How to Remove Mold From Window Sill

  • Everything looks perfect. You’ve got a new fanciful carpet, a super comfy sofa that cost a million bucks, and new curtains that couldn’t be more appealing. Yet, you notice a window mold coming up again over and over, even though you try to get rid of it with plenty of clever, proven methods.  
  • Mold is a fungus that grows in damp areas of your home, such as windowsill or shower walls. Because of condensation, mold will appear quickly when a piece of wood, plastic, or glass is placed near the damp area. Even this cute plant that is supposed to decorate your window can transfer mold spores through the air straight to your window sills.
  • This article shares a couple of mold-related tips, from identifying the mold from the root cause to getting rid of moldy surfaces on your windows to how not to create a perfect environment for mold growth.

Window mold—what you need to know

A window sill is also known as a window ledge or window bottom, and it’s a shelf-like, flat piece of the window trim located at the base of the window. It serves to support and hold the window in place structurally.

You knew that, didn’t you?

In fact, we’re here not to talk about window sills but about mold issues (especially mold removal). 

The essential part of knowledge about mold, a large and taxonomically diverse number of fungal species, is that it can be harmful to humans. 

Mold on window sills, as much as everywhere else, can cause health problems in humans. 

Molds produce irritants and allergens, i.e., substances that can cause allergic reactions—explains EPA

More sensitive individuals can experience allergic reactions when inhaling or touching mold or getting in contact with falling mold spores.

The most susceptible to the effects of mold are:

  • newborns, 
  • children, and 
  • elders;

Mold is not only harmful to people’s physical and mental health, slowly damaging lungs, skin, and the nervous system, but it’s detrimental if you already suffer from respiratory infections or asthma. 

Black mold produces a musty odor, and we can find it across paint, plaster, and wallpaper. 

Black mold spores spread in the air can contribute to:

  • asthma, 
  • allergic reactions, 
  • breathing trouble;

Medical News Today reports that, based on current research, black mold exposure is no more dangerous than any other type of mold exposure. 

All in all, mold is a health hazard and should, therefore, be expunged as fast as possible.

Mold releases toxins, a poisonous gas known as mycotoxins. 

Important: The adverse health effects of mycotoxins range from acute poisoning to long-term effects such as immune deficiency and even cancer.

House mold also releases carbon dioxide as it grows. It consumes oxygen and releases carbon dioxide (CO2). Therefore, if there is a CO2 spike in the room, mold activity will likely increase.

Yet, not only is mold very common in households, but it’s almost impossible to avoid exposure to it since the spores are almost everywhere around us. 

While window sills make for an ideal environment to create mold issues, window frames and walls aren’t free of this threat. 

Important: In some circumstances, mold is beneficial. Mold helps the environment by breaking down organic materials like leaves and plant debris. (we obviously don’t want mold to do this to the wood that our house is made of) 

So what is this mold issue all about?

Window sills are the most likely to be affected by mold spores among all house’s nooks and crannies. Winter is the most probable time for this to happen. Why? Condensation.

The difference of temperatures between the wintery cold outside and warm places inside the house enhances the process of condensation.  

See, windows separate the outside from the inside, so both sides have different temperatures, making window sills vulnerable to black mold invasion. 

Condensation on the windows adds moisture to the area around the windows, creating damp conditions for the mold to thrive on.

In nature, after condensation, the water vapor or the moisture in the atmosphere takes one of the condensation forms, such as dew, frost, fog, and clouds. In your case, condensation will initiate the growth of surface mold.

That’s why winter is challenging to prevent mold growth and keep the surface clean. 

Even the best cleaning products won’t help if additional damp conditions make for the perfect environment for the “regular” or black mold to appear. 

Tip: You may have an idea to cover up your windows with heavy drapes in the winter to protect yourself from the cold and cover the black mold from your visitors. That’s not the best idea, as the shade favors the growth of black mold spores.

Other silent culprits are these seemingly innocent (and pretty) house plants.

The fungus will soon start growing on your window when it has something to feed on. 

Organic materials, like plants and flowers, are a great source of nutrients for mold.

What’s more, you don’t clean mold so often behind your perfectly set collection of plants. 

If your glass windows at home condense frequently, they become dirty quicker, and fungus development is at its best. 

Also, plants excrete water, which adds to the humidity, encouraging fungus to develop further.

Recognize mold

How to find mold and how to be sure it’s it?

Many of us won’t even notice. 

Yet, it’s dangerous to overlook because windowsill moldy areas can affect our well-being. 

As the mold grows, you’ll also notice that it’s far from decorative for your household’s aesthetics (severe mold damage is irreversible). 

If you see the discoloration is on your windows, it might be mold. 

Only rarely is the mold the same color as the window frame.

Mold usually begins to grow at the bottom of the windows, at the joint between the glass and window sash plastic or wooden frame. 

Window sills are the most susceptible to this issue. So if surface cleaning and keeping your windows fresh and tidy isn’t enough, you may be dealing with fungus. 

While a small amount of mold isn’t dangerous, the real problem begins when it grows through windows, the proper cleaning doesn’t help, and it continues to spread even further. 

Important: Remember that the mold you can see isn’t the total amount of mold your house surface has accumulated. Mold is dangerous for health, but it can also completely destroy the wood or plastic surface of the window frame.

Prevent mold

In the next paragraph, we will discover how to remove black mold, clean mold from the windowsill, and prevent our windows from further devastation, but first, let’s tackle how to prevent mold growth. 

Humidity is a root cause of the appearance of the mold. Damp environments make it grow and thrive. 

So, to prevent mold from growing on your window sills, be sure that the susceptible areas are completely dry, take care of the proper ventilation, and commit to cleaning mold regularly every time it forms on the surface. 

Tip: Remember to wipe off any dampness when it shows up. 

Take care of the air quality, keep the air dry in the apartment (especially in the winter), and keep windows open often to prevent condensation.

Above all else, equip yourself with the right cleaning products and regularly engage in surface cleaning before the problem appears. 

Yet, if proper ventilation and cleaning didn’t help, let’s tackle mold removal below.

Remove mold 

Sometimes it’s too late to prevent mold growth, and we need to act. 

While you’re working on eliminating the root cause, it’s also necessary to get down to the proper cleaning straight away. 

So get yourself rubber gloves and follow one of the great treatment methods that we share below.

Tip: Consider getting professional help, as it makes everything easier and quicker. Call the service near you for a free estimate.

The first, most accessible, and gentle technique is using warm water.

First, damp the area and remove excess mold with a disposable cloth and warm water. Use hot soapy water for the best effect. 

Then, wipe around the pane and frames of the window. 

Important: Prevent mold from getting into the wood frames. Surface cleaning is the best approach in this case. 

Clean rag by rinsing it in clean, warm water after every wipe. 

 Another handy method to kill black mold is a bleach mixture.

Before you begin, remember to put on:

  • safety goggles, 
  • gloves, and a 
  • dust mask;

Important: Get the safety part covered to ensure you kill mold without getting close to it physically. Of all threats, ingesting the dangerous spores released into the air with dust is the most dangerous.

Here’s how to eliminate mold with the bleach mixture in steps:

1. Cover the floor under the windows you’re cleaning. We want to catch any falling mold spores instead of letting them spread and influence the air quality or parquet’s cleanliness. 

2. Provide good ventilation and keep windows open in the room. 

3. Keep goggles, gloves, and a dust mask at hand for your safety. 

4. Prepare a bleach mixture of one part bleach to three parts warm water. 

5. To remove mold from the porous surface. Scrub the mold off of the windowsill using a non-abrasive brush. Dip it in your solution frequently. 

6. In the end, wipe away the window sill with a clean, dry cloth. 

7. Before you close the windows, allow window sills to dry completely. Wipe off any remaining residue or moisture.

Important: You can use bleach to eliminate mold, but remember that prolonged exposure to its fumes can also irritate your lungs, skin, and eyes.

Now you can ‌spray windows with bleach to take care of the fungus invisible to the eye. 

Put on safety goggles once again. Mix a quarter to a half cup of bleach in a gallon of water. 

Use a clean damp microfiber cloth to scrub the window casing.

Let the bleach sit for 20 minutes. 

This step will disinfect and kill black mold that isn’t visible. 

Rinse the window with clean water and make it dry completely. You can even use your hairdryer.

Tip: Don’t forget to address the moisture problem in your house. If you follow steps to get rid of the mold without targeting the moisture issue, it will grow quickly, and you’ll have to repeat the process.

White vinegar is another method to deal with fungus issues around the window frames and sills.

Removing mold with vinegar? Here we go!

First, keep your windows open to help ventilate the room. Vinegar has a strong odor.  

Put on your protective mask, safety goggles, and rubber gloves.

Pour the undiluted vinegar into a spray bottle and sprinkle it directly onto the moldy surface.

Let it sit on a windowsill for an hour or so.

Use a soft brush to scrub the moldy surface until the mold comes off. Then dry completely the area.

Important: While removing mold from non-porous surfaces, use only one of the solutions above. Don’t mix vinegar with bleach or hydrogen peroxide, as it will create toxic chlorine gas! In addition, these acids might irritate your skin or eyes.

Looking for other ways to prevent or remove mold growing in your house?

Get familiar with baking soda, another popular method. 

Baking soda is renowned for its cleaning properties.

To kill the existing mold infestation and prevent future mold growth, reach out for baking soda. 

First, add water into a spray bottle until it’s 90 percent full. 

Now, add half a teaspoon of baking soda and shake the bottle. You want to create a consistent mixture.

Now you can spray the solution on the porous surface and later scrub with a bristle brush. 

Finally, rinse the surface with clean water and let it air-dry. 

Repeat the above steps (spray, scrub, and rinse) until all the mold is gone.

You can also use a half-and-half combination of baking soda and water.

You will create a thick paste (cleansing paste) to apply with a scrub or a sponge. 

Scrub the porous surface, rinse, and air-dry.

Other popular techniques are 

  • tea tree oil (take one cup of water and add one teaspoon of tea tree oil and spray it all over the mold-infested surfaces)
  • anti-fungal product, 
  • hydrogen peroxide, which you can use similarly to bleach, and
  • mix ammonia solution;

Related articles

Frequently Asked Questions

White vinegar is a mild acid that kills mold, roughly 82 percent of its various species. It's also said to ‌prevent mold outbreaks in the future after you treat mold in the affected area with this solution.
Start by taking care of any repairs, such as broken window glass, to prevent leakage. Before you treat mold, ensure there's no moisture around the windows. If you run a humidifier at home, limit moisture spread in the air. Reduce the number of plants and increase ventilation by instilling exhaust fans. Open windows often and draw back curtains to facilitate fresh air flow. All these efforts will lead to keeping mold on window sills at bay.
Leave a Comment