A moist atmosphere is ideal for the growth of mold. Even though high-quality windows do a good job of keeping out moisture, condensation on their sills is possible. Mold can grow on window replacement casings if left untreated.

Before you panic, have a look at these helpful ideas on how to identify the mold, get rid of it and prevent mold growth from happening in the future.
How Do I Tell If My Windows Have Mold?
Mold usually starts growing near the bottom of windows, where the glass meets the sash frame. Sometimes the mold is the same color as the window frame, which makes it difficult to detect. Tiny stains on windows are unsightly but harmless. Most homeowners are unaware that the mold they see is not the complete amount. Mold in large quantities can be harmful to your health and that of your family. In most cases, window mold doesn’t eat the glass, but it can eat the wood
Getting Rid of Molds
- Always put on safety goggles, gloves and a dust mask before you start. You want to avoid inhaling the mold’s harmful spores.
- Cover the floor under the window you’re cleaning to catch any falling mold.
- It is also critical that the room be properly ventilated. Open double hung windows or doors to let mold spores out instead of locking them in.
- Mix one part bleach to three parts warm water. Scrub the mold off the windowsill using a non-abrasive brush dipped in the bleach mixture. Remove the mold using a clean rag.
- Allow the windowsill to dry completely before closing the window. Remove any leftover residue.
Preventing Mold Growth on Windows
- Use Bleach to Clean Windowsills
Clean your windowsills with a 3:1 solution of soapy water and bleach on a regular basis. Cleaning assists in the removal of debris and mold spores, while bleach kills mold and other organisms.
- Improve Window Air Flow
On dry days, consider opening your gliding windows a few inches. Open the drapes and any blinds. If you have central air conditioning, turn on the fan to circulate air throughout the house and prevent mold growth.
- Consider a Dehumidifier
A dehumidifier can help dry out rooms after carpet cleaning, a leak or humid days.
When it’s time for window replacement, turn to Renewal by Andersen® of Seattle! Give us a call at (206) 970-8976 or fill out our contact form to schedule a free consultation. We work with residents in Bellevue and the surrounding areas.