How To Get Rid Of Mold On Wooden Window Sills

If you have a window in a highly humid or moist area, check for mold growth on the window sill. Mold thrives on windows in a moist environments like a bathroom, which could eventually cause wood rot. Mold also increases your risk of developing health problems so it is best not to delay getting rid of it. Here are some tips on getting rid of mold on window sills.

Prepare the Area

For this project, you will need: 

  • breathing apparatus or dust mask
  • safety gloves
  • old cloths
  • a cleaning agent like bleach vinegar, or ammonia
  • nylon brush
  • sandpaper
  • primer
  • paint
  • paint brush
  • trash bag
  • pail
  • tarp

Try to work on a sunny day so the mold will dry faster on the wood. Open the window to dry out moisture, and to help get rid of hidden mold patches by making them fall out the window.

When working with mold, wear a breathing apparatus to keep from inhaling toxic mold spores, and wear gloves. If anyone in your house has mold allergies or asthma, wait until they are out of the room to work. Lay tarp around the window area to prevent mold spores from getting in the floor.

Make the Bleach Solution

Wearing gloves, combine three parts warm water with one part of bleach, ammonia, or vinegar. Scrub the area with the nylon brush, wiping away extra moisture with the cloth, and then allow the area to dry before you shut the window. For an unpainted window sill, remove any remaining mold stains with sandpaper. If the window sill is painted, you will have to sand, prime, and repaint. Vacuum to remove the dust from sanding.

Try to use paint with anti-fungal properties to prevent mold from coming back. Fold the tarp inward and discard it. Dip any reusable items that came in contact with mold in bleach and water to disinfect them, and wash clothing right away to prevent spreading of spores.

Prevent Future Mold

To prevent mold, set up exhaust fans in areas with high humidity like kitchens and bathrooms, and run humidifiers for shorter time periods. Decrease the number of plants in one room, since they cause more moisture. If you must have plants, choose ones with low humidity. Apply caulk around the window edges to stop leaks and remove condensation.

You should be able to remove window sill mold yourself. Check windows periodically to watch out for returning mold growth. If the mold keep returning or it covers a large area in your home, contact a mold remediation service. For more information, visit or a similar website.