Q: I have two windows that had a black substance on them. I treated them with a water/bleach mixture, then sanded, re-stained and revarnished. A year later, both windows have more mold on them. How do I find a reputable company to test and clean this for me?
A: First of all, not all black mold is highly toxic, and it’s unlikely the mold around your windows is. Unless someone in your household is sensitive to mold, professional remediation might not be required.
Second, I urge you to investigate why mold is growing on those windows in the first place. Most likely the windows aren’t sealed properly, causing condensation to form on the glass in winter. Water from the condensation can promote growth of mold on the wood.
It’s also possible your house isn’t ventilated well enough or the humidity is too high. But if either of those were the case, you’d probably have problems with all your windows, not just two of them.
Before you call in a mold expert, I urge you to have an energy audit done on the house to pinpoint air leaks and other energy-wasting issues.