How to Get Rid of Mold in Your Crawl Space

By: Diana Rodriguez-Zaba
Updated on: December 18, 2023

If you have mold in your crawl space, you’re probably wondering what to do about the musty smell and the possible health concerns.

Don’t worry – ServiceMaster Restoration by Zaba is here to help. We have more than 85 years of combined experience in the restoration industry, and we help Chicago-area customers get rid of mold every day.

In this blog, we’ll discuss how to remove mold from your crawl space, clean the area, and more.

Important Safety Considerations

Mold is highly toxic and can create a variety of health problems, including allergic reactions, asthma attacks, skin rashes, and irritation in the eyes, nose, throat, and lungs. 

With this in mind, follow these safety tips any time you’re removing mold in your home:

  • Wear the proper PPE whenever you’re dealing with mold. Wear goggles or other eye protection, an N95 mask or respirator, a long-sleeved shirt, long pants, waterproof boots, and rubber gloves. 
  • Consider whether mold removal is even a DIY job. Because it requires specialized cleaning products and tools, and since it can be hazardous to your health, we usually recommend hiring a professional to get rid of mold in your crawl space. If the mold infestation is extensive, it is recommended to seek professional help rather than attempting a do-it-yourself solution.

In addition to protecting you from mold exposure, calling in the pros ensures total mold removal and lessens the risk of additional mold problems in the future. 

How to Kill Mold in Crawl Spaces: 5 Important Steps

crawl space mold remediation services

1. Assess the Situation

Wearing your protective gear, assess the extent of mold in the crawl space. Set up lights, and lay down plastic sheets to catch mold as it’s cleaned from surfaces. If the job seems too big, contact a mold remediation company right away.

2. Clean the Moldy Areas

Clean affected areas with detergent and water, as recommended by FEMA, or use vinegar, baking soda, or borax to clean the affected area. 

Here’s a quick breakdown of how to use each:

  • Vinegar. Mix white vinegar and water in a 1:1 ratio in a spray bottle. Spray the mixture over the affected areas of the crawl space. Let it sit for a few minutes, and then scrub it according to the directions in Step 4. 
  • Baking soda. Baking soda is a popular homemade mold-removal solution since it can be used on a variety of surfaces. To get rid of mold in your crawl space, spread baking soda onto the affected surface and let it sit overnight. In the morning, scrub it with hot water. This will remove dead mold and any dirt or debris that was stuck to it.
  • Borax. Borax gets rid of mold without leaving any residue behind. To kill mold with borax, apply it to the affected area and allow it to sit – no need to rinse it off. Be careful to avoid contact with your skin and eyes, and always wear PPE when you apply borax. 

3. Scrub Off Residue

Let affected areas dry, and then use a stiff bristle brush to scrub away any remaining mold. This can be a time-consuming process, but you want to remove as much mold residue as possible.

4. Dispose of Everything

Carefully fold up your plastic sheeting, and seal it in a heavy trash bag. Dispose of coveralls, brushes and any other contaminated gear the same way. Keep bagged items stored outside until trash pickup.

5. Control Crawl Space Climate

There are several different ways to address crawl space climate, but a dehumidifier is usually the most effective and affordable solution. 

Consider installing a model designed to operate in tight places. Make crawl space inspection a part of spring and fall home maintenance.

Methods to Avoid

To prevent health risks or further damage to your home, avoid these mold removal methods: 

  • Painting or caulking over mold. Painting or caulking over mold only conceals the issue without killing the mold at the source.
  • Excessive scrubbing. Scrubbing on porous surfaces can release mold spores into the air, leading to mold proliferation and regrowth. 
  • Addressing mold without proper PPE. It is imperative that safety precautions, like wearing gloves and masks, are taken while handling mold-infested areas. 
  • Tackling restoration jobs that are too large. Don’t risk taking on a mold removal job that’s too large or dangerous. We strongly recommend calling in a mold remediation service if the affected areas include damaged or rotted wood, mold covers multiple areas larger than 3 square feet, or you or any family members deal with allergies or respiratory problems.

Bringing in a mold remediation specialist also addresses issues like identifying and eliminating mold sources and repairing and replacing affected materials.

What are the Signs of Mold in Crawl Spaces?

moldy baseboards

A humid crawl space creates the perfect environment for mold. It quickly permeates wood, causes structural problems and can even impact your health.

These four clues are signs of mold growing in your home’s crawl space.

1. Strong, Musty Odors

Unpleasant mold odors continually migrate upward and through the first floor.

2. Allergic Reactions

It’s not unusual for mold under the house to cause allergic reactions, including runny noses, itchy eyes, headaches and respiratory problems.

3. Moldy Baseboards

As mold spreads from the crawl space, it affects the baseboards on the floor above.

4. Bouncy Floors

When the crawl space is excessively moist, the humidity rots wood and prompts mold growth. It can also weaken the structure of your floor joists, making them less stable and causing them to feel bouncy or springy when you walk across the floor.

5. Pests

Lots of pests love the moisture and humidity that goes along with mold growth. If you suddenly notice pests like spiders, crickets, termites, slugs, millipedes, or centipedes in your home or crawl space, it’s likely that there’s mold present. 

6. Discolored Crawl Space Components

Mold growing on crawl space walls, posts and floor joists appears as fuzzy, slimy or powdery patches.

Look for these color-coded clues.

  • Black – Most common molds, including Alternaria and Cladosporium
  • Green – Also very common, may be Aspergillus, Cladosporium or Penicillium
  • Greenish Black – Slimy in appearance, dangerous Stachybotrys chartarum
  • White – Variants of Aspergillus, Cladosporium and Penicillium
  • Brown – Common Aureobasidium pullulans or Pithomyces chartarum
  • Yellow – Wood-damaging Serpula lacrymans or Epicoccum nigrum
  • Orange – Variants of Serpula lacrymans

Preventing Mold in Crawl Spaces

mold in crawl space

These six tips reduce the chances of mold invading your home’s crawl space.

1. Look for Leaks

Inspect the crawl space at least twice a year. A small leak that goes unnoticed sets up an ideal environment for mold. Check under the house after plumbing problems upstairs too. Water always flows down, so stay on the lookout.

Power Tip: Head off crawl space flooding by installing a sump pump.

2. Insulate Against Condensation

Insulation protects pipes from freezing, but it also keeps condensation from forming on pipe surfaces. Otherwise, fluctuating temperatures result in wet pipe exteriors that become a source of moisture for mold growth.

3. Fix Foundation Cracks

Dampness often finds its way into the crawl space through hairline cracks in foundation walls. Small foundation repairs head off big mold problems that can spread up and through your home’s beams and subflooring.

4. Fight Mold with Ventilation

Once fungal growth takes hold, it thrives in the wet, stale atmosphere under your home. Ventilating the crawl space circulates fresh air through the area and holds down humidity. That reduces the concentration of air-borne spores, making it harder for mold to spread.

Power Tip: Make sure the clothes dryer vent terminates outside the crawl space.

5. Install a Vapor Barrier

A vapor barrier doesn’t completely eliminate moisture in a crawl space, but it does lay down an important layer of protection against mold. The plastic membrane helps control dampness that naturally rises up into the house, affecting wood, flooring, drywall, insulation and indoor air quality.

6. Reroute Rain Water

Make sure downspouts do their job by directing their flow at least 6 feet away from the house. Add concrete splash blocks to prevent heavy rain from pooling around the foundation. These easy tips lower the chance of crawl space flooding, and that lowers the risk of mold growing under your home.

Dealing with Crawl Space Mold in Chicago, IL, or Suburbs? We’re Here to Help!

If you decide to take on mold in the crawl space, removal techniques are very important, so please follow our guidelines carefully. We want you to stay safe. Wear protective gear, and take your time.

Don’t hesitate to call us if you have any second thoughts about doing it yourself. We have years of experience with crawl space cleaning services in Chicago and the suburbs. Our services cover residential and commercial properties, and our team members are industry-certified in mold removal and remediation.

When the job makes you think twice, call us first here at ServiceMaster Restoration by Zaba: 773-647-1985

Is white mold common in crawl spaces?

Yes. White mold thrives in places that are dark, damp, and humid. Since crawl spaces provide all of these factors, white mold is common in crawl spaces and basements. 

Is it safe to touch mold barehanded?

No. Molds produce allergens, irritants, and potentially toxic substances known as mycotoxins. While not all molds pose a threat, certain types can trigger allergic reactions or respiratory complications, particularly in individuals with pre-existing sensitivities or allergies to mold. If you need to touch mold, you should always use protective equipment, such as gloves and a mask, to limit direct exposure to mold spores and prevent inhalation.

Can I vacuum mold?

Possibly, but only if you use a vacuum equipped with a HEPA filter. Non-HEPA vacuums lack the filtration systems needed to trap and contain mold spores, so when you use them on moldy surfaces, they actually disperse more mold and mildew spores throughout your crawl space. These microscopic spores will grow where they land, which can make the mold problem worse. Because of this, it’s essential to always use a vacuum with HEPA filtration if you want to vacuum mold.

How much mold in my crawl is acceptable?

Mold is a natural part of our environment, but it doesn’t belong in your crawl space. Even a small patch rapidly spreads as it feeds on the structural components directly under your home.
Airborne mold spores can also migrate into the house and impact the health of everyone upstairs. There are no acceptable levels of mold in a crawl space.