How Fast Can Mold Grow

Coming home from a long day at work and all you want to do is take a shower. As you open up your shower curtain and begin to step into your shower you begin to notice some black mold growing on the grout of your shower tiles. Unfortunately, water and humidity are huge breeding ground opportunities for mold spores. How fast can mold grow? Within 24 to 48 hours after water damage. Mold can take hold of your home and grow rapidly within 12 days.

Let’s take a look below at what mold is and how we can prevent it.

What Is Mold

Mold is a naturally occurring organism that represents the fungi family and can grow inside and outside of your home. It consists of spores that are carried around in the air and settle in areas of high moisture and humidity. Oftentimes you notice mold based on the color that it appears as in your home. Mold spores show themselves as black, brown, white, blue, green, orange, or purple.

The color of the mold determines how detrimental the mold is to your health. Black, green and yellow mold is the most harmful mold around you and your home. Mold removal is recommended if any of these mold colors appear in and around your home.

Mold Types

Let’s explore a variety of mold color types and see how what types of surfaces they typically grow on.

  • Black – one of the most harmful molds found in your home. Very toxic to your health as they produce mycotoxins. Should be immediately professionally removed.
  • Blue – most often found in the dampest areas of your home. For example, the ceiling or walls of your bathroom.
  • Green – very much like blue, found in the dampest areas of your home. Typically, shows itself in the dampest corners of your walls.
  • White – this is most commonly found in basements and the cooler more damp environments of your home. Spraying it with water can determine if it is a mold or a mineral deposit. If you spray it and it dissolves it is not a mold.
Mold removal by a professional.
Mold removal by a professional.

How Does It Grow

The most obvious reason for mold to grow and spread is dampness in your home. Often excess water can enter your home via cracks and crevices to your foundation. This allows moisture in the walls of your home to increase and mold to start growing. It can take 24 hours to 48 hours in a moisture-filled environment for mold to grow.

  • Water – the longer you allow standing water in your home, the faster mold can breed in and around your home. The amount of moisture in your home can create the need for mold remediation.
  • Humidity – keeping your home cooler allows you to keep the humidity levels down and the likelihood of mold growth way down.
  • Ventilation – letting the air circulate in and out of your home keeps your home dry and free from mold growth potentials.
  • Organic Surfaces – organic materials such as paint on your walls with inorganic paints reduce the chances of mold feeding.

What Damage Does It Do

The most prevalent impact of mold growth is your health. Sure, it grows on surfaces, and many times we have to replace those surfaces with new materials. However, anyone exposed to mold typically suffers from coughing, wheezing, itchy skin, and itchy eyes, as well as other health-related allergies.

The longer mold is allowed to eat at the surface of your home, the more damage the mold can cause. If you do not treat this mold problem, the structural integrity of that surface can become stressed to a point beyond repair. Damage restoration and water damage cleanup can be costly if not conducted quickly.

How Can I Prevent It

Making sure that your home has a moisture level that is less than 50 percent of the air in your home is vital to preserving the ability to prevent mold from growing in your home. Consider installing a moisture meter in your home. This allows you to keep an eye on the moisture levels in your home and adjust your home’s temperature as needed.

Opening your doors and windows and creating a cross breeze of fresh air can also assist in keeping moisture levels in your home down. The more the air can escape and new air enter, the less humid the air is in your home. Also, maintain the exhaust fans in your bathrooms so that excess moisture from a hot steamy shower is pulled up and out of your exhaust fans’ air vents. Keeping your fans on for up to 20 minutes after a hot shower allows all excess moisture time to be pulled up and out of your bathroom.

Lastly, check your home for any leaking pipes inside your walls. If you notice water pressure reductions in your home, it is a great idea to have the walls scoped for possible leaking pipes. This can be done by thermal imaging devices that identify the moisture levels.

Thermal imaging device for moisture detection.
Thermal imaging device for moisture detection.

How Much Does It Cost

Typical mold removal costs average $20 or more per square foot. A small mold removal project is likely to run you about $600. A large-scale mold removal project costs around $7,335. Keep in mind that the type of mold being removed can have a correlation to the cost you will incur to have it removed. Attic and air ducts mold removal projects have a price tag of $3,000 to $7,000 depending on how much has been affected by black mold spores.

Now that you understand how fast mold grows, it is a good idea to read up on how to stop mold growth in your home. This is the right time to be on the same page when it comes to all mold scenarios.

One of the most common molds is black mold. Oftentimes you will see black mold in your bathroom shower. There are safe ways to clean black mold from the shower. Once you have determined the extent of the black mold in your shower, create a plan for easy and safe cleaning.

Lastly, finding out if mold is in your home is vital if you are looking to buy or sell a home. In most cases, a basic 4-point home inspection can find you this information. One of the parts of the 4-point home inspection involves your plumbing and another involves your roof. Finding any discrepancies in these two areas can give you a great idea as to the potential of mold damage in your home.

Conduct a mold inspection in your home.
Conduct a mold inspection in your home.

When Do I Call A Professional

Calling on a professional is vital to your family’s health and safety when it involves mold. The moment that you or a family member begin to experience health issues due to mold in your home, it’s time for mold removal to occur. In some cases, you will have to relocate your family while the mold is being removed. This is for the safety of you and your family.

Reaching out to your local home inspection team is the most important part here. They can conduct a full home inspection to determine the extent of the mold damage, as well as refer you to the best professional mold removal company in your area.


Keeping your home as dry as possible is the best way to prevent mold growth. All molds thrive on high moisture and damp areas. Typically, we see this in your bathrooms. However, it can occur in other parts of the home, where leaks are possible in the walls. If you have a basement, keep an eye on your basement drain for any clogging. If water pools up in the basement, mold spores will find their way to your basement walls. Once you notice any mold build-up in your home, get it cleaned immediately and call on your local home inspection team. Call on Gray Home Inspections for a mold inspection and complete home inspection in Jacksonville, FL, and surrounding areas.