If you own a home with an exterior steel door, you are likely relieved that you don't have to worry about security with regards to the strength of your door. However, one problem that you might not have considered is that of mildew forming on your door. Here are some tips for fixing this problem and keeping it from happening again in the future so that you don't have to deal with it.

1. Clean the Existing Mildew Off the Door

The first thing that you need to do is get the existing mildew off the door. You might have started to smell it over the past few days. Your first step is to take a several gallon bucket and fill it with water. This water should be anywhere between room temperature and lukewarm. Once you have the bucket filled with two gallons of water, you then add ammonia. You should add a fifth of a cup of ammonia for every gallon of water that you are working with, so in this case you need two-fifths of a cup of ammonia. Use a broom handle to mix the ammonia and the water together.

Once the solution has been fully mixed, put gloves on to protect your hands. Then, dip a sponge to the solution. Wash the entirety of the steel door. Do not focus on just cleaning the parts where you see mildew because it could be anywhere on the door and you just might not be able to see it yet. Continue washing one side of the door until it is completely covered in a  layer of the solution. Move onto the other side of the door and do the same thing. Use a low pressure hose to rinse off the rest of solution. Dry using a soft towel.

2. Add a Protective Coating

To prevent mildew in the future, you can either wash the door down once a month using the methods mentioned above, or you can add a protective coating to your door that will make it much more resistant to moisture. This will help prevent mildew from forming over time and will allow you to avoid having to think about mildew on your steel door.

For more information, talk to a company that specializes in metal doors. They will likely have a coating that they will recommend, and they can offer more cleaning tips as well.