How long does it take for mold to grow behind drywall?

Author: Nia Moen  |  Last update: Monday, February 2, 2026

A general rule of thumb, according to the EPA and the CDC, is that mold can start to develop on surfaces within 24 to 48 hours of water exposure. However, at this stage the mold spores are not easily visible to the naked eye. It usually takes around 18 to 21 days for the mold spores to colonize and become apparent.

How quickly does mold grow on drywall?

mildew and mold will develop within 24-48 hours of water exposure. Even worse, it will continue to grow until steps are taken to eliminate the source of moisture, and effectively deal with the mold problem. Use the diagram on the facing page to assess the extent of mold in your home.

Should I worry about mold behind drywall?

Mold behind drywall can be dangerous to some people with allergies and breathing issues it can be very dangerous. Not all mold is bad but in homes especially if a leak was present or any moisture bad mold can grow. Lowes and home depot sell mold test kits you can probably order them online as well.

Can black mold grow in 3 days?

Black Mold Growth Rate

If you're wondering, “How long does it take for black mold to grow,” the answer is not long at all. The growth rate of black mold can be rapid, but it still depends on its environment. Generally, however, black mold can grow and form a colony within one or two days.

Do I need to replace drywall that has mold?

Many homeowners attempt to simply repair drywall that is infested with mold, but it should always be fully replaced. If you don't replace every part of your drywall that has experienced mold growth, you're only leaving your home vulnerable to much more damage in the future.

How fast does mold form on wet drywall?

How to get rid of mold behind walls?

How to Remove Mold from Inside Walls
  1. Contain Your Work Area. Before you start work, protect the other areas of your home. ...
  2. Remove the Affected Drywall. ...
  3. Remove the Insulation. ...
  4. Dry Out the Area. ...
  5. Vacuum the Space. ...
  6. Kill the Mold. ...
  7. Contain and Encapsulate the Mold. ...
  8. Close and Rebuild the Wall.

Does homeowners insurance cover mold?

Homeowners insurance doesn't usually cover mold damage or removal unless it's the result of a covered peril. If the mold in your residence was caused by something sudden or accidental, such as a bursting pipe or some other covered incident on your policy, you may be protected.

What are the 10 warning signs of mold toxicity?

Although symptoms can vary, the most common symptoms seen in people exposed to mold indoors include:
  • Nasal and sinus congestion.
  • Eye irritation, such as itchy, red, watery eyes.
  • Wheezing and difficulty breathing.
  • Cough.
  • Throat irritation.
  • Skin irritation, such as a rash.
  • Headache.

Can you just wipe off black mold?

Most experts agree that the first DIY step in dealing with a black mold problem is a simple wash and scrub with dish soap. Damp expert Vaughn advises, 'If you have surface black mold on walls or on surfaces in your kitchen ideas or bathroom ideas, you can clean it off with a soap and water solution.

Will mold always grow on wet drywall?

No mold doesn't always grow after a leak. If the temperature isn't right or if the leak is properly dealt with quickly, there's a chance that mold spores won't be able to take root or grow.

What kills mold on sheetrock?

Bleach & Water

Use two parts water to one part bleach, lightly scrub the area and leave the bleach on for a few minutes (but don't saturate the wall) so it kills the surface molds and penetrates the wall to get the roots. Blot dry with a clean cloth afterward. It works best on hard non-permeable surfaces.

How much does a mold inspection cost?

In his California market, the cost can range from $275 for a simple visit to $2,900 for a complex inspection. For homes under 4,000 square feet, Angi estimates the average cost is generally between $300 and $400, whereas larger homes may see prices between $700 and $1,000.

Will a dehumidifier help with mold?

Mould will easily grow and spread if the right conditions are present. So, dehumidifiers don't kill mould, but they can help to prevent it from growing inside your home by reducing humidity. However, the best way to deal with it is to get rid of its source.

Can you get sick from mold behind drywall?

Extensive mold in the home can become dangerous. The reason is that some species of mold produce mycotoxin, a substance that leads to headaches, problems with breathing, and even damage in the neurological system. Other symptoms may even include an annoying odor, sneezing, or a runny nose.

Does FEMA pay for mold remediation?

If you are a homeowner, you may receive Home Repair funds for clean up, removal, or remediation of disaster-caused mold. To be eligible for this assistance, FEMA must verify that you are unable to live in your home because of the disaster-caused mold damage.

Will mold go away if it dries out?

Whilst it's common belief that dry mould is safe, this is not the case. Mould spores do not multiply without a source of moisture but they will re-activate and start growing once they come into contact with water again.

What kills 100% of mold?

Hydrogen peroxide, commonly used to disinfect wounds, is active against a wide variety of micro-organisms including mold. It acts by releasing oxygen at a rapid rate, which kills mold by oxidizing the surface and breaking down proteins and DNA.

Can a house with mold be saved?

Indoor mold growth can and should be prevented or controlled by controlling moisture indoors. If there is mold growth in your home, you must clean up the mold and fix the water problem. If you clean up the mold, but don't fix the water problem, then, most likely, the mold problem will come back.

Can you paint over black mold?

Expert Tip: If you have mold on your walls , do not paint over it. This will only cause it to grow more underneath the paint. Instead, get rid of the mold before priming and painting. Painting Repaired Drywall Using a primer on repaired drywall is crucial for achieving a smooth, seamless finish.

How long does it take to get sick from mold exposure?

According to the CDC, people usually experience their first symptoms within 2 to 9 hours of their first exposure. On the other hand, some people could go for weeks or months before feeling sick if their exposure is limited enough. This is why it is also important to check damp, dark areas of your home for mold.

How do you detox from mold exposure?

Here's a look at some of the best foods to incorporate into your diet if you're aiming to detox from mold exposure: 1. Antioxidant-Rich Foods: Load up on citrus fruits, berries, nuts, and green leafy vegetables. These provide vitamins C and E, which combat oxidative stress from toxins.

What is the average cost of mold removal from home?

Mold remediation costs $2,365 on average, but it can cost between $375 and $7,000, depending on location, type, and size of infestation. Mold removal often requires replacing or significantly renovating your home's materials, making the costs tricky to calculate.

Can I remove black mold myself?

For a natural solution to getting rid of black mold, combine one part baking soda with five parts distilled white vinegar and five parts water in a spray bottle. Alternatively, you can use a chemical-based mold and mildew remover, all-purpose cleaners, bleach or dish soap.

Who pays for mold remediation?

If there is a covered condition that the homeowner's insurance policy covers that causes mold, then the insurance company will cover mold remediation. Excess water from a natural cause like a roof leaking after a rain storm is usually covered by a homeowners insurance policy.

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