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Don't Let Mold Creep Up On You - Crawl Space Dehumidifiers Keep You Safe!

Crawl Space

There could be a serious danger lurking in your home! You might not know it's there until you start having allergic reactions, irritations and even flu-like symptoms. So what's the culprit? It's mold. In small amounts it isn't very harmful. If it grows in regularly used living spaces it's easy to notice the discolored spots on your furniture and walls so it doesn't have a chance to spread.

Unfortunately, there is one space in your home that mold can go unnoticed, allowing it to grow at a rapid pace. This is in crawl spaces. These spaces can exist throughout your home like the attic or basement. Since they aren't easily accessible we don't use them very much. If mold started to form we'd probably never know until it started to affect your health. Even then it might take a while to realize what the source is.

Usually mold exists because there is excessive moisture present. If this is the case then you might have other things to worry about as well. High humidity is the preferred environment for bugs and pests. It can also compromise the structural integrity of your home. Wood can begin to rot, floors sag and metal begins to rust and deteriorate.

Fortunately, if you notice the moisture early enough you can prevent these issues from happening. The simplest solution is to dry out the space with a crawl space dehumidifier.

There are five steps you need to take for eliminating excessive moisture and installing a dehumidifier for your crawl space.

Five Steps for Eliminating Your Moisture Problem

1. Find the Source

First, eliminate the source of the problem by determining how moisture is getting into the space. There is no point in trying to start cleaning up and drying out a space if it is just going to keep accumulating more moisture in the future.

  • Is it a leak in the roof, siding or basement?
  • Has a pipe broken?
  • Are your floor drains backed up?
  • Do you live in an area with high humidity?

Thoroughly inspect your home from roof to basement to determine where the water is getting in. When you figure out what the source is you will need to correct it immediately.

If the source is high humidity then continue with the below steps before using any airflow equipment like a dehumidifier as this could just spread mold even more.

Mold in Corner of Basement

2. Assess the damage

Once the source of the leak is corrected check the space to determine what kind of damage has been caused. You'll need to look for signs of mold, pests and damage to the structure. Some of these factors can cause hazardous conditions that can be harmful to your health so it's important to wear protective equipment, use a flashlight and don't work alone.

How to identify if you have any unsafe or unhealthy conditions associated with excessive moisture:


  • Mold or mildew odor - This can be an unpleasant, musty smell like leaving wet clothes in a washer for too long. This is because the mold spores emit a gas as they grow. It is more noticeable in a crawl space since the smell can be more concentrated in a small, closed-off space.
  • Visible signs of mold - This might seem obvious but some people can't distinguish mold from dirt or soot. Some mold looks white and thread-like. Other mold can appear as clusters of small black spots. Mold can be all sorts of colors including black, gray-brown, gray-green, white or even orange, pink or purple if it's behind wallpaper.


  • Ants - These are an especially big problem in crawl spaces. Black carpenter ants in particular are a real problem for home damage. Look for sawdust or droppings as a sign that they've entered a space.
  • Termites - Pale in color with soft bodies, sometimes with wings. They like to continuously eat wood. Watch out for signs of blistered or wavy wood, mud tubes or tunnels and sawdust-like residue.
  • Beetles - There is one particular family of beetles that are wood borers and can cause some serious structural damage to homes. They are particularly attracted to wood that isn't covered with paint or varnish, so crawl spaces under floor boards are very appealing to them.

Structural problems

  • Sagging floors - This can sometimes occur in older homes due to foundation settlement, but it can also occur because of excessive moisture. It might not look obvious to the eye, but if you notice doors or windows not shutting properly because the alignment is off then it might be due to sagging floors.
  • Rotted wood - When moisture levels are high enough fungi can develop and start digesting the proteins and sugars in wood. It will start to powder, splinter or come apart in sheets. If caught early enough it won't cause too much damage, but if it goes for too long the consequences can be severe. Wood rot is often referred to as "house cancer." Any wood affected severely enough will need to be completely replaced, which can be very expensive.
  • Rust - This can form on metal pipes and if left untreated could start to weaken the pipes, eventually causing them to break. This could just cause another water problem down the line.

3. Cleanup

The next step is to clean up the space. Remove any debris, junk and wet materials. This is necessary in order to make the drying out process easier. Now that the space is clear, remove any standing water. Depending on how much water there is you might need to use a sump pump to pick up the water.

Cleaning Glove

If signs of mold exist

If there is any mold present it is very important that you clean it up before you start to use any airflow equipment like a dehumidifier. This will just spread the mold and also contaminate the equipment.

The United States Environmental Protection Agency (EPA) provides A Brief Guide to Mold, Moisture, and Your Home. It contains some basic information about mold, cleanup guidelines, and prevention and control tips. Because mold can be harmful to your health it's best to inform yourself on the proper procedures for cleaning it up. If the area has more than 30 sq. ft. of contamination then it should be cleaned by a professional mold company.

If signs of pests exist

Be sure to clean up any rodent or other pest droppings as there may be a bacterial or viral hazard. You can use a black light to spot any urine stains on surfaces including dirt floors. If urine does exist on a dirt floor then it might be necessary to remove the layers of contaminated soil. Sanitize any contaminated surfaces. Then spread a plastic covering over dirt or gravel surfaces.

Remove any dead tree limbs around your house because this can be a source for ants, termites and beetles.

4. Keep the space dry with a dehumidifier

Now that you've taken care of the water entry problem and any issues of mold and pests, you can start to dry out the space. The fastest and easiest way to do this is with a crawl space dehumidifier.

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First, you'll need to figure out what size dehumidifier is best for the space. You can click here to find out what capacity unit you will need based on the square footage of the space and the moisture conditions present.

Now that you've figured out the dehumidifier size you'll need to determine what type of unit to purchase. This all depends on what kind of moisture problem you have. Is it a one time incident due to a leaking roof, burst pipe or faulty drain? Or is it due to something more on-going like living in an area with high humidity?

If the problem is long-term because of high humidity then you might want to consider installing a permanent crawlspace dehumidifier. In this case you'll want to get a model with a continuous drain pump that you can connect to a drainage system, so you won't need monitor a water collection tank.

Otherwise, if your problem is more temporary, then a portable unit without a pump will work just fine; it will be easier to maneuver and won't require installation. Use it until the humidity has reached a healthy level -- just be sure to empty the water collection tank periodically.

What is a good humidity level?

A good humidity level is anywhere between 30% - 50%. Anything above 50% is considered too high and can become a breeding ground for mold and pests and start to compromise the structural integrity of your home. You can purchase a dehumidifier with a built-in humidistat to control the humidity level or you can purchase a hygrometer that will tell you what the level is.

5. Perform regular inspections

Whether your problem is temporary or on-going it is still important to do regular inspections of the crawl space to make sure the moisture problem hasn't returned. You'll also need to regularly clean and maintain the dehumidifier ensuring that it will continue to function properly. Here is a helpful guide on How to Properly Clean a Dehumidifier.

A Safe and Healthy Home

It may seem like a hassle trying to rid a crawl space of excessive moisture. However, this is a problem that needs to be taken care of immediately by simply using a dehumidifier. If it's taken care of sooner rather than later, you can prevent mold from forming, pests from taking over and avoid damage to the structure of your home, which can be very expensive! Ultimately, what's most important is ensuring that you and your family are safe and healthy.

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