Mold Growth in Home: Signs, Risk, and Solution

Look at the walls around you. Do you see moisture or black/green coloration in those walls? It might signify that your home is turning into a mold breeding ground. Another signal of mold growth in the house is a musty or rotten smell. 

Mold belongs to the kingdom of Fungi or Mycota and is a multicellular eukaryotic microorganism. The damp or moist area is the most suitable habitat for mold growth. Mold growth is typical in the regions that have been flooded recently. Also, mold growth is expected inside household settings with moisture from the leaking roof, pipes, and windows.

Mold growth also requires nutrients like carbon, lipids, and proteins. The dust in the construction material like textile, wallpaper, etc., contains plant and animal residue, which can be a nutrition source. According to CDC, Cladosporium, Aspergillus, and Penicillium species are the common mold that grows indoors. 

Areas in the House Affected

Mold Growth in Home
Mold growth in various areas of the home

Molds can grow in paper, cardboard, fabric, paint, textiles, tiles, drywall, dust, and things that are in regular exposure to water and retain moisture. The most commonly affected areas of houses are as follows:

  • Moist walls 
  • Roof after constant raining
  • Air conditioning ducts 
  • Carpets
  • Furniture
  • Water heater
  • Bathroom tiles
  • Kitchen sinks

Signs of Mold Growth

Spores of mold enter indoors with the help of open windows, doorways, vents, and heating and air-conditioning systems. Excessive mold growth shows various signs. The signs are as follows:

  • Smell: A musty or earthy smell can be a big indication of mold growth. Mold produces some chemical compounds during its life cycle, which gives the damp stench similar to old books.  
  • Black or green spots: The mold colony appears green or black. That is why the areas that are affected by mold turn green or black colored. 
  • Regular flare-ups of allergy and asthma: The mycotoxin released by mold triggers different respiratory problems in patients with a history of respiratory conditions. 
  • Bubbling in paint: One of the important signs of mold infestation is bubbling in wall paint.  
  • Distortion of wallpaper: If your wall is covered with wallpaper, it may look distorted or changed. 
  • Discolored tiles: The normal color of bathroom discolors into moldy or black, greenish color. 

Risk of Mold Growth

Mold growth in the houses can carry massive damage to properties; sometimes, one may even need to evacuate their home. The growth also has enormous health risks, especially in immunocompromised people.

Damage to Property

  • Decaying of furniture: The prolonged growth of mold in wooden furniture ruins it beyond repair. Likewise, the growth in metal furniture causes rusting, eventually degrading the furniture and not being suitable for use.
  • Destruction of walls: The mold growth can multiply and spread from affecting a small area to the entire wall. This rapid growth leads to the collapse of the walls, which may need to be replaced entirely. 

Health Risk

People with chronic respiratory conditions like asthma, pulmonary fibrosis, etc., are at risk of severe health issues due to the fungal toxins and spores produced by the growing molds. They may face health issues like:

  • Aspergillosis (fungus ball in the lungs due to prolonged exposure to Aspergillus fumigatus)
  • Difficulty in breathing
  • Allergic reactions
  • Chronic cough
  • Constant headache
  • Skin rashes
  • Memory loss and difficulty in focusing (due to toxins produced by some molds)

Detecting Mold Growth

Detecting mold growth in your home is quite simple. Just look for musky or rotten smells and blackening around the affected areas. But detecting the level of growth is a time-consuming process. A do-it-yourself (DIY) kit is available for detecting mold growth indoors. The kit consists of the following things:

  • A Petri dish
  • A microbial culture media

Materials like painter’s tape and a marker for labeling the sample are required along with the kit.

Procedure for Detecting Mold Growth

The procedure for detecting the mold growth by yourself is as follows:

  1. Close the windows and doors to prevent cross-contamination.
  2. Pour the microbial culture media into the Petri dish and label the lid with the sample name.
  3. Then, leave the Petri dish in the suspected area by opening the lid and the open end facing upward for at least 48 hours (it may vary based on the company used).
  4. Leave the room and seal off the area using painter’s tape for the duration the Petri dish is kept there. 
  5. Close the lid of the Petri dish after 48 hours and label the collection date.
  6. Then, place the Petri dish in a dark area like a dresser, drawer, or closet.
  7. After that, check for mold growth after two days. If there is growth present, it is similar to the growth of mold in food items. If there is no growth after two days, leave the dish in the dark area longer and check every alternative day.

Solution for Removing Mold Growth    

The growth of mold is controllable. The removal process involves cleaning the affected area thoroughly before the growth spreads to another site. Household items are washed with clean water, soap, and detergents. Hard surfaces like tiles and walls are cleaned with bleach. 

Things to Consider While Using Bleach

  1. Mix no more than 1 cup of laundry bleach in a gallon (3.785 liters) of water.  
  2. Use gloves, rubber boots, and goggles while cleaning the surface.
  3. Ventilation in the area of cleaning is crucial.
  4. Follow the company’s manual thoroughly.  

How to Prevent Regrowth of Mold?

According to the environment protection agency’s guide, the following things help prevent mold growth in your home:

  1. Keep the humidity level in your house as low as possible.
  2. Ensure the rooms in your house are well ventilated.
  3. You should constantly clean the walls and roof and repair any leakage.
  4. Use paints that have mold inhibitors.
  5. Clean the flooded room before the 24-hour mark.
  6. Remove infected carpets and furniture.
  7. Clean bathrooms with disinfectant products. 


Ashma Shrestha

Hello, I am Ashma Shrestha. I had recently completed my Masters degree in Medical Microbiology. Passionate about writing and blogging. Key interest in virology and molecular biology.

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