window washer illustration

Cleaning Mold from Window Sills

Cleaning mold from window sills is a messy job that demands attention from homeowners who live in humid climates. Certainly, this is not a task to ignore, as mold affects your and your family’s health. With this in mind, we have suggestions on how to perform this chore in an effective way.


Request a Quote
To get us started, please fill out the below form and we will get back to you shortly!

"*" indicates required fields

Full Address*
Interested In
Contact Preference*
This field is for validation purposes and should be left unchanged.

Why Mold Grows on Window Sills

When you understand why this problem occurs, cleaning mold from window sills becomes easier. That’s because you can put preventative measures into place. Let’s face it—everyone wants to devote as little time as possible to this grimy chore.

Specifically, mold grows in places with excess moisture. Common sources of moisture include:

  • Faulty ventilation or heating systems
  • Leaky pipes
  • Poor airflow and ventilation
  • Broken or clogged leaf gutters
  • High humidity

How to Inhibit Mold Growth

Undoubtedly, homeowners in the Pacific Northwest benefit when they take measures to inhibit mold growth in and around their homes. Here are some steps you can take to discourage its growth:

  • Replace HVAC filters regularly
  • Clean air vents and ducts every season
  • Fix and clean roof gutters
  • Place a dehumidifier in damp rooms
  • Cover all dirt crawl spaces

Once you take these steps to keep your living space as dry as possible, you will spend less time cleaning mold from window sills.

Necessary Supplies for Cleaning Mold from Window Sills

Given these points, it is helpful to gather supplies before cleaning mold from window sills. So long as these materials are close by, you do yourself (and your home) a big service:

Rainier Gutter and Window Cleaning worker placing ladders on work truck

Protective gear—Materials that kill mold are harsh on the skin and respiratory system. Consequently, it’s a good idea to stock up on nitrile gloves, a face mask, and eye goggles before you start this job.

Dry cloths—Microfiber cloths are especially effective in removing mold from surfaces because they are very absorbent. In addition, the small fibers in this cloth help capture mold spores that can’t be seen with the naked eye.

Disposable garbage bags—Have disposable trash bags nearby for soiled rags and materials. Make sure to place these bags into an outside trash receptacle, so mold spores are not released into your home.

A sturdy ladder—Cleaning projects that require you to stand on ladders are frequently dangerous. If you choose to do this job yourself, make sure you use a sturdy ladder to hold your weight.

Cleaning products—Choose cleaning projects that won’t damage your window sills. In particular, wooden window sills can’t withstand harsh chemicals. Therefore, you must pick your cleaning product carefully.

Best Materials for Cleaning Mold from Window Sills

When it comes to messy jobs like mold cleanup, it’s wise to choose the most effective products. The less time and elbow grease you spend on this project, the better. As a result, we have a few suggestions for mixtures that clean mold.

dirty window

Bleach and Ammonia Mold Treatment

Although you can use bleach and ammonia to remove surface mold, this mixture won’t kill it. Therefore, you must clean your window sills every few weeks when you choose this treatment.

Water and White Vinegar Mixture

Unlike bleach and ammonia, white vinegar kills mold because of its high acid level. When cleaning mold from window sills, apply a 50/50 mix of white vinegar and water to the surface. Wait an hour, then wipe the surface clean with a dry cloth.

Cleaning Mold from Window Sills with Borax

Not ideal for delicate surfaces, borax is harsh enough to remove mold from stronger composites. Make sure to wear gloves when you use borax for cleaning mold from window sills. Once you apply it, leave it to dry for an hour. Wipe the area with a clean, dry cloth when it is dry.

Cleaning Mold from Window Sills with Hydrogen Peroxide

Safe for wood surfaces, hydrogen peroxide is a great material to destroy mold. Create a mixture of 50% hydrogen peroxide, 50% water and apply it to a moldy surface. Wait an hour, then wipe away the mold with a cloth.

Tea Tree Oil Mixture to Kill Mold

One of the very best ways to kill mold is with tea tree essential oil. Add 20 drops of tea tree essential oil to a 32-oz spray bottle of water. Swirl the mixture around thoroughly, then apply the mix to the moldy area. Leave the treated area to dry. After an hour, wipe away excess moisture with a microfiber cloth.

Help with Cleaning Mold from Window Sills

Of course, the best way to clean mold from window sills is to leave the job to the professionals. At Rainier Window & Gutter Cleaning, we have the equipment, cleaning materials, and experience necessary to remove dangerous mold safely and effectively. Contact us now to check this essential item off your to-do list.

good scrubbing with gentle brush to remove even mold