1. Firstly, the garage door surface that will be repainted must be properly prepared for painting. A proper, deep clean before painting can be done using common household materials.

   
   Option 1 Cleaner:
   1 cup laundry detergent to 5 gallons of warm water.
   Laundry Detergent: Any household detergent may be used to prep your garage door for painting. Use a laundry detergent that has less than 0.5% phosphate. Mix 1 cup laundry detergent with 5 gallons of warm water. Do not use a blend of detergents and do not use detergents with bleach.
   
   Option 2 Cleaner:
   1 cup household ammonia to 5 gallons of room temperature water.
   Household ammonia may be used as another option for cleaning your garage door and preparing it for repainting. Be sure to use room temperature water.
   
   

2. Using either option of cleaning solution use a well-soaked cloth, sponge or very soft bristled to wash the garage door. A low-pressure spray washer can also be used. Once the door is washed, rinse well with clean water to eliminate the possibility for any leftover residue on the door that could interfere with painting.
   
   
3. If you encounter minor imperfections such as small scratches that have NOT left the metal substrate exposed, they can be lightly sanded or buffed to create a smoother surface. Be careful not over-buff the surface, you do not want the metal substrate exposed as this can increase the chance of rusting.
   
   
4. Any exposed metal but be treated to prevent rusting. If there is exposed metal on the garage door, lightly sand the area and apply a primer specifically designed to protect any exposed galvanized steel from rust/corrosion.
   
   
5. After the door has been cleaned and any imperfections and exposed metal has been addressed, it is time to paint! Painting must be done within 24 hours with a high-quality latex exterior house paint.  Ensure paint is mixed well – mechanical mixing is recommended to assure that no settling on the bottom of the container remains.  Apply uniform coat at the manufacturer’s’ recommended dry film thickness.

Garage Door Painting Tips: Garage door must be completely dry before painting. Painting should be done early in the morning. It’s best to avoid painting when temperatures are below 50 degrees F.

 *Above instructions are a general summary of proper painting practices and does not cover all aspects of repainting steel garage doors.