Are Your Walls Covered in Mold or Are They “drywall Ghosts”?
You are a homeowner. One day you notice dark, unclear lines that appear on your walls or ceiling. Your first thought might be mold , and that’s a little scary. But if the lines clearly follow the framing behind the drywall , they are likely evidence of a phenomenon called “halos” or “thermal bridging.” The good news is that, although it is unsightly, ghosting on drywall does not pose a threat to your health, and there are ways to deal with it. But first you need to make sure that it is not mold.
What is ghosting on drywall?
Drywall ghosting occurs when there is insulation between the wood framing, which can result in a temperature difference: drywall covered with insulation remains warmer, while wood framing becomes colder due to the lack of insulation. Then, your daily activities inside your home—showering, cooking, even breathing—produce warm air, which creates condensation on cooler areas of the walls or ceiling. Add dust, airborne dirt or grime from burning candles or other sources, and these damp, cold areas will begin to turn into faint spots called halos.
First, make sure you don’t have a mold problem.
A few things to keep in mind:
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It’s important to note that you should check for mold if you see anything that looks like ghosting – although rare, mold is not out of the question due to it appearing on walls or ceilings in a grid pattern.
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You should also check your insulation: if the insulation in your walls or attic space was installed inconsistently, you may have random cold spots that may develop ghost lines that are not adjacent to the framing grid.
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Another way ghosting can appear is through circular spots above light fixtures: the heat from the light bulbs can rise, find cooler spots on the walls, and combine with soot or dirt to form a ghost stain.
In general, mold tends to be more chaotic in appearance, developing as round patches that do not adhere to the mesh or appear almost like “shadows” of light fixtures. And if the stains on the walls or ceiling are inverted—with dark stains on either side of the frame leaving “clean” lines—it’s most likely mold.
How to Get Rid of Ghost Lines on Drywall
If you rule out the possibility of mold, the good news is that ghosting is purely a cosmetic problem. This does not pose any threat to your health. All you need to do is to properly clean the stains, prime and repaint the walls:
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Scrub the walls with soap and water to remove stains. If the stains are stubborn , you can use a soot removing sponge or a magic eraser sponge.
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Dry the area thoroughly.
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Prime the entire wall or ceiling with a stain-blocking primer to prevent stubborn stains from recurring. Wait until the primer is completely dry and then paint again.
It’s important to note that if you don’t address the root cause of drywall ghosting, it will happen again even after cleaning and painting. This may mean insulating your attic or walls and eliminating sources of soot or other dirt in your home. You can also try lowering the humidity in the room to reduce the sources of moisture that cause condensation.
Drywall ghosting may be alarming at first, but it is fairly harmless. Unless these weak lines turn into messages, in which case you should leave immediately.