Does Mold Die When it Dries Out? | MoldBusters (2024)

It is a common belief that dry mold is safe, but is this true? Yes and no. While mold spores won’t multiply without a source of moisture, they will re-activate and start growing once they come into contact with water again.

Not only does mold and mildew damage walls, tiles, carpets and other surfaces around the house, but it is capable of causing a multitude health issues. And although each person responds to mold differently, countless studies show that exposure to mold spores can trigger reactions that range from mildly allergenic to pathogenic and even toxigenic.

So what do you need to know about mold in order to prevent its growth and protect your health? Here is some basic information.

Does Mold Die When it Dries Out? | MoldBusters (1)

What does mold need in order to grow?

The truth is not much is needed for mold spores to grow out of control. Ideal conditions include lots of moisture and food. Indoor mold growth is fueled by moisture. This explains why mold is such a common problem in highly humid and damp areas like bathrooms and basem*nts.

Does Mold Die When it Dries Out? | MoldBusters (2)

In addition to moisture, mold also needs nutrients, which it finds in a variety of materials like paper, wood, drywall or any organic material. More information available in our article about causes of mold growth.

Do mold spores die without moisture?

As mentioned above, the crucial requirement for mold growth is the presence of moisture. Without a constant supply of water, mold will “go to sleep”. However, the spores never actually “die” considering that they can come back to life once more moisture becomes available. Depending on the type of mold, some spores can remain dormant for hundreds of years under the right circ*mstances.

That is why it is not enough to simply eliminate humidity if you have an active mold problem. The mold spores (as well as any contaminated materials) need to be eradicated if you don’t want the mold to grow back. You may consider our mold testing services in Ottawa or Montreal to ensure complete eradication.”

Does Mold Die When it Dries Out? | MoldBusters (3)

Keep in mind that mold can start to develop between 24 and 48 hours of a material getting wet. It will continue growing until it is eliminated (the moisture problem remedied and the mold-contaminated materials removed). If you want to prevent the mold from growing in the first place, ensure that you dry any wet materials within 24 hours.

What happens to mold when it dries out?

Once mold spores dry out, they are temporarily inactive. However, they can still cause uncomfortable symptoms and allergic reactions in humans such as itchy eyes, runny nose, skin rashes and coughing/sneezing.

In addition, dry mold spores are very light and can become airborne quite easily. This can quickly lead to spreading and the contamination of other areas of your home. As such, simply letting mold spores dry out without cleaning or wiping them away is not a good solution to any mold problem.

Depending on the size of the mold contamination, you may either clean the mold yourself (good for small surface mold problems) or contact mold remediation professionals for safe removal of larger mold problems.

At what humidity does mold die?

One way of controlling mold growth is maintaining proper humidity levels in your home. The volume of moisture in one cubic meter of air differs as a function of the air temperature. In other words, warm air absorbs moisture more than cold air. The ideal relative humidity inside your home is anywhere between 30% and 50% if you want to prevent mold.

Using exhaust fans in bathrooms and kitchens where steam tends to accumulate from cooking and showering, improving ventilation, and investing in a dehumidifier are all simple ways of keeping relative humidity low. Open widows frequently to allow for sufficient air exchange, but close them when it rains to avoid moisture intrusion and condensation.

Will mold grow without moisture?

Mold absolutely needs moisture to grow, since its spores use oxygen and warmth to multiply. So the answer is yes; however, different types of mold require different amounts of moisture. In fact, some species of mold require vary little water and can actually survive in the desert. Your best bet to avoid major mold problems is to always dry wet or moist materials and surfaces.

Does Mold Die When it Dries Out? | MoldBusters (4)

Did you know?

87% of homes we tested have mold?! Find out more exciting mold stats and facts inside our mold statistics page.

Are dry mold spores harmful to human health?

People usually think that mold is harmless unless you touch it or eat it. However, because mold spores are microscopic in size, they can be easily inhaled, get trapped in our lungs, and cause a number of health problems.

There have been many studies conducted on the topic of mold and its potential health effects. Various agencies such as U.S. Centers for Disease Control and Prevention, the Institute of Medicine of the U.S. National Academy of Sciences, the World Health Organization and Health Canada agree that exposure to mold at home or at work increase the chances of getting a respiratory disease.

Since some molds produce allergens and others potentially toxic substances, inhaling the spores can cause:

  • Allergic reactions
  • Respiratory problems like asthma and wheezing
  • Irritation of eyes, nose or skin
  • Mental confusion
  • Neurological problems
  • Fatigue
  • Headaches

Once again, it is not enough to kill the mold, but also to remove it totally. Consider getting air quality testing in Ottawa or Montreal to ensure your home’s air is safe.

Should you remove dry mold?

Absolutely! Mold spores are quite ubiquitous, and while some of them can be removed easily during regular house cleaning, many will continue to grow in dark, damp corners of your home or behind walls. Any fungal spore should be removed physically.

Luckily, we have good news – you don’t need to spend a fortune to save your home. All you need to do is call our certified mold removal experts to inspect your property and develop a remediation strategy.

Whether your house has been heavily damaged by flooding or you simply have ongoing humidity problems within your home, there is a solution. Mold Busters services Ottawa and Montreal, helping you to eliminate mold from your home safely and quickly.

Does Mold Die When it Dries Out? | MoldBusters (5)

Call us now for certified mold inspection, mold testing and mold remediation services with same-day appointments available.

With all this being said, the best way of preventing mold is eliminating sources of moisture that fuel its growth. Keep the humidity inside your home within the recommended level and dry any water-damaged materials immediately.

And don’t hesitate to call for help if you discover mold already growing in your home. Remember, mold remediation is not a complicated process if done well!

Resources:

  • United States Environmental Protection Agency, available at: epa.gov
  • Facts About Mold AIHA®, available at: aiha.org
Does Mold Die When it Dries Out? | MoldBusters (6)

Get Special Gift: Industry-Standard Mold Removal Guidelines

Download the industry-standard guidelines that Mold Busters use in their own mold removal services, including news, tips and special offers:

More information

Published: May 19, 2020 Updated: August 3, 2023

Does Mold Die When it Dries Out? | MoldBusters (7)

Written by:
John Ward
Account Executive
Mold Busters

Fact checked by:
Michael Golubev
CEO
Mold Busters

Does Mold Die When it Dries Out? | MoldBusters (8)
Does Mold Die When it Dries Out? | MoldBusters (2024)

FAQs

Does Mold Die When it Dries Out? | MoldBusters? ›

Mold spores are remarkably resilient and can survive in a dormant state for years in dry conditions. Without adequate moisture, mold cannot grow or reproduce, but the spores do not die. Instead, they lie in wait for moisture to return, at which point they can become active again.

Does mold die if it dries out? ›

As you can see, mold does not die when it dries out. Instead, it enters a dormant state and can reactivate once moisture is reintroduced. Therefore, simply drying out mold-infested areas is not enough to eliminate the problem. Mold spores can still pose risks even when they appear inactive.

Does mold actually die? ›

Mold spores won't continue to grow when they are dry. But as we said, they will just become dormant (some even for centuries) and won't die until the right environmental conditions form and cause them to grow back.

What kills mold? ›

Hydrogen peroxide kills mold effectively on materials such as clothing, floors, bathroom fixtures, walls and items such as kitchen appliances. Pour 3% concentration hydrogen peroxide into a spray bottle. Spray the moldy surface completely to saturate the area with hydrogen peroxide.

How long does it take for Mould to dry out? ›

How long does it take for mold spores to die? FACT: Clean and dry any damp or wet building materials and furnishings within 24-48 hours to prevent mold growth. FACT: With water, molds grow. Without water, molds die but the spores do not.

How long does it take for mold to die without moisture? ›

Without a constant supply of water, mold will “go to sleep”. However, the spores never actually “die” considering that they can come back to life once more moisture becomes available. Depending on the type of mold, some spores can remain dormant for hundreds of years under the right circ*mstances.

Has black mold ever killed anyone? ›

While black mold can cause health problems, there isn't definitive evidence to suggest it can directly cause fatality. Melanie Radzicki McManus & Austin Henderson "How Long Does It Take for Black Mold to Kill You?" 1 January 1970.

At what temperature does black mold die? ›

For black mould to be killed off by the heat, the temperature needs to be above 60°C. That's around 140°f, and obviously very, very warm.

At what temperature does mold die? ›

Boiling water can kill mold outright (more on this in the next section), but you can't exactly boil your walls or carpet. However, you may be able to kill mold by heating it enough to dry it out. Most molds can be killed at temperatures of 140 to 160 degrees Fahrenheit, but the effect isn't immediate.

What kills 100% of mold? ›

Yes, bleach is a potent biocide that can be used to kill mold. The active ingredient in bleach, sodium hypochlorite, reacts with water to form hypochlorous acid, which kills mold by denaturing proteins, inactivating enzymes, disrupting nucleic acids, and destroying other cellular components.

How do you make mold go away forever? ›

The only effective way to permanently get rid of mould problems is by reducing the build-up of moisture in your home. This can only be achieved through better ventilation.

What dries out mold? ›

If the relative humidity indoors is maintained below 60 percent, and there are no cold-condensing surfaces, then there will be no enough moisture for mold to grow. However, cutting off any sources of moisture may dry out mold and prevent it from multiplying but they do not die easily.

Can you just wash off mold? ›

Wash your moldy clothes with very hot water and laundry detergent. Hot water will kill mold spores, and laundry detergent will remove any musty smells. Since mold stains are hard to remove, you should also pre-soak your stained garment before washing it.

How long do black mold spores survive? ›

Unfortunately, mold spores can remain airborne indefinitely, especially when mold is present, not fully removed, or disturbed in your home. And even if mold is not currently present in your home, mold spores can travel long distances—attaching to you or pets or entering through ventilation.

How long does it take for mold to dissipate? ›

Homes with large amounts of mold growth will take far longer to complete. Mold remediation is more difficult in homes with high humidity levels and low ventilation. But depending on the size of the home, the severity of the infestation, and moisture sources, remediation should be completed over several days to a week.

Do you have to throw everything away with mold? ›

This is why many toxicologists recommend homeowners treat moldy belongings ASAP. Damaged items should be thrown away without question, and items that are easy to replace or inexpensive (i.e. clothes, food) should be tossed as a precautionary measure. Basically, it's better to be safe than sorry.

Top Articles
Latest Posts
Article information

Author: Gregorio Kreiger

Last Updated:

Views: 6521

Rating: 4.7 / 5 (77 voted)

Reviews: 92% of readers found this page helpful

Author information

Name: Gregorio Kreiger

Birthday: 1994-12-18

Address: 89212 Tracey Ramp, Sunside, MT 08453-0951

Phone: +9014805370218

Job: Customer Designer

Hobby: Mountain biking, Orienteering, Hiking, Sewing, Backpacking, Mushroom hunting, Backpacking

Introduction: My name is Gregorio Kreiger, I am a tender, brainy, enthusiastic, combative, agreeable, gentle, gentle person who loves writing and wants to share my knowledge and understanding with you.