How Does Mold Spread? 5 Common Causes [+ Prevention Tips]

Last Updated: February 14, 2024

Mold spreads through air and water. Mold releases spores that use different methods to move from one place to the next. However, mold spread through the air is the most common form of growth in households and businesses.

Mold in a home or business can be dangerous. Once established, mold removal can be difficult and dangerous and should only be attempted by professional mold remediation teams because growing and spreading spores can affect occupants' overall health and safety.

But how does mold spread? Three things are true: Mold needs warmth, moisture, and a food source. These elements enable mold to spread through the air — similar to other fungi — where it attempts to colonize other areas and becomes especially dangerous to occupants.

The spread of mold can quickly become an expensive and exhaustive issue. This guide will help explain how mold spreads and the best way to deal with it safely.

How Mold Spreads

Under the right conditions, mold can grow, reproduce, and spread quickly. As mold spores constantly release from the main colony, they use air currents directed by air ducts to spread throughout a residential or commercial property in as little as 48 hours. These mold spores settle and then rapidly multiply, which allows them to colonize and reproduce in new areas.

Continued colonization increases the chance of interaction with mold and occupants. For the health and safety of all, it’s important to know how quickly and in what conditions mold reproduces and spreads.

1. Moisture

Moisture is incredibly important to mold growth, which is why mold is often found where leaks, flooding, and other types of water damage occur. When fabrics and building materials absorb moisture, the combination creates an ideal environment for mold growth, increasing its potential to spread throughout a property.

The following water damage events can increase the moisture in an area, creating the ideal environment for mold to develop and spread:

• Sewage backup
• Plumbing or roof leaks
• Sump pump failure
• Overflows from sinks or bathtubs
• Leaks from a water heater, dishwasher, or refrigerator
• High humidity
• Flooding

2. Organic Food Sources

Mold needs organic substances like wood, wallpaper, fabric, upholstery, plants, and soil to feed from. Keeping these substances away from moisture and in dry areas can help reduce the growth and spread of mold.

3. Time

Different types of mold need different amounts of time to grow, repopulate, and spread, but many types of mold can begin growing within 24 to 48 hours. Within 72 hours, mold growth can begin spreading throughout an area. While it typically takes around 20 days for mold spores to become visible, plenty of damage can happen in substantially less time.

4. Lack of Air Movement

Poor ventilation combined with moisture is a surefire way to encourage and increase mold growth. Without proper air movement, spaces are more likely to become humid, warm, and moist, which creates an ideal environment for rapid growth. While most mold uses air currents to spread, it’s possible for mold in areas with poor air circulation to move from room to room through water, on pets, or by touch.

5. Temperature

The ideal temperature for most mold growth is between 68 and 86 degrees Fahrenheit, a similar temperature range for ideal indoor comfort. Additionally, extreme hot or cold temperatures won’t kill mold. Instead, spores will go dormant until the space reaches ideal temperatures; then, they will start growing and spreading again.

How Fast Does Mold Spread?

Mold can spread as soon as it begins to grow and can grow within 24 hours of encountering moisture. Where moisture is present, mold is likely soon to follow — within 72 hours, mold can begin spreading, and it can become visible in less than two weeks. During and after colonization, mold will release spores, which can spread the colony to other unaffected areas within hours.

How To Stop Mold From Spreading

To stop mold from spreading, the colony must be destroyed and the source of moisture removed. Professional mold removal and remediation services can help identify moisture sources and remove colonies. In contrast, water damage restoration services can repair damage in homes and businesses that result from a flood, leak, or other causes.

After professional mold remediation, incorporate these preventative measures into regular maintenance routines to prevent future growth:

• Regularly inspect the property for water leaks, damage, and visible mold growth.
• Hire a professional damage repair specialist after any water damage event, big or small.
• Proactively correct mold-friendly environments in homes or commercial properties.

How To Get Rid of Mold Spores

The best way to get rid of mold spores is to prevent them from developing in the first place. However, this isn’t always possible. If mold has already begun to spread, it’s possible to control the situation before the spores spread and colonize new areas with the following steps:

1. Control the moisture. Identify where excess moisture is coming from and remedy the problem. Assess windows, roofs, ceiling tiles, insulation, carpet, drywall, and pipes for leaks and other moisture concerns.
2. Get rid of porous materials with mold growth. Drywall, carpeting, wallpaper, and ceiling tiles are common places for moisture buildup and mold growth. These materials cannot be cleaned thoroughly enough to remove all mold spores. Therefore, they should be removed from the property and disposed of properly.
3. Discard wet and moldy materials. Discard any other materials that can’t be cleaned and completely dried to reduce the risk of mold spores returning, spreading, or reproducing.
4. Professionally clean hard surfaces. Concrete, brick, rock, and other hard surfaces without rot can be cleaned professionally by mold remediation specialists at Rainbow Restoration®.
5. Monitor problem areas. Monitor areas where mold has grown before and monitor moisture levels and mold growth.

Following these steps is an effective way to get rid of mold spores. Air filters and purifiers can also help remove and stop the spread of spores, along with these prevention tips:

• Maintain optimal indoor humidity levels (between 30% and 50%) using an air conditioner or dehumidifier
• Fix leaky roofs, windows, walls, or pipes
• Ventilate shower, laundry, and cooking areas
• Clean air filters
• Install an air purifier
• Professionally clean and maintain HVAC ductwork
• Monitor high-moisture rooms like bathrooms, attics, and basements
• Use steel braided washing machine hoses
• Schedule yearly inspections of the roof, windows, walls, and pipes

What To Do If Mold Appears

If there’s mold in a home or business, there are a series of actions to remove the colony correctly, prevent its return, and protect your property. If the existence of mold is questionable, look for circular-shaped spots that are black, dark green, or dark brown, then follow these steps:

• Follow the smell: Mold produces a musty smell that is often the first indication of a more serious problem. If you sense a musty odor, follow this scent to its source and look for discoloration on walls, pipes, floors, and ceilings. If you see visible signs of mold, avoid any direct contact and seek professional help immediately.
• Inspect the refrigerator and pantry: Identify any additional mold sources in areas where organic food sources are popular. Check for mold growth on food, in or around pantry boxes, and open cans or bottles. Discard these items as soon as they are identified.
• Keep away loved ones: Keep all pets and occupants away from the mold, especially those with asthma, allergies, or weakened immune systems. Remove them from the property until professional restoration is complete, as it’s not safe to live in a house during mold remediation.
• Hire a removal and restoration company: Contact mold remediation professionals immediately to finish the process. Mold can be dangerous to people and property, and removal is difficult to do successfully without proper training. Professional teams have the proper equipment to effectively clean the area, dry out the property, and fully remove the source.

FAQ About How Mold Spreads

Can Mold Grow Without Moisture?

Mold cannot grow without moisture. While mold needs moisture to grow, it can survive for some time without access to it. One of the keys to controlling mold growth is controlling its access to moisture.

Does Mold Spread When You Clean It?

It is possible for mold to spread when you try to clean it. Because spores spread through the air, haphazard or DIY cleaning methods could cause spores to enter the air and float to an unaffected surface or area. Instead of risking spreading mold further, contact the mold remediation professionals at your local Rainbow Restoration for mold cleanup.

Can You Spread Mold By Touching It?

Yes, you can spread mold by touching it. Touching mold can disturb it, which can cause it to release spores into the air. These spores can then use air currents to spread to other areas of a property, effectively moving the colony around the space.

Is Mold Dangerous?

Yes, mold can be dangerous. Depending on the type of mold growing in a property and a person’s allergies and immunity, mold can cause allergic reactions, irritation, infections, and in some cases, serious illness.

Stop the Spread of Mold with Professional Remediation

Answering “How does mold spread?” may bring a second question: What to do if there’s mold on a property? Don’t delay if there are signs of mold and water damage. Any wet, damp, or damaged materials can leave a property vulnerable to mold growth and create an unsafe environment for occupants.

Immediately contact Rainbow Restoration for professional mold removal and remediation. Our residential and commercial mold removal and remediation services safely eliminate mold, stopping its spread and creating a healthier, safer environment for all property occupants. Get started by requesting an appointment online or call (855) 724-6269 for emergency services.

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This article is intended for general informational purposes only and may not be applicable to every situation. You are responsible for determining the proper course of action for your property. Services should be performed by licensed and experienced professionals. Rainbow Restoration is not responsible for any damages that occur as a result of this blog content or your actions. For the most accurate guidance, contact a Rainbow Restoration professional for a custom, on-site assessment.