Last Updated: February 27, 2024
Mold and mildew are fungus brother’s microorganisms that thrive in moist environments and homes where sunlight is either poor or non-existent. Like, two siblings with similar features, mold and mildew survive on porous, organic materials and spread swiftly on various surfaces, including crawl spaces, house siding, bathroom walls, wood, insulation, upholstery, clothing.
Both mold and mildew thrive in moist, warm areas where they might sprout their homes. They can also grow on many surfaces, from food to your shower to a sheet of paper. While mold and mildew are often talked about in the same breath, they also have striking differences in size, color, texture, and growth and must be treated differently.
What is Mold?
Molds are microscopic fungi that contain multiple identical nuclei. They grow in the form of patches, and attach to materials with tiny filaments, and penetrate beneath the surface. Mold spores can survive extreme conditions and spread swiftly to affect large areas.
More than 100,000 species of mold exist and are found everywhere in nature and help decompose organic materials like dead trees and fallen leaves. This process allows the nutrients in these decomposed materials released into the soil, becoming available for living organisms to use. While important to nature, molds can be harmful when they grow indoors. Molds can cause health problems and may also lead to structural and cosmetic damages to the buildings. Mold is insidious and burrows underneath the surface, making it difficult to eliminate. When mold spores reproduce and form clusters, then only it becomes visible to the human eye.
Mold grows in warm, damp, and humid conditions and can survive any organic surface where moisture and oxygen are present, including wood, leather, clothing, paper, furniture, etc. It also grows in places where water is collected and not cleaned regularly, such as leaks in roofs and windows or behind appliances. You can identify mold in irregular green, black, brown, orange, pink patches. It often appears fuzzy and is typically accompanied by a pungent smell as it produces microbial volatile organic compounds (MVOCs) when it grows.
Mold can lead to minor to serious health issues, depending on the type of mold, length of exposure, and pre-existing ailments. Prolonged mold exposure can affect the nervous system, resulting in headaches, mood changes, respiratory illness, and can also cause skin and eye irritation, congestion, and general aches and pains. If the person has a mold allergy and asthma, mold exposure may cause coughing, wheezing, chest tightness, shortness of breath.
Common Mold Types
Most household molds belong to one of the following five groups.
Alternaria: This mold is found in damp places, including walls, showers, windows, sinks, etc. Alternaria generally appears black, grey, or dark brown and has a wooly or down-like texture. Prolonged exposure to Alternaria can trigger allergic reactions and asthma attacks.
Aspergillus: This is the most common mold found indoors and usually grows on walls, insulation, paper products, and clothing. Aspergillus mold appears grey, brown, yellow, green, white, or black. Exposure to this mold can lead to allergic reactions and respiratory infections, and lung inflammation in people with weak immune systems,
Cladosporium: This mold grows in cool areas and develops on fabrics like carpets, curtains, wooden surfaces, cabinets, and floorboards. Cladosporium comes in black or olive-green color and can provoke a variety of respiratory ailments.
Penicillium: It is found on surfaces that have been contacted with water, including carpeting, wallpaper, insulation, and mattresses. Penicillium appears blue or green and produces strong, musty odors, and has a velvety texture. This allergenic mold’s spores spread swiftly and can trigger allergic reactions.
Stachybotrys chartarum: Also known as “black mold,” it is one of the most dangerous types of household mold. Stachybotrys chartarum generates toxic compounds called mycotoxins that can cause severe health problems, including respiratory issues, asthma attacks, chronic sinus infections, fatigue. The black mold generates a musty odor and usually grows in regularly damp areas – leaky pipes, air conditioning ducts, etc.
What is Mildew?
Mildew refers to a surface fungus that can be identified as a patch of gray or white fungus lying on a moist surface. As per FEMA, mildew can be described as an early-stage fungus. Unlike mold, mildew doesn’t penetrate surfaces and grows on top of flat surfaces.
Mildew’s health effects are not as severe as mold; breathing in mildew can lead to allergic-like reactions and cause coughing, headache, sore throat, and respiratory problems. It is also hazardous when consumed since mildew can grow on specific plants and crops.
Common Mildew Types
Basidiospores: This type of mildew is associated with dry rotted wood. Basidiospores eventually become mushrooms and can cause severe allergic reactions.
Aureobasidium: Also known as “bathroom mold,” this mildew is found in showers and bathtubs.
Botrytis: This type of mildew is found on indoor plants and can trigger asthma symptoms.
How Mold and Mildew Form
Mold and mildew are found indoors and outdoors and can enter your house through doorways, windows, vents, and heating and air conditioning systems. Mold can also attach to clothing, shoes, and pets and be carried indoors.
When mold spores drop on a surface with excessive moisture, such as roofs, pipes, walls, plant pots, or areas with flooding, and germinate and grow. They start growing as early as 24 to 48 hours on a damp surface. Mildew’s white-gray spots spread outward, remaining on the surface. On the other hand, mold eats into its base and sometimes grows upward.
How to Identify Mold and Mildew
If you are unsure what type of fungi you are dealing with, get them tested to identify and plan for removal accordingly.
Mildew is easier to identify through the site by its powdery appearance and white or gray color. Molds are more difficult to detect as they grow inward or on permanent substances.
An easy way to identify if you are dealing with mold and mildew is to speck few drops of bleach on the affected area. Inspect the spot after five minutes. If the area becomes lighter, it is a sign of mildew, but it is probably a sign of mold in your home if it remains dark.
You can also purchase an at-home test kit to determine the presence of mold in the house. These kits are available in stores and also online. The test kit uses Petri dishes to capture mold scores. Once this dish has been exposed to the house air for several days, it is sent back to the manufacturer to confirm whether or not mold is present in the house. While home-testing kits are suitable for preliminary screening, they won’t help you locate the mold’s source.
Professional testing – if mold growth has gone out of hand and you are not sure how to tackle them, look for professional assistance. They use advanced testing methods, including air sampling to test the concentration of spores in the air; surface testing that collects samples through swabbing or tape lifting; and bulk testing that involves collecting materials from different places in your home. Bulk testing helps you to mark the areas with the highest concentrations.
Effects of Mold and Mildew
It is difficult to identify mold and mildew spores with the naked eye until they have made a colony of spores. In small settlements, neither mildew nor mold is a severe problem when taken care of quickly.
As mold generally grows inside the soil, it often goes unnoticed in unused areas such as the basement and spreads into other rooms. If left unattended, it can result in considerable structural damage. When trapped underneath the flooring, mold can escape into the house and ruin furniture, carpets and other areas once the foundation is exposed. Homes with severe infestations may require the replacement of walls or entire roofs.
In 2004, the Institute of Medicine (IOM) found sufficient evidence of mold exposure leading to upper respiratory tract symptoms, cough, and wheezing in healthy people. Newborns, elderly, and people with weak immune systems can be severely affected by mold exposure. Toddlers love to crawl around and may get touched on moldy surfaces and may stick possibly moldy things in their mouths, which may lead to mold-induced illnesses. Recent studies found a potential link of early mold exposure to the development of asthma in some children.
How to Treat Mold and Mildew
Mold is only visible when the colonies start growing despite its smell. Hence, early detection and prevention are complicated, and DIY remedies are rarely efficient as the fungus grows in difficult-to-reach areas. If you find mold in the house in small concentrations on easy-to-clean surfaces, you can use cleaning or bleach to remove the mold. However, as per EPA, if you find mold spores growing on studs, subflooring, HVAC systems, or drywall in an area exceeding nine square feet, hiring a professional mold removal service is ideal. Improperly treating severe infestations can cause cross-contamination to other areas.
You can clean mildew with a commercially available cleaner, a mild detergent with water, a combination of vinegar and water, or a bleach solution of no more than 8 ounces of bleach in 1 gallon of water. Avoid mixing bleach with ammonia or other household cleaners as it produces hazardous fumes.
Wear a good quality respirator to prevent inhaling mildew spores and avoid breathing in fumes given off by the cleaning product. Use non-porous gloves and eye protection if you’re scraping.
Dispose of unwanted infected material, such as wallpaper, rotted drywall, wood, and fabrics. For mildew or dry mold, spray around the infected area with clean water to prevent the spores from spreading into the air. Then spray the infected area with lukewarm soapy water or vinegar-water solution and rub with a sponge or brush. Frequently change the water and use a fresh sponge. Allow the solution to dry for 10 minutes and repeat the process at least twice to remove all fungi. Let the area dry completely for at least 48 hours before you can put it back in service.
When cleaning certain fabrics or furniture for mold or mildew, take them outside to prevent the spreading of spores in the house. Treat the material or upholstered pieces individually. If the fabric is wet, let it sit in the sun until dry and remove as much mold and mildew as possible with a brush. For remaining stains, use bleach or a cleaning solution. Run the material in the machine if it is washer-friendly. Some fabrics are sensitive to chlorine bleach, soak them in oxygen bleach and hot water for a half-hour, then wash with a hand or machine.
If you cannot take the upholstery outside, vacuum it and dispose of the dirt outside. Sponge or dab with a clean cloth the affected area with a cleaning solution. Dab until the material absorbs the liquid and repeat the process until the stain disappears. Sponge the area with cold water to remove the cleaning solution.
Cost and Time of Mold Removal
The cost of mold removal will depend on the severity of the infestation, the location of the infection, and the type of material it is growing. Generally, mold remediation costs between $500 and $4,000 and takes one to five days, but severe cases of toxic mold can take weeks or months.
How to Dispose of Moldy Material
If the infected fabric, upholstery, carpet, or furniture is beyond cleaning and drying, dispose of them or call a professional cleaning service. Do not try to DIY highly infected materials. One square foot of moldy drywall may contain more than 300 million mold spores, and not handling damaged materials carefully will stir up spores and spread them around the house, and air, where you’ll inhale them. Even dormant spores inhabiting dried-out materials find moist environs again; they can spring back to life and establish new colonies.
Lightly spray water and hand-dishwashing solution in insulation, carpet, and other materials before disposing of. Ensure to move slowly and carefully not to disturb the spores. Double-bag or double-wrap all the discarded material. Scrub the remaining hard surfaces with a 1/2 percent household bleach solution.
How to Prevent Mold and Mildew
While you have thoroughly cleaned the infected area, you are still at risk for mold and mildew deposits. Scrub, dispose of, and replace moldy materials all you can, but mold will return until you fix the problem. Take preventative measures by eliminating moisture and maintain a good standard of housekeeping to prevent future infestations.
Stagnant air traps humidity and creates the perfect environment for mold and mildew to grow. Keep the ventilation in your home by opening windows and using fans. Use exhaust fans that vent outside your kitchen and bathroom. Ensure to have the clothes dryer vents outside your home.
Clean windows regularly to prevent moisture, dust, and debris from collecting. It would help if you also considered deep cleaning your entire home at least twice a year.
If you have leaky air conditioning duct joints, seal them with a sealant, especially in the attic. Change your HVAC filters and HEPA filters regularly to prevent growing mold and mildew.
Moist soil and leaves are an ideal breeding ground for mold. Remove any mildew-affected plants at the earliest once you see the sign of infection. Add Taheebo tea to the water spray on indoor plants.
Use air purifiers to remove mold spores from the air and prevent them from forming clusters and growing.
Keep humidity levels between 40%-50%. Can dehumidifiers help? An air conditioner or dehumidifier will help you prevent mold formation by keeping the moisture level within the range.
Bathrooms contain a lot of moisture. Ensure that it remains well-ventilated. Use an exhaust fan to circulate the air and remove moisture quickly. Spread towels out after use to ensure that they dry out quickly. Wipe down the shower with a clean towel or after daily use. Use easy-to-dry shower curtains to help avoid soap residue, which fosters mold. Leave your washing machine open between uses so it can air out.
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