Mold on Window Sills: How to Get Rid of It In 10 Easy Steps Right Now

By: Diana Rodriguez-Zaba
Updated on: March 20, 2024

It’s a headache, but it’s not unusual to find the stuff growing under a sink. You don’t spot mold on window sills nearly as often, but airborne spores can take hold on almost any surface.

Do you know how to get rid of black mold around windows and keep it from coming back?

Sills often breed this type of dangerous mold because affected areas go unnoticed. By the time you see any type of mold on a window’s framing, it may have spread to the apron, sashes and jambs. We see it so often when we take care of mold remediation here in Chicago.

How to Remove Mold From Window Sills: A 10-Step Guide

mold window sills

Split caulking, cracked panes and even leaky gutters allow dampness to creep into sills and frames. Once mold begins to grow, it penetrates wood and affects surrounding materials. These 10 steps can save the hassle and expense of window frame replacements. Try to schedule the job for a day that’s cool and dry.

1. Grab Your Safety Gear

Before getting started, suit up in safety gear. You’ll need goggles, gloves and a dust mask. If you’re taking on a big project, wear an OSHA-rated respirator to protect yourself from airborne mold spores.

Can mold on window sills make you sick? Yes. Mold aggravates allergies, complicates respiratory problems and poses health risks for individuals with compromised immune systems.

2. Inspect the Entire Window

Take a good look at the entire casing inside and out. Look for mold in window seals, on sashes and under hardware. If you miss a spot, you’ll have to do the job over again in just a few weeks.

3. Cover the Floor and Furniture

Cover areas under and near the window with plastic taped in place. This keeps mold spores and debris from settling into the carpet or flooring. Drape plastic over any furniture in the room too.

Power Tip: Minimize spreading mold spores while you work by keeping the HVAC system turned off.

4. Open the Window

You need to open the window to access the entire sill and casing, so try to take care of the project on a cool, dry day. If the weather’s not on your side or it’s too breezy, consider postponing the work.

5. Start With a Hand Vac

Go over moldy areas with a hand vac fitted with HEPA filters. This initial cleaning picks up spores and makes it easier to scrub surfaces. If parts of the window are damp, skip this step.

6. Scrub From Top to Bottom

Often, sashes are affected, so start at the top and work down. Using a mixture of bleach and warm water, scour moldy window frames and sills with a stiff nylon brush. Use old rags to mop up as you scrub away mold.

Power Tip: Keep an extra bucket of cleaning solution handy, and use it to rinse your brush as you work.

7. Wipe Down and Dry

Finish by wiping down surfaces with a clean, damp cloth. Plan on leaving the window open for several hours. It’s important to let everything dry completely. Otherwise, leftover moisture can result in new mold growth.

8. Sand Away Stains

Most mold stains can be removed from unpainted sills with sandpaper. If you’re dealing with painted wood, be prepared to sand, prime and repaint the windows.

9. Hand Vac One Last Time

Go over all interior and exterior window surfaces one final time with the hand vac. Vacuum around panes, inside tracks and jambs and along upper and lower sashes.

Power Tip: When you’re done, disinfect the vac nozzle by wiping it down with vinegar.

10. Roll, Fold and Throw Away Plastic

Starting with the furniture, carefully remove your plastic covers. Roll and fold the sheets inward as you work. Secure everything tightly in strong garbage bags, and move outside for safe disposal.

Tips for Preventing Mold on Window Sills

Cleaning mold off window sills can turn into a big project. It’s not a job you want to do twice, so follow these tips for keeping frames and sills mold-free.

  • Protect wood by wiping away condensation on panes.
  • Keep window caulking and weather stripping in good shape.
  • Clean sills regularly, and check for any signs of mold.
  • Pay extra attention to windows in damp rooms like the bath and laundry.

Always Be Careful

If you’re like us, you love opening the windows on a beautiful day. Still, mold on the sills puts a damper on the freshest breeze. If you’re faced with a cleanup project, follow our guidelines, and always be careful. Don’t ever take on a job you’re not sure about.

Our certified mold removal services cover windows, floors, walls, ceilings and basements too. We’re Chicago’s most trusted mold remediation specialists, so just give us a call. Here at ServiceMaster Restoration by Zaba, we’re always ready to take care of the heavy work.