Double-Car Garage Door Sizes: 16x7, 18x8 and Reinforcement

Standard double sizes

Nearly every two-car garage built in the last forty years uses one of these openings.

• 15' x 7' — older subdivisions and narrower two-car garages.
• 16' x 7' — the national standard for a two-car garage.
• 18' x 7' — wide doubles, common on newer builds with side entry.
• 16' x 8' and 18' x 8' — same widths with the extra section for tall vehicles.
• 20' wide — custom territory, usually three-car bays or shop buildings.

Reinforcement: struts, gauge and wind load

Width is the enemy of a flat panel. A 16-foot section without support bows in the middle, which strains the center hinges and lets the opener flex the top panel.

• Struts — horizontal steel bracing across sections; the top section needs one for any opener.
• Steel gauge — 24 gauge is builder-grade, 25 to 26 thinner, and heavier gauges resist dents.
• Three-layer construction — the foam core itself stiffens the panel significantly.
• Wind-load rated doors — required in some jurisdictions and useful anywhere with storm exposure.

Springs, cables and openers for doubles

Doubles almost always run two torsion springs, one on each side of the center bracket, so the load is balanced and a single break does not drop the door. Cables must spool evenly on both drums or the door racks and eventually derails. For insulated, wood or full-view doubles we recommend 3/4 HP or a wall-mount jackshaft opener rather than the minimum 1/2 HP.

Symptoms that a double door is out of balance

One side lifting faster than the other, a visible sag along the top section, popping hinges, an opener that hums at the start of travel, or a door that will not stay put halfway open. All of these are balance problems, and all of them shorten the life of every other part. Call (470) 999-6963 for a balance and safety check.

Frequently Asked Questions

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