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Dealing with a mold problem in your home can be a daunting and scary experience. It is hard to know what to do first in situations that seem overwhelming. However, it is important to tackle a mold issue right away, so that it does not become worse and even more daunting of a problem. So what do you do if you have mold in your crawl space? This article will aim to help you break down the process and guide you in making decisions about your home and mold issues in your crawl space.


How to Tell if You Have Mold in Your Crawl Space

The most obvious way to determine that you have a mold problem is if you can see the mold. Sometimes mold is visibly growing in your crawl space, which lets you know you have a problem, as well as visually gives you an idea of how much mold you have. Mold is not always so noticeable though. Oftentimes it can grow in places hard to see. In these cases mold is sometimes discernible by smell. A distinct musty or unpleasant scent may indicate the mold issue.

If you see or smell mold, then it is a good idea to test and see what kind of mold you are dealing with. It is important to know what type of mold you will have to treat before you go ahead and try to manage the issue, though you want to get rid of any mold growing in your crawl space, regardless of the type. Knowing what kind of mold it is will help you figure out how to safely handle the cleanup process.

Why Do You Have Mold in Your Crawl Space?

If you have mold in your crawl space it is crucial to figure out WHY it is there. Even if you clean the mold, if you haven’t fixed the issue it will likely return. There can be many factors to mold growth, but they all involve water damage… whether that be from a leak, or from flooding, or a humidity issue. Mold thrives on moisture. Find out the cause of the moisture that is feeding your mold.

Ventilation is important for issues involving high humidity levels. In a crawl space with an approved vapor barrier, such as 6-mil plastic, ventilation should be a square foot of ventilation for every 1,500 square feet minimum. This works out to about one 8″ x 16″ vent for every 500 square feet. One vent should be within 3 feet of every corner. (International Residential Code, section R408)

If you have had leaks or flooding in your crawl space you likely have mold, even if you can’t see it. Mold can develop incredibly fast in the right conditions. That’s why any mold issue or water damage should not be ignored. The problem will not go away, it will multiply.

Mold thrives in:

  • Darkness
  • Above-freezing temperatures
  • Moisture
  • Oxygen
  • Time (mold can grow in as little as 24 hours with the right condition)

How to Clean Mold in the Crawl Space


It is important to know the type and size of the mold problem you are dealing with. The EPA considers any mold issue over 10 square feet to be too serious an issue to take care of yourself. In these cases you should contact a professional remediation company to deal with the mold cleanup. If the mold problem is a smaller issue, you may try to do the remediation yourself, though you want to take precautions and do so safely! If your health is poor and you have a weak immune system, I’d suggest you check into professional remediation as well.

After the cause of the mold is fixed (water damage, leak, humidity, etc), the mold will need to be scrubbed, killed, and cleaned off the material that you cannot remove and replace. Any mold on drywall or similar material should be cut out and replaced. There are many types of cleaners that can be effective against mold. You will need to research the best cleaner for the surface you are remediating and take the needed precautions and wear the proper protective masks, eyewear, gloves, and clothing for the job. You also want to ensure that the crawl space is properly dried to prevent the mold from returning.

Mold can be a very scary and serious dilemma, but don’t let the magnitude of the problem cause you to put off taking care of mold in your crawl space. The health of your home is connected with your health, and you certainly wouldn’t want to ignore serious symptoms that will only multiply. Prevention is a huge part of avoiding a mold disaster, so keep up with leaks, moisture, condensation, and any water damage in your home and crawl space. It can save you a huge headache later.

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DryHero Water & Mold December 20, 2019 - 8:15 am

Yes! Great article for anybody with crawlspace. You should periodically be visually inspecting for mold and moisture.

Jim January 15, 2020 - 11:01 pm

This is a great help for homeowners that want to DIY clean their own home and not call for a help. Thanks for sharing this great article you have. Keep posting.

Midwest Mold Removal

Robert Ross February 25, 2020 - 5:16 am

Thank you for sharing! At this stage, the main thing is not to panic and not to take rash steps like self-testing mold or trying to remove it in the DIY style. I recommend contacting local mold testing companies directly. Only they will be able to conduct a professional inspection, find the root cause of the appearance of mold, give the most detailed instructions for its elimination (Mold Remediation Protocol) and help to eliminate the mold.

Robert @ O2 Mold Testing

Angela T Lott May 11, 2020 - 5:50 pm

What’s the best route if you can’t afford $2000 for mold removal, I had the problem fix that was causing the moisture under my crawl space, What should I do next

Chad Rickley August 15, 2020 - 1:35 pm

In the Colorado Springs area we have lots of strong thunderstorms and lots of basements and crawl spaces. Mold is a real problem out here, and there are plenty of disaster recovery and mold remediation companies around for that exact reason. Mold testing is important in these situations, so I suggest contacting a professional that has expertise in that area. Once you’ve gotten details on what you’re dealing with, you can contact removal companies like ours.

Chad, Owner

John Smith October 15, 2020 - 8:03 pm

Thanks for sharing such valuable information!

Kurt Dorsey November 8, 2020 - 6:47 am

Check for water leaks in the foundation walls and crawl space ceiling — make sure there are no cracks that allow water to leak inside the crawl space. Ensure that the gutters and downspouts direct water away from your home’s foundation.


Kurt Dorsey November 8, 2020 - 6:48 am

Check for water leaks in the foundation walls and crawl space ceiling — make sure there are no cracks that allow water to leak inside the crawl space. Ensure that the gutters and downspouts direct water away from your home’s foundation.

Kurt | https://www.o2moldtesting.com/

Mahbuba January 17, 2021 - 7:51 am

A mold or mould is a fungus that grows in the form of multicellular filaments called hyphae. This is very annoying. Click here for details on how to remove it. Mold Removal in Attics

Colleen Crawford February 20, 2021 - 8:02 pm

Good read here, I really liked how you pointed that we should be taking care of our home for our health and if we don’t remove mold in our crawl space it will be a serious dilemma.
Roof Repair Katy


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