What Causes Drywall Stains?
Drywall panels can become stained for many reasons, and while some of these reasons are simple, others can serve as cause for alarm. If you notice stains on your drywall, you should take time to discover the cause, because the nature of the stain will determine the best course of action for removal. Does this Spark an idea?
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Mold
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Mold loves to grow on drywall because drywall is porous and holds moisture. If you have a leaky roof that causes water to seep into the walls or if you have a leaking pipe behind the wall, the water can penetrate the wallboard. If your wall surface has a large enough accumulation of organic material like dirt or dust, mold can grow on the wall. The type of insulation within the wall can also play a role in your drywall mold risk. Some types of insulation, such as polystyrene insulation, are extremely water resistant, while others, such as cellulose insulation, can absorb water.
Black Soot
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Black soot stains, sometimes called ghost stains, can also penetrate drywall surfaces, often along the outline of the wall framing or near the drywall fasteners. They get the name “ghost stains” because they appear along frames and boards, accentuating the “skeleton,” or inner construction, of the home. Black soot stains emerge when soot particles penetrate the wall panels. Soot can appear with the frequent use of scented candles, gas fireplaces, pilot lights, oil lamps or any device that burns solid fuel or oil.
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Chemical Stains
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Some construction materials can undergo chemical reactions when faced with specific temperatures, air contaminants or humidity levels. For example, mercury-based compounds were once commonly used in construction materials and may still exist in the drywall of some older homes. Hydrogen sulfide (a common contaminant found in the air) reacts with mercury and leaves behind unsightly stains. Stains may appear as a combination of black and gray, and some chemical stains can appear red.
Dealing with Stains
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When approaching a drywall stain, first determine the source. If the stain is wet and has a musty odor, you probably have a mold stain. Dry the wall and clean it with a dilute bleach solution containing 1 part bleach and 16 parts water. Also clean chemical-based stains using dilute bleach. For black soot, reduce your use of gases and oils indoors. Black soot penetrates deeply into wall surfaces, and affected wall panels may require replacement.
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