How Long Does it Take for Black Mold to Grow?

ATI Restoration

When water damage occurs, be prepared to take action quickly to mediate the damage and prevent black mold. Mold spores are ever-present in the environment, but they take hold fast and rapidly grow when the conditions are right. 

Water leaks, condensation, and flooding commonly cause water damage that leads to mold. Mold favors warm and humid conditions, which is why mold exposure is more prevalent in homes and buildings in Southern states and areas with severe storms.

There are many types of mold. While mildew is a form of mold that presents as powdery and white, toxic black mold spores are greenish-black and more difficult to treat. All mold can affect your immune system, cause allergic reactions, and exacerbate long-term health problems.

How to Get Rid of Black Mold


If treated early, a homeowner can keep mold growth at bay and eliminate spores to prevent the spread. It’s important to protect yourself as you treat the mold, so always wear gloves, goggles, and a N95 respirator mask to reduce health effects. 

Follow these steps to treat mild and moderate mold infestations:

  • Turn off HVAC systems and cover vents, and seal doorways with plastic to prevent mold spread. Mold can grow in air vents, so you will want to prevent new spores from circulating in your system.
  • Use a spray bottle filled with water to dampen visible mold; this helps prevent the spores from becoming airborne as you clean them.
  • Drywall, insulation, and carpeting all hold enough moisture to foster toxic black mold growth, and the materials must be removed during mold remediation. 
  • Depending on the mold severity, remove as much as you can, down to the underlayment on the floor, and to the studs in the walls. 
    • Vacuum debris as you go. To prevent extra air circulation in the room, consider keeping the vacuum itself outdoors, and only maneuver the hose with suction inside the space.
  • Treat visible black mold on wood by spraying it with a solution of two quarts of water mixed with one cup bleach. On concrete, use a solution made of TSP and water according to the manufacturer’s directions. Use a soft brush to help the concentrations saturate the mold. The mold will rub off. Do not rinse the areas after treatment.
  • Once the mold is visibly eliminated, allow the treated areas to dry. You can introduce a dehumidifier and fans to the room at this point to control humidity levels and help with drying the surfaces.
  • The mediation process can take some time, so allow the space to dry for 3–4 days before checking for signs of visible mold or a moldy smell to indicate that more black mold is still growing out of sight.
  • If you can still see mold visible, treat the area again.

If you’ve taken these steps and mold is still present, the infestation may be too severe. The expert team at ATI Restoration will get to the source of the issue and provide mold removal services promptly. 

Contact our team online or by calling (866) 294-2341. Our specialists will provide an audit and make recommendations for mold remediation based on the severity of the outbreak.

Black Mold Growth FAQs

It doesn't take long at all for black mold to find its food source and begin to grow in ideal conditions. In fact, within the first day, spores begin to multiply and affect air quality in a space. Mold problems may not be visible for up to 2 to 3 weeks, but by that point, the growth will be more difficult to mediate, and the air quality will be very unsafe. 

When water damage has occurred, get in touch with your homeowners insurance company and a water damage restoration company like ATI Restoration so you can receive mold removal services before the situation becomes critical.

Black mold begins to form and multiply within 12–24 hours when the conditions are right. If you’ve experienced water damage, be sure to take action immediately to dry and dehumidify the area to prevent spores from taking hold. If you need advice for serious water damage, don’t hesitate to contact the experts at ATI Restoration so the team can help you.

Mold spores exist in all environments, but they’re most likely to cause damage when the temperatures are hot, and specifically when the humidity is high. Regions of the country that experience severe winters are less likely to have year-round mold issues, while homes and businesses on seasonal storm paths are more likely to experience mold from reoccurring flooding.

It can take several weeks to detect the trademark greenish-black spots associated with mold visibly, but you may be able to smell it before it's visible. If you've had water damage or if there are moisture-prone areas in your home, monitor for a musty odor. If the mold is out of sight, you may experience physical symptoms as a result, too, such as headaches or cold symptoms. 

There are long-term consequences to living with black mold, so if you suspect there’s an issue in your home, don’t delay getting a mold inspection from an expert at ATI Restoration.

Based on the severity of the damage, we recommend that homeowners leave a house when mold is present and prevalent. An expert mold mediation company like ATI Restoration will make every effort to provide a safe environment during mold removal and remediation. Still, homeowner health is paramount, and while mold is present, the indoor air quality is compromised.

Two construction workers in hard hats and safety vests look at a building under construction.

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