Garage doors have a baked on finish that will last many years. Garage door finishes need to be cleaned regularly, most manufacturers recommend a yearly washing. Dirt and oxidation can build up on your garage door over the course of time and this annual washing will keep your garage door looking its best and increase the life of the garage door finish.
When washing the garage door, use one cup of nontoxic/biodegradable cleaner mixed with two gallons of warm water. Working from the bottom panel up, wash the steel garage door with a cloth or sponge soaked in the cleaning solution. If the door is very dirty or mildew stained you can also use a very soft bristled brush. You may also choose to use a pressure washer at a very low pressure setting.
Do not use abrasive cleaners or abrasive cleaning pads as these can damage the garage door finish.
If washing does not remove mildew stains you might try mixing one cup of household bleach with 5 gallons of water and one cup of mild liquid soap.
Once you have finished washing the garage door, rinse completely with clean water, making sure no soap or cleaning residue is left, as this can damage the finish.
If you decide to repaint your steel garage door it is important to first clean the garage door following the steps listed above. Once the garage door is cleaned, look for any scratches or imperfections in the surface. Lightly sand or buff the imperfections be careful not to expose bare metal.
If the garage door was installed in the past 2 years, then you will want to be sure you remove any wax remaining on the door from the factory. To remove any remaining wax, use steel wool or synthetic steel wool equal to “000” soaked in soapy water.
Make sure the garage door is completely dry before painting, using a high-quality exterior latex paint. Do not use oil based paint over factory finishes. Avoid painting at temperatures below 50 degrees F.