Wednesday, June 19, 2024

How To Control Mold In Crawl Space

Bonus Step: Do You Already Have Mold What To Lookand Smellfor

Crawl Space Mold Removal Tips | DIY Mold Remediation Crawl Space

As delightful as crawl spaces may be for mold, they can be dangerous for humansfostering the spores and splotches that can provoke allergic reactions, degrade the structural integrity of their homes, and cause unseemly stains and smells.

Worried that you might have mold in your crawl space? Here are some common signs that may indicate that youre dealing with a mold infestation:3

  • Warped or stained baseboards
  • An earthy, musty scent thats coming up from below
  • You or your family members experience cold-like symptoms unrelated to a virus, including runny noses, irritated throats, or headaches

How Can I Prevent Crawl Space Mold

Though mold is everywhere, it wont cause problems if you eliminate conditions that encourage its growth. Routine inspection can help you uncover issues that could create the perfect condition for mold to thrive.

If the crawl space is vented and not sealed, its about time you seal it and block all vents. Your open crawl space allows mold to come in attach itself to wood and other organic materials. Since this place is typically moist, its going to grow fast and infest the whole crawl space. Your basement and crawl space repair contractor is going to install a plastic vapor barrier that covers the entire floor and walls. It can go around barriers such as wooden beams and piers.

Check and remove damaged or torn insulation from the crawl space as its likely to get wet and harbor pests. Mold can easily attach itself to the damaged material. In no time, it can take over and spread to other parts.

Ensure that all water pipes and ducts that run through the crawl space are intact. Fix any pipe thats leaky. Take a step further and insulate your water pipes to stop condensation during cold winter weather.

Cracks on the crawl space wall may also encourage moisture and water to seep in. And thats bad news as it will also encourage mold to grow. Typical repairs may involve applying crack injections to seal up crevices on the wall.

Using A Surface Blaster

A surface blaster is much like a sand blaster in that it will remove the mold from all surfaces by bombarding it with high pressure particles. You can likely rent or buy one from your local hardware store.

Once youve become familiar with the operational instructions, fire the blaster up, and aim the wand directly at the area from 2 feet away. Evenly blast the surface.

Despite the use of such a high powered machine, surface blasting mold is actually a much longer process than other options, as you will be blasting every single nook and cranny in the crawlspace. The upside is, once youve put in this time and work, it will completely remove every last trace of mold.

Recommended Reading: How To Test For Mold Air Quality

Is Crawl Space Mold A Health Problem

In one word Yes. Mold is an insidious, invisible predator in your home. It hides in places no one ever thinks to look like under cabinets, in crawl spaces, and behind furniture. People may spend weeks, months, and even years fighting illness, and never know what they are really fightingmold. Many of our customers find us after a recommendation from their doctor, that they may in fact have a mold problem, and not just an illness.

Mold is most often associated with allergies, but mold is much more menacing than people know. While all molds have the potential to cause irritation and allergy symptoms, molds can also cause much more dangerous health problems including: fungal poisoning and mental health problems.

To learn more about how mold can affect mental health check out our articles: Mold and Mycotoxins: Effects on the Brain and Nervous System in Adults and Effects of Mold on Childrens Health.

Paying For Mold Remediation

The Home Inspection Process

For those who are going to DIY their mold problem, the costs include purchasing cleaners, tools, and personal protective equipment. This is generally a more affordable option than calling in mold remediation specialists, but you may not be thorough enough in your cleaning. This could lead to a recurring mold problem down the road. Bringing in the professionals may be a better investment in the long-term.

The size of the mold contamination, as well as the materials that have been damaged or infected by the spread, impacts the cost of removal. Access to the area and the extent of the damage as also significant factors. Smaller infestations could cost as little as $500 for removal services, while more severe problems can cost upwards of $30,000 for complete treatment and repair of the crawl space or floor joists. Unfortunately, most homeowners insurance policies will not cover remediation services unless the infestation can be linked to a covered incident like water damage or flooding.

For experienced help with removing mold from your crawl space, contact the team at Mold Remediation. They are experts at removal and cleanup services for both residential and commercial buildings.

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Put Down Plastic Over Dirt Floors

Install a 6-mil or heavier poly / plastic vapor barrier over the dirt surfaces and up walls about a foot ideally you’d seal or affix the plastic to the walls.

Plastic will break the natural “moisture pump” that occurs when wet soil is below a building:

moisture evaporating into the air above the soil actually acts as a pump to draw more soil-moisture upwards: the dirt under the building, fed by an outdoor moisture source or by indoor leaks, continues to pump moisture into the structure.


Our photo shows a white moisture barrier over the soil of a crawl space where a significant mold reservoir has been removed from the wood surfaces above .

You’ll note the shiny appearance of the wood.

The mold remediation contractor who handled this job elected to seal the wood surfaces after the cleanup was complete.

Does Crawl Space Encapsulation Qualify For A Tax Credit

Crawl space encapsulation does indeed qualify for a tax credit. The American Recovery and Reinvestment Act bill that was passed in 2009 states that you can get up to $500 in tax credit when you improve your homes energy efficiency.

This is great news since the project can cost a lot of money, so having this financial reward sure helps!

However, even if that wasnt the case, the return on investment that you initially put in this project will show within years, even months, of energy bill savings. So its a sound decision all around.

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  • |#1


    I’m afraid I don’t have any useful advice and hopefully someone else can chime in, but for others building similar un-vented crawlspaces: The surface of the area should be sloped to a floor drain. The vapour sealing of the floor, as well as any insulation that is going to be added, should be done before the framing above commences.

  • |#4

    Thanks Malcolm. We live in a relatively dry climate and are building on a site that is not susceptible to high ground water, etc. For these and other reasons, we made the decision not to use a scratch coat or include a floor drain. Maybe that was a mistake. We also didn’t complete the sealing, in particular installing the vapor barrier membrane, because we didn’t want to walk on it during installation of the floor joists. We could complete it now before we put the subfloor on, except for the snow issue.

  • Expert Member|#7


    I would consider adding a floor drain while you still can. In most areas of the US, and in all of Canada it is required by building codes.

    “The surface of the crawl space floor must slope to a drain or sump pump. Any drain located in the crawl space must be allowed to run off and terminate outdoors or to an interior crawl space drain or sump pump. Crawl space drains may not run off to gutters or foundation perimeter drains, and dryer vents must be terminated outdoors. As a more general observation, any building grade should allow water to drain away from the foundation of the crawl space .”

  • Outside Air Through Open Vents

    Crawl Space MOLD REMOVAL Tips – Kill MOLD in your crawlspace – Twin Plumbing

    In the past, builders tried to dry the crawl space out and prevent moisture problems by adding vents to the foundation, but more recent studies have shown that crawl space vents do more harm than good. The vents let in hot, damp air – and they can also let in water.

    What happens in a vented crawl space on a humid summer day?

    Let’s say the air in the crawl space is 68 degrees F and the surface temperature of the walls, dirt floor, and floor joists is 62 degrees Fahrenheit . And the air coming in through the vents is 77 degrees F with 80% relative humidity.

    The relative humidity is how full of water the air is relative to the maximum amount of water it can hold at a given temperature. For every one degree that the air is cooled, the relative humidity goes up by 2.2%.

    The difference between the temperature of the crawl space surfaces and the outside air is 15 degrees F. When we multiple 15 degrees F by 2.2%, we get a 33% increase in relative humidity where the outside air comes in contact with the surfaces inside the crawl space.

    When we add 33% to the original 80% relative humidity, we get 113% relative humidity. At 100% relative humidity, the air cant hold any more water and it releases moisture in the form of condensation.

    Lower humidity doesn’t mean you’re in the clear.

    Mold and fungus caused by moisture are just a few of the ways a dirt crawl space negatively affects your health.

    Read Also: How To Remove Mold From Clothes With Hydrogen Peroxide

    Tip : Adequately Ventilate Your Space

    Good ventilation airs out your crawl space, and in conjunction with a vapor barrier, is very effective in keeping everything perfectly dry. There are multiple ways to ventilate the area, such as:

  • Divert a minimal amount of heated air from your HVAC system to the crawl space.
  • Install a dehumidifier. Humidity levels shouldnt be above 30-50%.
  • Install an exhaust fan to move crawl space air outside.
  • If you have a clothes dryer in your home, ensure the vent flows outside the crawl space.
  • Check For & Clean Or Remove Other Mold Contamination Or Other Mold Friendly Stored Items

    Besides looking at the mold on the dirt floor, be sure to also check wood framing, wood subflooring, any stored items such as boxes.

    Note that insulation may be moldy even if it looks clean, particularly if the insulation has been exposed to a large area of mold growth on wood, paper, or other mold-friendly materials nearby.

    Remember also to remove junk stored in the area that invites mold growth such as cardboard boxes, old furnishings, and that Barbie townhouse that was left by your kids back in 1982. If fiberglass insulation has been exposed to high levels of airborne mold on wood surfaces it’s probably best to remove it, clean the surfaces, and re-insulate once the area is dry and clean.

    An example of using media blasting to clean wood surfaces in a hard-to-access area is


    Mold on Crawl Space Dirt? Look Up!

    More significantly, the conditions of moisture and presence of organic matter such as wood framing and also hospitable moisture holding materials such as fiberglass insulation all mean that where you see mold on dirt in a crawl space you should be looking “up” to inspect the building walls and floor structure overhead for other mold growth that could be a problem.

    also USING LIGHT TO FIND MOLD – how to use light when looking for mold.

    In any event, ne would want to be careful not to get mold in a cut, or in your eye, even if it does not appear to be an airborne species that can be easily inhaled.


    Also Check: What To Use To Clean Mold Off Wood

    Is It Better To Hire A Contractor For Crawl Space Encapsulation Or To Do It Myself

    Taking on the project of crawl space encapsulation yourself might sound tempting, especially since the cost of hiring a professional could sound too high.

    However, you should keep in mind its not an easy job to do. The process can take several days even when you have a team of 23 highly-skilled professionals, and thats a full 8 to10-hour workday.

    This project, most of all, requires meticulousness. You cant just throw insulation materials in there and hope for the best. It requires careful planning as well as top-notch safety precautions.

    A reputable company will also give you a 15 to 20-year warranty on the encapsulation job. So should anything go wrong, you can ask for a do-over or a repair. In my opinion, this is the biggest selling point for hiring a contractor for crawl space encapsulation.

    Rest assured, though, that you can accomplish the task if you live in an area where you wont need a flawless seal, like dry areas with low humidity. Its also much easier to do this job yourself if your house doesnt have a large crawl space, less than 2000sf is ideal for a DIY job.

    Does Crawl Space Encapsulation Stop Rodents

    Crawl Space Repair

    This is another issue that most homeowners consider encapsulating their crawl space because of. Rodent and insect infestations usually happen when theres a lot of standing water or torn and tattered insulation to nest in.

    If you hear sounds of scratching or chattering in the night, chances are theres a family of rodents that made its way into your crawl space. There are also reports of crickets that chime constantly after they infest the area, which makes a good nights sleep pretty difficult.

    Encapsulation will effectively eliminate any chances of rodent or bug infestations, since all entryways into the crawl space are sealed shut. The issue of standing water will also be taken care of thanks to the presence of a sump pump and/or a dehumidifier.

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    What Is Crawl Space Mold

    The mold in your crawl space may be one of a number of different types. Mold spores are found commonly in the air and soil. A few of the common environmental molds you may find in your crawl space and house are:

    Each of these different types of mold are commonly found in the environment. The spores from these different mold species can live and travel in the air, and in the soil. Unfortunately, the environment in crawl spaces provides a perfect place for mold growth to flourish.

    Mold requires moisture to grow which tends to be plentiful in crawl spaces. Water damage, plumbing leaks, or water seeping in through the foundation walls can all contribute to moisture problems underneath your house. Mold feeds on the sugar and starch that is found in wood, called cellulose, which is usually found in the structural elements underneath houses. With these conditions, mold growth can happen fast.

    Many types of mold can be hazardous to human and animal health, so you want to be sure to get rid of any mold before it has a chance to spread into your home. Crawl space mold has a number of adverse effects including:

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    How Mold Gets Into Your Crawl Space And What It Means

    So, perhaps you have found a bit of mold on floor joists in your crawl space, and now you want to avoid making the same mistake again. And, if youre freaking out, relax. As long as youve caught it early, youll be fine.

    Mold is pervasive in buildings and places with a lot of moisture. It is found indoors and outdoors, entering your home through doorways, windows, and vents. When mold spores drop on any place with excess moisture, they grow, and many building materials provide all kinds of nutrients that encourage mold growth.

    However, the problem with mold in your crawl space is that it isso close to your foundation, and the consequences of it getting out of hand can be devastating. You could lose entire rooms of your house or get seriously injured, over and above the respiratory issues, it causes.

    Mold loves crawl spaces, and it happens to the best of us. It just means there has been a moisture buildup in the area. You now have to find a way to get rid of the mold and prevent it from happening again.

    Now that youve done an adequate inspection and have our tips for controlling mold inside crawl spaces, you can identify and fix the problem. And then you can get to removing the mold.

    Read Also: How To Clean Black Mold On Shower Grout

    Crawl Space Mold What Are The Signs

    Some homeowners in Orlando, FL, may not know the risks that crawl space mold poses to their health. Others might not be aware of the signs of mold. If you notice any of these signs in the crawl space, it could be an indication mold has taken over that space.

    • Green/black spots or water stains on baseboards are a clear sign of moisture problems.
    • Warped wooden floors, peeling wallpapers and a lingering musty smell are indications of a potential mold issue.
    • Rotting/decaying wood joists or beams in the crawl space
    • Unexplained illnesses accompanied by a runny nose, itchy eyes, persistent coughs, and breathing problems.

    Types Of Crawl Space Mold

    Best Way to Dry a Crawl Space for Mold Removal

    Your crawl space is likely to attract three types of mold, each with a varying degree of risk. Black mold is the most common and also the deadliest. It appears dark gray or greenish at times. And it can be fuzzy or powdery. Two strains exist: Stachybotrys atra and Stachybotrys chartarum. Both release mycotoxins that can cause serious allergic reactions.

    White mold is another type that can grow in the crawl space. It mostly sprouts on exposed soil and wooden joists and appears fuzzy. While not as dangerous as black mold, it still has the capacity to release toxins that cause health problems.

    Regarded as the house-eating mold, the yellow type feeds on wooden structures and organic materials causing them to decay and deteriorate. Yellow mold usually appears flat.

    Whether its white mold youre dealing with or the more serious black mold, its good to know how mold gets into the crawl space and what effects it has on your health so you can take appropriate measures, including crawl space vapor barrier installation, to protect yourself.

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