How to Fix a Rusting Bottom Panel on a Garage Door

Garage doors provide homeowners with easy access to their garage while still protecting cars against the harsh outdoor elements. Vendors and suppliers sell garage doors in a multitude of models and veneers to match the design theme of most types of houses, but many garage doors are of the common galvanized steel variety. The salt used to maintain roads in the winter can actually corrode the protective zinc barrier of galvanized garage doors, exposing the steel underneath. This results in rusting bottom panels on garage doors and should be repaired as soon as the damage is evident.

The bottom panels of garage doors are prone to rust damage.

Step 1

Remove the garage door's power source prior to repair. Unplug the power cord for the door or switch off the garage's power at the building's circuit breaker.

Step 2

Apply dish detergent to the rusted panels. Scrub the rusted areas vigorously with a soft brush.

Step 3

Clean the detergent and rust from the door using a rag dampened with warm water. Examine the door for remaining rust damage.

Step 4

Sand any remaining rust with a coarse-grit sandpaper until all rust is removed. Start with a coarse-grit sandpaper, and then switch to a fine-grit sandpaper if a smoother finish is desired.

Step 5

Apply a rust-inhibiting primer to the repaired areas. Check that the primer is compatible with steel and rated for outdoor use. Zinc chromate-based primers are a common outdoor metal primer. Allow the primer to dry.

Step 6

Paint the repaired area to match the existing garage door color and gloss. Allow the paint to dry, then restore power to the garage door.