How Does Mold Grow?

If you’re a property owner, you’ve likely encountered mold somewhere in your home or business. Mold is often found in bathrooms, around water sources and drains, and in other areas where moisture is present with poor ventilation.

Once it begins growing inside a building, mold can cause damage to the property and trigger potential health problems for the people who live or work there. Because of this, removing mold quickly and properly is important to protect both the structural integrity of the property and the health and safety of occupants.

There are also steps you can–and should–take to help prevent mold from growing in the first place. To do so, it’s helpful to know some common facts about mold, including how it grows, how long it takes to grow, and the environmental factors required for mold to grow. Read on to find the answers to these questions and the steps you can take to help prevent indoor mold growth on your property.

What Does Mold Need to Grow?

Mold requires three key things to grow: moisture, oxygen, and a food source. While moisture is the primary factor needed for mold to grow, certain household items can help “fuel” mold growth once moisture is trapped inside of them. Generally, organic materials–particularly cellulose-based materials such as paper, wood products, and cardboard–are optimal food sources for mold and are most prone to being damaged once mold begins growing. Certain types of paint, wallpaper, carpet, and drywall can also support mold growth.

How Long Does It Take for Mold to Grow?

Mold spores are commonly found indoors, but they are typically dormant until moisture is introduced. Once those mold spores have a constant source of moisture, they can begin to germinate within 24 hours. The spores will then start to colonize within 3-12 days, and mold typically becomes visible within three weeks. Once visible, it will continue to grow and spread as long it has access to moisture.

Where Does Mold Grow?

Mold spores are microscopic and exist everywhere, which means mold can technically grow anywhere, indoors or outdoors. Because they are airborne, there are several ways mold spores can enter and circulate within a property, including blowing in through open doors or windows, moving through vents and air ducts, or being tracked inside by people and pets.

Once settled inside, mold spores require certain environmental conditions to reproduce. Mold thrives in moisture-rich environments, so areas where standing water is present, such as around leaking pipes, potted plants, and drains, are common for mold growth. Similarly, areas with excessive humidity or condensation, like basements and HVAC systems, are also prime environments for mold growth.

At What Humidity Does Mold Grow?

While mold is often found in spaces where standing water or dampness is present, mold can also grow in other areas of a property if the indoor humidity level surpasses a certain point. When the relative humidity (a measure of water vapor in the air) increases, furnishings and building materials can absorb the excess moisture, fostering mold growth.

Generally speaking, if the relative humidity (RH) of an indoor space remains below 60%, there is not usually enough moisture in the air for mold to grow, but ideally, RH should stay between 30-50%. If the relative humidity increases above 70%, especially for extended periods, the excessive water vapor in the air will likely be absorbed by the materials in the space, and mold growth is likely to begin.

A/C units, heaters, ventilation systems (or lack thereof), and the general climate of an area can all affect the indoor humidity of a home or business.

How To Stop Mold From Growing

The best method for preventing mold growth is to limit the amount of moisture throughout the property. Unfortunately, in areas where moisture is naturally generated, such as the kitchen and bathrooms, limiting moisture is often easier said than done. Still, there are certain steps you can take to reduce moisture and humidity levels in your property. These include:

- Fix any leaking pipes
- Ensure all interior drains are clog-free and working properly - Use bathroom and kitchen exhaust fans to remove humidity when bathing or cooking
- Ventilate crawl spaces and other areas where moisture could accumulate
- Turn off humidifiers or space heaters if moisture begins to build up on surfaces
- Regularly clean and empty drip trays on appliances like refrigerators and air conditioners
- Ensure dryer exhaust fans lead outside the property
- Refrain from laying carpet on concrete, especially in humid conditions

Contact BELFOR If Mold Is Growing In Your Home

Safely and effectively removing mold from a structure is a difficult task and one that requires a great level of care and knowledge. Therefore, if you discover mold growing anywhere in your home, it is important to contact the experts at BELFOR right away. Our mold removal and remediation process includes:

- Addressing Moisture Problems
- Isolating Areas of Mold Growth
- Removing Impacted Materials
- Cleaning Away Mold
- Drying

Find your local BELFOR office here or download our Mobile App to find the location nearest to you. Contact us today to stop mold from growing in your home.