How to Prevent Mold and Mildew Buildup on Exterior Doors

How to Prevent Mold and Mildew Buildup on Exterior Doors

From rain and sleet to debris and critters, exterior doors serve as the first line of defense for our homes. Unfortunately, that exposure to the elements comes at a cost. A build-up of mold, mildew and other “gunk” is a common problem for exterior doors, especially those that are located in shaded areas or especially humid climates. 

Mold and mildew don’t automatically mean you need a new door, but it does require action. If left unattended, mold and mildew can lead to more lasting damage—not to mention its unsightliness. Ahead, find out everything you need to know to form your plan of attack against mold and mildew. 

How Mold & Mildew Build Up (And How to Prevent It)

Moisture, lack of ventilation, and organic matter create a breeding ground for mold and mildew. Sunlight and the chance to fully dry out after a rain is key in mold prevention, which is tricky if you live in a humid area or your doors are not in direct sunlight. The initial concern will be how mold and mildew mar the appearance of the door, but—if left unchecked—it can gradually contribute to rot.

The number one prevention tactic for fungal growth is to simply clean and treat your exterior doors regularly. If you don’t already have mold growth, consider a coat of a mildew-resistant stain blocker and primer. (Be sure to check your door material and paint/finish type before you apply!)

mildew and mold on exterior door

How to Clean Mold & Mildew Off Exterior Doors

When dealing with mold and mildew on exterior doors, it’s important to handle the problem sooner rather than later. Follow these steps:

  1. Protect yourself. Mold spores can float in the air and damage lungs, so it's smart to wear rubber gloves and a face covering.
  2. Grab your supplies. You'll need a long-handled brush, towels, a water hose, and two empty spray bottles. In one bottle, make your Bleach Solution and in a separate bottle, make a vinegar solution. (Recipes below.)
  3. Douse your door with water, and give it a light scrub to get the dirt and grime off.
  4. Next, use your Bleach Solution. Spray directly onto the door, concentrating on the corners and any areas with visible mold/mildew. Let it sit for about 15 minutes. Scrub, then rinse thoroughly with water.
  5. Option: Follow up with your vinegar spray bottle. Spray directly onto the door, focusing on the moldy areas. Scrub gently with a brush and rinse thoroughly.
  6. Rinse well with a water hose, then dry thoroughly with a clean towel. If you have a box fan, blow it directly on the door until it's completely dry.

Vinegar Solution: Mix equal parts white vinegar and water.

Bleach Solution: Mix one part bleach with four parts water.

*Note: Many commercial mold cleaners are available at your local hardware store. Be sure to follow the instructions carefully and consider your paint type before you start. 

cleaning exterior door

For more detailed instructions on cleaning your door according to your specific door type, head to this blog post.

Get Into a Maintenance Routine

Prevention is always better than cure, so it’s smart to stay on top of your exterior door maintenance before mold and mildew become problematic. By implementing a regular maintenance routine, you can prevent fungal buildup and subsequently prolong the life of your door. 

A good rule of thumb is to give your doors a once-over at least twice a year—say, once after the snowy/rainy season, and once when the hot, humid days of summer start to wind down. Pay close attention to areas prone to mold and mildew growth, such as the bottom and corners. Look for any signs of discoloration, musty odors, or soft spots on the door's surface.

signs of mold and mildew on doors

PRO TIP: To improve ventilation, make sure there are no shrubs or plants obstructing your door’s airflow. 

Remember, early intervention is key to nipping mold/mildew in the bud and maintaining a beautiful doorway. But if your door does fall victim to rot, you know where to find a new one.