Steel Garage Doors: Gauges, Layers, Coatings and Dents

Gauge: what the number means

Gauge measures thickness, and lower numbers are thicker. Builder-grade doors are often 25 or 26 gauge, which dents from a basketball. Better doors use 24 gauge; premium and commercial-influenced doors go heavier still.

• 26 gauge — thinnest, lightest, most dent-prone; typical of bargain doors
• 25 gauge — common builder grade
• 24 gauge — good residential standard, noticeably stiffer
• Heavier gauges — premium and commercial doors, best dent resistance

Layers and insulation

Layer count drives quietness, stiffness and R-value more than gauge alone.

• Single layer: R-0 to R-2; loud, flexes visibly on wide doors
• Two layer with polystyrene: roughly R-6 to R-10
• Three layer with polyurethane: roughly R-12 to R-18+, stiffest and quietest
• A foam core also bonds the skins, which is why insulated doors resist dents better

Coatings, rust and paint

Quality steel doors are hot-dipped galvanized, primed and baked with a polyester or premium finish, which is why factory paint outlasts a repaint. Rust starts where the coating is broken — scratches at the bottom section, string-trimmer nicks, and drilled holes for hardware. Touch up chips promptly and rinse the door a few times a year to keep pollen and grit from holding moisture against the skin.

Dents: repair or replace the section?

Shallow dents in the flat area of a panel can sometimes be pulled or blended, but pressed pattern lines rarely return to shape. Because sectional doors are modular, replacing a single dented section is usually the honest fix — we match the profile and color as closely as the model allows, transfer the hinges and re-balance the door.

Frequently Asked Questions

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