the space to get a trailer in beside it. Eight feet of height keeps it to normal road vehicles.
Fitting one
What changes at 20x8
Twenty feet of span with only eight feet of height means a wide, comparatively shallow door that wants proper strutting to stay flat. The header is the job. Everything else follows from getting that right.
The opener. Commercial or heavy-duty residential. The weight of twenty feet of insulated steel is beyond what a hallway opener is built for.
Getting hold of one. Order only. Expect it to come from a commercial line and expect the hardware to be quoted separately.
The mistake
What people get wrong about a 20x8
Merging two 9x7 openings into one twenty-foot opening without an engineer. Removing the pier between two doors removes the thing holding the roof up over that span, and that is not a door decision.
What it costs
A 20x8 door, installed
| Material | Typical, installed | Worth knowing |
|---|---|---|
| Sectional steel | $6,390 | The baseline, and most of the doors on most streets. |
| Insulated steel | $7,140 | Worth it on an attached garage or one with a room above it. |
| Steel overlay, carriage look | $9,640 | The swing-door look on a sectional door. Where the price starts climbing. |
| Wood overlay | $21,740 | Real wood over an insulated core. Beautiful, and it needs refinishing. |
| Aluminium and glass | $14,990 | Modern, lots of daylight, lower insulation value. |
The gap between the cheapest and dearest 20x8 is $22,620, and not one dollar of it is the size. Same opening, same fitting, same morning — what moves the number is the model: panel style, insulation and overlay. Why a door costs what it does →
National guide ranges, checked September 2026, not a quote — what moves the number.
That is the door, the tracks, the springs, fitting it and taking the old one away. An opener, a keypad and any work on the opening itself are separate — what is in a quote and what is not.
Before you book it
What the extras cost · why nobody should touch their own springs
Framing
Rough opening for a 20x8
20'0" × 8'0"
For a sectional door the rough opening equals the door size exactly. A 16x7 door needs a 16'0" wide by 7'0" high finished opening.
Fits
What goes through a 20x8
- Compact car (Civic) — 13.2' spare across the mirrors
- Sedan (Camry) — 13.0' spare across the mirrors
- Small SUV (RAV4) — 12.9' spare across the mirrors
- Large SUV (Suburban) — 12.5' spare across the mirrors
- Full-size pickup (F-150) — 12.0' spare across the mirrors
- Cargo van (Transit) — 11.9' spare across the mirrors
- Pickup, tow mirrors (F-250) — 11.2' spare across the mirrors
Two side by side: compact car (civic), sedan (camry), small suv (rav4), large suv (suburban), full-size pickup (f-150), cargo van (transit), pickup, tow mirrors (f-250).
Questions
20x8 garage doors, answered
How much does a 20x8 garage door cost?
A 20x8 in sectional steel runs about $4,630 to $8,150 installed, and $5,230 to $9,050 insulated. That is the door, the tracks, the springs, fitting it and taking the old one away. An opener is separate.
What is the rough opening for a 20x8 garage door?
20 feet by 8 feet, exactly. For a sectional door the rough opening is the door size — framing it wider leaves a gap the seal cannot close.
How much clearance do you need for a 20x8?
12" of headroom above the opening for a standard torsion setup, 9" front, 4.5" rear of sideroom each side for the vertical track, and the door height plus 16 inches of backroom. The full table, including low-headroom kits, is on the rough opening guide.
Is a 20x8 a residential or a commercial door?
Residential by address and commercial by every other measure. At 20 feet the sections, the track, the shaft and the operator are all heavier-duty parts, the header is a structural design question rather than a bigger beam, and it is usually quoted through a commercial product line. Pricing it against a 16x7 compares two different things.
Is a 20 ft garage door big enough for two cars?
Two of these, comfortably: compact car (civic), sedan (camry), small suv (rav4), large suv (suburban), full-size pickup (f-150), cargo van (transit), pickup, tow mirrors (f-250). Anything wider across the mirrors gets tight — measure yours, mirror to mirror, before you decide.
How long does it take to fit?
Four to six hours, plus an hour or two to take the old one away. Plan on losing the morning.
What opener does a 20x8 need?
Commercial or heavy-duty residential. The weight of twenty feet of insulated steel is beyond what a hallway opener is built for.
Is a 20x8 a stock size?
Order only. Expect it to come from a commercial line and expect the hardware to be quoted separately.
Other sizes