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What Does Mold Look Like on Drywall? 7 Signs to Watch Out For

molds on the wall

Your health and well-being are threatened if pests, fungi, or bacteria contaminate your home. It’s advisable to seek and look for these contaminants’ signs actively. There are a lot of areas inside your house where moisture attracts mold growth, and dark spots on your drywall are a clear indication of an infestation.

There’s no telling where mold will appear but keeping your house well aerated and promptly dealing with moisture and leaks helps. Drywall may be fire resistant, but it’s prone to wetness, and it’s essential that you accurately locate and diagnose this fungal menace.

Mold has a very efficient reproductive system, which ensures its microscopic and airborne spores are everywhere. To keep your family healthy, you shouldn’t allow the fungi to take root in your drywall. Continue reading to see how to identify mold growth on your drywall, exploring the seven signs to look for.

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What Does Mold Look Like and Why Does It Affect Drywall?

As one of nature’s hardiest organisms, mold is a fungus found everywhere as long as the conditions for growth are right. Recycling organic matter to return nutrients to the soil during the decaying process is essential, but certain strains cause health problems.

The most common mold type is mildew, which grows on the drywall as small dark spots that spread into vast colonies. It grows in damp areas, consuming anything with carbohydrates, including your drywall’s gypsum powder material, and continuously sends spores into the air you breathe.

Mold, especially the black variety, is toxic as it produces mycotoxin, which can cause many allergic reactions and respiratory or neurological damage. Often, an infestation is marked by a fuzzy odor, and you may notice aggravating symptoms like sneezing, runny noses, and headaches when indoors.

Contrary to belief, black isn’t the only color that marks the appearance of mold on your drywall; spots can range from brown to green and other shades. It’s essential to tell the difference between moldy spots and other stains, considering the presence of water and a temperature between 77°F and 86°F.

molds in the wall
Image Credit: D_Townsend, Shutterstock

The 7 Signs That Your Drywall Has a Mold Infestation

Unlike plants that must have light to grow, fungi only require a source of food, the right temperature, oxygen, and moisture to flourish. That’s why your home’s drywall is a prime target for mold since it’s super absorbent when there’s been a water leak within or above the wall.

From afar, mold looks like a vivid watermark on drywall; it gets slimy with a fuzz on top when you get close. Due to uncontrolled leakages or humidity, extensive fungal damage will leave the wall soft and pliable, further affecting its structural integrity.

One way to determine if the dark spots on your drywall are mold or some other substance is with white vinegar or diluted bleach. Dab a few drops on the blackened area; if it lightens after a minute or so, it’s a certain sign that your drywall is mildew. You can also assume it’s the fungi when the spots keep returning even after cleaning.

It’s not easy to control the levels of oxygen or temperature in some unconditioned spaces in your house such as the bathroom, basement, cabinets, and attic. But you can look for signs of mold growth on your drywall as the initial step toward controlling it.

These include:

1. Visible Mold Stains on Drywall

An obvious way to spot molding growing on your drywall is to find dark spotting that passes the vinegar or bleach test. Seeing a lot of visible molding or discoloration means an extensive colony behind the wall, as these few spots are the tip of the fungal iceberg.

Mold prefers damp areas away from light, or where the drywall is exposed to leaking pipes. Other favorite places include ceiling corners, underneath a roof, or near a humid place like the bathroom or water heating unit cabinets. Condensation from a broken air conditioner conduit or an HVAC system malfunction will present mold with dark spotting.

Black Mold in WIndow
Image Credit: Burdun Iliya, Shutterstock

2. A Musty, Putrid Smell

A damp, musty odor that reminds you of old books and paper decay indicates that your drywall is infected with mold. The stench comes from the action of the fungi against the gypsum food source, releasing chemicals called Mold Volatile Organic Compounds or MVOCs.

Mold causes your house to smell like an old house’s basement, wet pets, or cardboard, especially when there’s poor aeration. It’s challenging to identify the type of mold your drywall is infested with by smell alone, but its persistence indicates the fungi’s presence.

3. Lingering Flu-Like Symptoms and Nosebleeds

The culprit could be mold if you constantly suffer flu-like symptoms like sneezing, coughing, dizziness, headaches, watery eyes, and skin irritation. Mycotoxin produced may stimulate allergic reactions, especially in children, and signs of hay fever when you’re in the house come from prolific spores in the air.

The presence of mold on your drywall will have you dealing with increased nosebleeds after taking medication. Symptoms can be severe, especially if your children have pre-existing allergic or respiratory conditions, including asthma. If you’re unsure, leave the house for a few days until the ailments disappear.

Man headache
Image By: Pixabay

4. Peeling Wallpaper or Cracking Paint

Mold on your drywall will affect the decorative covering of your walls, whether wallpapered or painted. A sure sign of moisture within a wall, a precursor to mold, is bubbling beneath the wallpaper or your paint cracking or peeling.

If there’s mold eating your drywall, you’ll find surface deterioration and subtle changes, whether the wall is bare or has decorative elements. A water issue shows stains and discoloration, which may cause bulges, bowing, or warping before or after you’ve seen evidence of mold growth.

5. Spots on Clothing, Leather, and Paper

When you find dark spots on your clothing or leather items, it’s probably an indicator of mold in your drywall. That’s because spores that land on organic fibers and other items often attempt to germinate, leaving splotches that feel slimy and fluffy to the touch.

Spotting mold on drywall is concentrated on clothes, paper, wood, or leather items exposed to moisture. Damp items and the lack of proper ventilation attract microscopic fungal spores, which in turn grow into colonies that contaminate entire areas if left unchecked.

Dirty laundry
Image By: Annie Spratt, Unsplash

6. Deterioration of Air Conditioning Quality

Is your air conditioning or heating system emitting a funky smell when you turn it on, and are there dark fuzzy spots on its filter? Mold on drywall, even when not visibly pronounced, will attack your HVAC and lead to a deterioration of air quality, which in turn breeds more fungi.

A thorough check can reveal moisture leaks within your air conditioning, which alongside temperature, will create an environment that’s mold-friendly. Regular system cleaning and replacing High-Efficiency Particulate, HEPA filters cut off mold’s food sources, dust, and moisture.

7. Stains on Wall Furnishing and Picture Frames

Since mold loves dark and moist areas with no shortage of food and air. Such areas include furnishings within your drywall. Seeing spotting and discoloration on wooden picture frames and watercolor painting canvas indicates your home has a fungal invasion.

Stained wall furnishings happen when leaking pipes or hot air conduits within the wall or when loose flashing boards allow external elements like moisture and humidity. These spots soon turn fuzzy and slimy if left untreated as the fungal colony spreads under the right ecosystem.

spraying molds on the wall
Image By: Dmitriy Utlanov, Shutterstock

How to Tell Whether it’s Mold or Something Else on Your Drywall

While mold is unmistakable, the stain you’re looking at could result from further growth or occurrence that makes the surface appear suspect. You can do several quick tests on your drywall to ascertain the presence of the fungi so that you can take corrective measures.

Besides a mold test kit, which costs approximately $50, you can use a homemade approach that involves dabbing the area with natural white vinegar or one part bleach in 16 of water. If it’s fungi, the spot will lighten or change color after a minute or two as already mentioned in this article.

You can also carry out the screwdriver test to see if you have mold in your drywall or if it’s a water stain that’s yet to get infected by the fungi. Probe the suspect area on your drywall with a sharp implement, and if the gypsum crumbles, the rot may have set in already.

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Air conditioners, exterior walls, and air ducts help to eliminate mold, but it’s still a common invader in houses, especially in moisture-rich areas. The sneaky fungi, which prefer the dark interior crannies of your home, are detrimental to your health and your house’s structural integrity.

To stay safe and healthy, you should regularly check for mold, as it prefers places where you rarely venture. Besides a comprehensive inspection, you can now tell the difference between dirt stains on your drywall and this fungi’s infestation.

Featured Image Credit: epixproductions, Shutterstock


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