7 Steps for Cleaning Mold on Floor Joists in Crawl Space

Helen Skeates
Helen Skeates
11 min read

Isn’t it common knowledge that mold can be found in a basement? You may ask how to get rid of mold on floor joists if you spot it in your home.

As long as the air is moist enough for mold to grow, humidity can lead to the growth of the fungus. Getting into a crawl space via inhaling water vapor from nearby soil or concrete is rather usual.

Mold can grow in a variety of places in your home, but your floor joists are particularly vulnerable to it if you live in a humid region. Both basements and cellars are at risk of developing this issue.

An untreated problem might quickly escalate into a major one. Stopping spores as soon as they appear is the greatest strategy for getting rid of them completely. You may do this by following a few simple steps.

What Causes Mold Growth On Floor Joists?

Most floor joists are made of wood, which is a porous building material. Water can swiftly penetrate the fabric, causing structural degradation, and this can happen very quickly.

Mold development is triggered by water damage. Learn how to recognize black mold for additional information on mold growth. One of the many causes of wetness in basements is excessive moisture, which is common due to poor air circulation.

How to Get Rid of Mold on Floor Joists in Crawl Space

Keeping mold from forming in your basement and on your floor joists can be a difficult task. Moisture is more likely to build up in basements than in any other component of the house. Another basement mold removal guide is available here.

White is the most common color. Mold thrives in a crawlspace that hasn’t been properly treated, especially in areas with a lot of rain.

When inspecting your crawl area, look for mold or mildew forming between the joists of your floorboards. Mold and mildew can not only wreak havoc, but they can also spread disease. Inhaling and exhaling infected spores from a crawl space can lead to respiratory issues and unpleasant odors.

7 Steps for Cleaning Mold on Floor Joists in Crawl Space

Physical labor is required to remove mold from the basement’s crawl area and from between the floor’s joists. Sponging and maneuvering in cramped quarters are required. Because of these working conditions, you will need the necessary property safety gear and cleaning products to get the job done swiftly and without putting your health at risk.” Protect yourself with the following:

  • Goggles
  • Gloves with a textured surface grip
  • Asthma or dust/chemical face mask
  • Clothes that keep you safe

Cleaning supplies are also necessary:

  • Roofing made of plastic
  • containers containing five gallons
  • In a cannister
  • Disposable rags and sponges
  • An old toothbrush, a putty knife, or even a small shovel can be used for this purpose.

You must first choose the method you will employ to remove the mold from the crawl space before moving on. Making your own cleaning solutions at home is an option for some people. Mold can be removed with ammonia, bleach, tea tree oil, or vinegar. Commercial-grade cleaners, such as those used by mold treatment companies, are also available to the general public.

Regardless of what method you choose, you must be diligent and systematic in your efforts to remove the fungus. Get started with mold eradication with these instructions:

  1. Before you begin, put on your safety gear, such as gloves or goggles, and make sure your hands are clean.
  2. To remove mold, use the indicated solution concentrations. You can make a paste out of two parts baking soda, one part white vinegar, and one part water. A vinegar-based cleanser, which is easier to spray, may be preferable if you have a broad area of growth. A strong solution of one cup of borax to one gallon of water is safer than bleach or any other chemical. In order to make bleach more safe, dilute it with a quart of water and half a cup of bleach.
  3. Use plastic sheeting to cover any holes, such as air conditioner vents or doors. As a result, mold spores are less likely to spread throughout the home. When working with chemicals or fumes, it’s especially important to have adequate ventilation in the crawl space. Set up a fan that blows air away from where you’ll be working, preferably toward the outside. As a result, more air is created, which speeds up the process of removing the moisture.
  4. Scrape or remove any significant mold growths you observe using a little brush or the flat side of a putty knife. These can either be thrown away or scraped up with a spoon. Once you’ve finished with the floor joists and other areas, you’ll need to disinfect the dirt.
  5. Using a cleaning solution of your choice, douse the affected area. Soak the area, but not to the point of causing irreversible harm to the wood. For best results, wait at least five minutes before scrubbing the affected area. Splinters from wood can be a safety threat and cause a cleaning cloth to snag, thus a brush is the best option for cleaning wooden surfaces. Scrub the surface again and again until no more mold is evident.
  6. As you make your way out of the crawl space, use your cleaning solution to mop up any remaining dirt. Helps inhibit the growth of any mold spores that have landed on the floor. It’s possible to eliminate up to 90% of the fungus in the crawl area with vinegar, bleach, and other liquids that evaporate. A pump sprayer or a spray bottle can be used to disinfect hard-to-reach areas.
  7. Once the infected areas have been washed and drenched, a UV lamp can assist kill any spores that may still be present. The dirt floor should be exposed to sunlight for at least a day. Additionally, this helps dry up the area, preventing further mold growth in the future. Fans can be used to circulate the air and remove any lingering scents from mold or cleaning treatments.

Get Rid of Mold on Floor Joists in Crawl Space: In 7 Easy Steps

Assessing Damage From the Mold Growth

In addition to health concerns, mold poses a serious threat to your house. Mold can cause major structural damage to your home’s floor joists, floorboards, and other supporting structures if it is not handled. Moisture-retaining wood deteriorates quickly, and a mold infestation exacerbates the problem. As the fungus eats away at the wood, it can cause the boards and beams to split apart. Until it’s too late, you may not be aware that your flooring is harmful.

It’s imperative that you inspect the area for damage after you’ve finished removing the mold. Determine if there are any soft patches or regions of degeneration in the joists or boards. In order to ensure the safety of your home, you should get any structural issues assessed by a skilled contractor.

How to Tell If Your Floor Joists Has Been Infected With Mold

If you don’t know what mold looks like or how to get rid of it, you’ll have a hard time preventing it from spreading.

There are more than 100 different kinds of mold, each with a distinct set of symptoms. Floor joists infested with mold can be detected using this method.

Musty Odor

There is frequently a musty and wet smell in the air as the first indicator of a mold infestation. During the growth of the spores, they begin to emit a musty and wet odor. Before you can even see the development, you’ll notice a distinct odor.

Crawl space smells can be detected in the house or at the vents or entryways to this section. Even the best air fresheners can’t always mask mold’s musty odor.

Problems With Your HVAC System

A mold infestation in your home’s subterranean space can migrate to the HVAC system, as well. As a result, the musty smell and spores it leaves behind might spread throughout the house, leading to an infestation in additional rooms.

Structural Damage

A mold-infested home is a result of its organic elements. When a mold colony grows and spreads in your crawl space, it can degrade wood, paper, fabrics, or glue.

IFrameThe supports and materials in your crawl space can be seriously harmed by mold, putting your home’s safety and structural integrity at risk.

As the growth of mold spreads over the floor joists or up into the floorboards, the flooring, ceilings, and even the walls may break and fall due to the damage they produce.

Cleaning Wood Joist in Crawl Space with Mold - Tasteful Space

Health Risk

There’s a chance that a mold infestation in your home, even if it’s underneath the structure, will be harmful to the health of the individuals who live there. Be aware that mold spores aren’t isolated to one place, but can travel through the air.

Asthma and allergy sufferers are particularly vulnerable to the dangers of inhaling mold spores and residing in a mold-infested environment. People who have never been allergic to mold are at risk of developing severe allergic reactions when exposed to mold.

Mold exposure can cause symptoms that resemble an upper respiratory infection, such as sneezing fits, runny or stuffy noses, postnasal drip, sinusitis, and even skin rashes, among other things.

The intensity of symptoms is determined by the amount of exposure one has had. If you see a dramatic improvement in your health when you’re away from home, you should check for mold in your home.

IFrameMethods for Preventing Mold Growth in Crawl Space Floor Joists

Because prevention is always preferable to cure, you must do everything in your power to halt the spread of mold as soon as it begins. You just need to know where to look to prevent mold growth in the floor joists of a crawl space. To assist you, here are a few pointers:

  • Mold can grow in your basement if you don’t know how to control moisture. Keeping your basement and crawl space dry will help you avoid more expensive repairs in the future.
  • In comparison to other parts of your house, the crawl space is more likely to become damp. A dehumidifier can assist keep the room dry by removing excess moisture from the air. Between 35 and 50 percent humidity is ideal for most houses.
  • Another thing you can do to prevent mold in your floor joists is to make sure your air is circulated properly. Warm, damp air can accumulate in a space if it isn’t properly disposed of.


If you’re still having trouble after following the instructions for removing mold from floor joists, call in a pro.

Helen Skeates

Helen Skeates

Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.