How to Remove Mildew from a Wooden Window Frame

The wooden frame of a wet window is covered in mildew growth.
  • 40 hours
  • Intermediate
  • 1
What You'll Need
Laundry detergent
Hand gloves
Spray bottle
Sponge cloth
Steel wool
Antifungal paint

If left untreated for a long period of time, mildew can lead to the deterioration of a wooden window frame. Therefore, taking the time to remove the mildew is a crucial step if you want your frames to last. Mildew can cause other complications as well, such as triggering allergic reactions in some of your family members or contributing to respiratory problems and other illnesses in children and people in the household who have weaker immune systems. Cleaning should be undertaken once in a while not only for housekeeping purposes but to ensure the good health of your loved ones.

Removing mildew is fairly easy. You can finish the task within just a few minutes.

Step 1 - Prepare the Cleaning Solution

Pour a capful of laundry detergent, a quarter cup bleach, and warm water into a large bucket, and mix them thoroughly. Put on gloves to protect your hands as well.

Step 2 - Get Close to the Window Frame

You'll need to get yourself as close to the window frames as possible, so if the windows are situated in a high, hard to reach area, use a stepladder. Have a spotter at the bottom of the ladder if you be up particularly high, and take care not to fall while cleaning. If the window frames are detachable, take them down and clean them on a level floor.

Step 3 - Apply the Solution to the Affected Areas

Fill a spray bottle with the cleaning solution from the bucket and spray the mildewed areas thoroughly. Allow the solution to soak the wood for at least a few minutes. This will help soften the mildew and allow for easier cleaning. After it's sat, scrub the area with a sponge, working from the edges towards the inside. Rinse thoroughly with clean water when you're finished, and leave it to dry for a few minutes.

Step 4 – Disinfect the Mildewed Area

Get a spray bottle again but fill it with strong bleach this time. By strong, we mean that it should not be diluted with any amount of water. Spray it onto the dry infected areas to kill all the remaining mildew in the wood. Rinse with soap and water.

If there are still signs of growth, scrub the wood gently with a steel wool or sandpaper. Be extra careful not to scratch or incur any damage to the surface.

Step 5 – Let the Wooden Window Frames Dry Completely

Wipe the frames with a clean dry cloth or dry sponge to absorb any remaining liquid or moisture on the surface. Let it air dry the rest of the way afterward. It is important that no amount of moisture is left on the surface as this will only encourage new mildew growth.

Step 6 – Apply Antifungal Paint

Coat the cleaned wooden window frames with a matching stain or paint that has antifungal properties. This will help keep mildew from re-growing. You may also apply varnish. This will allow your frames to remain clean and looking new.

Check your windows every now and then to be sure the mildew isn't coming back. If you notice signs of new patches developing on the surface, treat them immediately. Don’t wait for it to get out of hand; cleaning mildew during its earliest stage of development helps make removal that much easier.