White Mold in Your Home: Is it Dangerous & How to Remove It!

By thewriteDuffy •  Updated: 09/20/22 •  12 min read

Unfortunately for us, the modern home can create a pretty appealing habitat for a range of molds. 

These molds love warm, moist surfaces and are often found growing in kitchens, bathrooms, basements, and other any wooden surfaces where condensation forms.

If you find something forming on a moist surface in your home that looks white in color, identifying it as mold will be important for your home and your health, so keep reading.

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What is White Mold?

White mold is actually an umbrella term used to describe a variety of molds that commonly grow in the home.  These molds appear white on some surfaces, but on others they can be green, gray or even black in color.

According to the CDC, the most common indoor molds are CladosporiumPenicillium, and Aspergillus. These molds are a type of fungus made up of thousands of tiny threads known as hyphae, which can appear white.  These tube-like threads spread out to create a network known as a mycelium and it’s often only once this network has expanded that we’re able to notice the mold.

In order to survive and grow, white molds need moisture to absorb nutrients from their environment. Once the mold has taken all the nutrition from one spot in your home, it needs to send out more hyphae to obtain nourishment, hence white mold often takes over large patches if it has been left untreated, which is when it can become hazardous.

With that said, there are other substances besides mold that can create large patches of white stuff in your home so let’s first make sure that’s what you’re dealing with.

What Does White Mold Look Like?

White mold looks like patches of white powder, film, or threads growing across a surface.  When in its powdery form, white mold can be tricky to spot on pale surfaces.   White mold can change color as it matures because it turns darker as it starts producing pigmented spores.

White mold tends to grow in imperfect circles, though this won’t always be obvious to the naked eye. You’d be forgiven for mistaking this mold for dust on darker objects like furniture or items of clothing – it really does have a very similar appearance, especially once the mold thickens.  

Perhaps the most common lookalike for white mold is mildew.  Confusingly, mildew is also a fungus and it is white until later in its development.  Mildew will tend to be flatter than white mold and it can turn brown over time.  White mold, especially as it advances, will look much thicker and it can grow to have a thready or even fuzzy appearance, while mildew will retain a thin, powdery appearance.

Efflorescence on Concrete vs. White Mold on Wood
Efflorescence on Concrete (Right) vs. White Mold on Wood (Left)

White Mold Vs. Efflorescence

Whilst a white mold is a fungus, efflorescence is a deposit of salt, laid down when water moves through certain household structures. They’re often confused because both present as a white powder in the home. Though white mold is associated with health issues and damage to a property, efflorescence is not.

The International Association of Certified Home Inspectors explains that efflorescence occurs when salty water moves through a porous material in a building, such as brick, concrete, stucco, or stone.  As the water evaporates away, it leaves this white powdery substance which is, in fact, crystalline salt.  Though an efflorescence itself isn’t inherently damaging to the materials it appears on, it is indicative of a moisture problem (which isn’t ideal!) and there could well be a mold problem later on if the moisture doesn’t subside.

Luckily, there’s a super simple test to differentiate between white mold and efflorescence. Spray the white powder with water and if it’s an efflorescence the powder will dissolve and if it’s a white mold, it will remain.  Where mold is growing, you’ll notice its “spread” across the area but efflorescence will not independently spread once it has appeared.  

If you’re very unsure if it’s mold or efflorescence, you can either have a mold inspection done by a licensed inspector or get a DIY mold test kit and do it yourself. If you want to do it yourself, this well-rated one on Amazon that’s very inexpensive for some peace of mind.

If you see any dark spots developing as well among the efflorescence, it’s best to keep reading because it could be the first sign of black mold.

White Mold Vs. Black Mold

When someone talks about black mold,  they’re usually referring to a particular species of black-colored mold – Stachybotrys chartarum.  Both white mold and black mold are bad for your health, but current research suggests that black mold isn’t as severely toxic as previously thought.  Unfortunately, both molds can also damage your property, so swift removal is necessary.

Black mold is easy to tell apart from white mold due to that distinctive color difference, but do remember that white mold can sometimes start to look black later in its life cycle.  Black mold grows in a more irregular fashion than white mold and it has a very notable musty aroma.   Like white mold, black mold penetrates into the material on which it is growing, and this is why it can be so damaging to structures within a property.

Black molds produce harmful mycotoxins which can irritate the respiratory system, especially in those with an allergy. Mold is a known allergen and though the toxicity of black mold may have been exaggerated by some sources,  it is absolutely true that it can trigger dangerous allergic reactions in those who are susceptible.

Is White Mold Dangerous?

Dangers of White Mold to your Health

White mold is not good for your health and like all other molds, it can be particularly problematic for people with allergies or asthma.  Another worry we should have if we locate white mold in our home is the damage it could be doing to the structures which stabilize our property.

It’s generally agreed that touching, swallowing and breathing in mold and its spores isn’t good for the health, and the CDC says that in some individuals we’ll see symptoms such as sneezing, sore throats and rashes, with more serious issues such as breathing difficulties in those with allergies or a compromised immune system.  It is thought that prolonged exposure increases the health-damaging effects, and unfortunately white mold is harder to spot than its darker fungal relatives.

Dangers of White Mold on Your Home

In terms of damage to your property, white mold uses certain building materials as a food source In terms of damage to your property, white mold uses certain building materials as a food source (notably those that contain cellulose) and the EPA explains that untreated mold infestations can literally eat away at the integrity of materials within your home. 

The worst-case scenario is that the white mold and the high moisture levels that encourage its growth could compromise the integrity of the foundations or structural framework of your home – meaning this tiny home invader can destabilize your property!

What Causes White Mold in A House?

Tiny fungal spores are easily carried into our homes in the air or on our shoes or clothing, and these hardy little spores will happily settle on surfaces and colonize.  White mold can flourish when it has access to warmth and moisture, and unfortunately, the modern home can be both warm and humid! 

Though you can’t remove the food sources loved by white mold within your home, something you can do is reduce the moisture that molds need in order to survive.  It is high levels of moisture caused by the likes of leaks, poor ventilation, and condensation that gives rise to white mold and so as you can see, these are things you can prevent or remedy.

The New York State Department of Health points out that we make a lot of moisture in our homes – from baths, showers, bubbling saucepans, and even from the simple act of breathing!  So what can we do to reduce moisture levels in our home to make it a less hospitable environment for white mold? 

The Department of Health advises countering moisture levels by opening your windows as often as you can (ideally, daily), carrying out property maintenance to locate or prevent leaks,  and turning on the extractor fan in your bathroom and kitchen whenever you’re going to create steam. 

Where Can You Find White Mold in Your House?

White molds need a nutrient source, and within the home, cellulose is a firm favorite.  Cellulose is found in common building materials such as wood, drywall, and even wallpaper, meaning there are plenty of nutrient-dense sources within your property.  If that material is located in a warm, moist spot – even better!

Basements, crawl spaces, and attics are the perfect breeding ground for white molds because these are often damp and hard to ventilate.  Thanks to its rich source of cellulose, white mold loves to grow on wood, including structural timbers and furniture.  Clothing and footwear can also be affected by white mold – especially if they’re being stored in one of these humid locations.

If your crawl space features exposed soil, this organic medium can be perfect for allowing white mold to thrive.  From your crawl space, white mold could creep up your property’s framing, potentially giving it access to other regions of the house, via the floor joists.  Its love for drywall and sheetrock also allows it to accomplish a significant spread across a home, moving its mycelium from panel to panel.

What Happens if You Breathe in White Mold?

If you’re healthy and don’t have allergies, breathing in most types of white mold for short periods shouldn’t have any lasting impact on your health.  If you have an allergy or asthma, breathing in white mold can be outright dangerous.  Inhaling certain white mold spores can also be dangerous for those with a weak immune system.

Individuals with allergies have an immune system that identifies certain substances (allergens) as dangerous, and in response, they launch an attack on it.  The EPA states that mold allergies are common and when an individual with a mold allergy breathes in white mold, especially the spores, they may find their eyes and nose streaming, their chest wheezing and rashes, and dry, scaly skin forming. A severe allergic reaction or the triggering of an asthma attack is when breathing in white mold is at its most dangerous.

If you have a weaker immune system, an existing lung condition, or if you’re very young or very old, the prolonged inhalation of white mold may cause respiratory issues.  A notable white mold-related illness is aspergillosis.  The NHS advises that the inhalation of the mold species Aspergillus causes breathing difficulties and other respiratory symptoms such as coughing and sneezing.  Untreated, this can damage your lungs.

Can I Remove White Mold Myself?

Yes, you can remove mold from your home yourself so long as the mold covers an area of less than 10 square feet, you can remove it yourself – just so long as you’re very careful! It isn’t wise to touch or breathe in mold and therefore to protect your skin and lungs, good ventilation, gloves, safety glasses and an adequate mask (at least an N95) are vital if you plan to remove the mold yourself.

This 10 square feet rule of thumb comes from the EPA who also advises that if you choose to hire a company to do the removal for you, to make sure the contractor has experience cleaning up mold. There are a number of guidelines a mold removal company should follow to remove the mold form you home safely. To learn more, check out the EPA site here.

How to Remove White Mold in Your Home Quickly and Easily

Once you can see white mold with the naked eye, it’s really quite well established in its setting and therefore a wipe down with an anti-mould spray isn’t enough.  Mold hyphae can penetrate into porous materials in your home.  You’ll need to allow your anti-mold solution to sit and permeate, so give yourself plenty of time for the removal process.

To start, generously spray on your chosen anti-mold spray, and you can make your own by diluting one part bleach with three equal parts water. Scrub this solution into the surface and leave it to sit for at least ten minutes before wiping it off with clean water and rags.

Don’t forget that wearing the correct safety equipment is also important when removing mold.

Conclusion

Though the claims about the dangers of white mold may have been exaggerated in the past, it’s clear that we still need to be cautious around it.  Reducing our time spent in its presence and removing small patches quickly (or calling in the professionals to remove larger areas) will make sure that we stay healthy and our home stays safe.  White mold reminds us that home maintenance and good ventilation protocols are well worth the time and effort!

References

A Brief Guide to Mold, Moisture and Your Home. (2016). Environmental Protection Agency (EPA). https://www.epa.gov/mold/brief-guide-mold-moisture-and-your-home#tab-7

Aspergillosis. (2021). National Health Service (NHS). https://www.nhs.uk/conditions/aspergillosis/

Basic Facts about Mold and Dampness. (2020). Centers for Disease Control and Prevention. https://www.cdc.gov/mold/faqs.htm

Borchers, A.T., Chang, C. & Eric Gershwin, M. (2017). Mold and Human Health: a Reality Check. Clinic Rev Allerg Immunol 52, 305–322. https://doi.org/10.1007/s12016-017-8601-z

Gromicko, N & Gromicko B. (2022). Efflorescence for Inspectors. Inter­national Association of Certified Home Inspectors. https://www.nachi.org/efflorescence.htm

Mold. (2021). Centers for Disease Control and Prevention. https://www.cdc.gov/mold/default.htm

Mold Cleanup in Your Home. (2021). Environmental Protection Agency (EPA). https://www.epa.gov/mold/mold-cleanup-your-home

Mold and Your Home: What You Need to Know. (2021). New York State Department of Health. https://www.health.ny.gov/publications/7287/

thewriteDuffy

At home, April is a mom, wife, and DIY darling. Among other home projects, she helped her husband Dan renovate their 1986 bungalow and is currently designing and decorating the 2023 custom home they are building themselves. Professionally, April is a writer, author, and online marketer with 15 years of experience writing for newspapers and magazines, building online authority websites, and publishing books.