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Even though I sealed the interior wood parts of my Andersen double hungs, they still develop black mold or mildew (or is this dead wood?). Please tell me how to remove the black portion and prevent the problem.
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Even though I sealed the interior wood parts of my Andersen double hungs, they still develop black mold or mildew (or is this dead wood?). Please tell me how to remove the black portion and prevent the problem.
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First question: Where are you? In cold climates this is common, too high relative humidity or edge leakage causing condensation on the windows. If this is primarily in the bottom corners of the windows and you are in a cold climate this would be my first guess.
Try cleaning with a fungicide, check with your window guy unless you want to refinish the windows. If refinish then a Chlorox solution works fine. To prevent keep the condensation off the window frames by better ventilation, adding a storm window to move the condensation point or by lowering the relative humidity in the house if it doesn't interfere with health and comfort.