Why Does My Crawl Space Have Mold?
One of the core problems that humidity causes is high moisture levels, which in turn can lead to mold growth.
One area of your home susceptible to mold growth is your crawl space.
Crawl spaces are popular because they tend to be cheaper than laying a foundation for a basement slab; make it much easier to access pipes and other utilities; and if the soil is unstable, it is simpler to install a crawl space by bringing the house up to or above ground level.
The core problem with crawl spaces, however, is they provide the ideal environment for mold to thrive because they are dark, dirty, and humid.
Mold is a fungus that requires moisture and high humidity to grow and thrive. Like plants, mold has cells. However, unlike a plant that has chlorophyll and is able to makes it’s food through photosynthesis, mold can not feed without moisture.
Mold reproduces by releasing it’s spores, meaning mold can spread quickly in a crawl space, especially if the temperatures range between 41 degrees Fahrenheit up to 100 degrees Fahrenheit, common in the DC Metro Area. The final ingredient mold needs to thrive is food, high cellulose materials such as wood, dust, and dirt, ample in a crawl space.
This article has two key goals.
First, we will explain why your crawl space could be contaminating your indoor air because of mold growth and excess humidity.
Second, we will explain what you can do to fix the problem.
Top 3 Frequently Asked Questions About Crawl Space Humidity!
What is the threshold humidity level for mold growth?
When the relative humidity of your crawl space is 70% or higher, mold can thrive.
“Relative” humidity is the humidity level expressed in a percentage of the amount of moisture in the air needed for “saturation” (i.e. the highest level of humidity – 100%).
The amount of water the air can hold (humidity level) is dependent upon the temperature of the air itself.
When the humidity level begins to creep up past 70% relative humidity, this provides the perfect environment for mold growth!
My crawl space has condensation. What does that mean?
Condensation is an indication that the air within your crawl space has reached 100%.
The air can no longer hold the moisture and it’s condensing onto the surfaces, causing the organic materials that make up your crawl space to become damp, which will result in mold growth.
How do I know when the humidity level is too high?
The easiest way to determine the relative humidity of your crawl space is to use a hygrometer or you could install a digital thermo-hygrometer with a remote sensor to track it.
Using this tool to measure the humidity of your crawl space is a great way to monitor the amount of moisture present.
A thermo-hygrometer measures both temperature and humidity level.
These devices are even more ideal for crawl space atmosphere monitoring because the relative humidity level is contingent upon the moisture in the air in relation to the air’s temperature.
Being able to track the changes in both of these conditions in your crawl space will allow you to see trends and anticipate necessary changes.
For instance, if the weather is hot during the day but the temperature plummets at night, this can cause problems for your crawl space’s humidity levels. The daytime temperature is higher, which allows the air to hold more moisture. As night approaches and the air cools, the amount of moisture the air can hold also decreases – causing the relative humidity level to rise. A crawl space that was at a permissible humidity level during the day can run into problems when night falls.
Being able to see these changes on your thermo-hygrometer can help you identify these types of trends so that you can respond appropriately.
Keep in mind that properly insulating your crawl space and installing vapor barriers will help regulate the temperature and keep moisture levels down, resulting in less fluctuations in the air’s relative humidity.
Top 3 Reasons Your Crawl Space Has High Humidity Problems!
- Water Accumulation. If your crawl space has standing water, you probably have a drainage problem or a plumbing leak. This needs to be fixed immediately. You do not want water to accumulate in your crawl space because this will compound your potential mold problems, not to mention as mold grows it will impact the indoor air quality of your home and health. Water damage can also weaken the foundations and walls of your home, meaning this needs to be dealt with quickly.
- Moisture Evaporating from the Ground. When homes are built with crawl spaces, most builders neglect to cover the ground, meaning that the crawl space is covered with dirt. Dirt has moisture and as the moisture evaporates, it will increase the humidity in your crawl space. To prevent moisture from evaporating from the ground, the easiest solution is to cover it up with a vapor barrier during crawl space encapsulation.
- Outdoor Air Coming in through the Crawl Space Vents. When you bring outdoor air into the crawl space, the relative humidity can increase. Cool air cannot hold as much moisture as warm air, so the air that enters is now closer to its saturation point, referred to as the dew point. It might be 60% relative humidity outside, relative to a temperature of 90 degrees Fahrenheit, but when that air enters the crawl space and cools down to 75 degrees Fahrenheit, the relative humidity jumps up to 95%.
Top 3 Reasons You Must Manage Crawl Space Humidity Levels!
Mold problems in your crawl space will affect the indoor air quality of your home because 40% of the air in your home seeps up through the crawl space.
There are three key reasons you need to ensure that humidity levels in your crawl space are monitored and controlled.
- Health. If the moisture content of your crawl space is not monitored, mold and rot will grow in the insulation or on the wooden beams. When the mold grows, it releases mycotoxins that can seep through the floorboards of your home, which in turn can cause sickness.
- Damaged Subfloor. Moisture accumulation in your crawl space not only affects the air quality of your home, it can also seep through the ceiling of the crawl space and damage your sub-floor. When this occurs, it will begin to warp and eventually need to repaired or replaced.
- Compromised Foundation. Moisture problems can also impact the foundation of your home. The wooden beams that hold up your home’s structure can be damaged by consistent exposure to high levels of moisture, condensation, or humidity.
Having unconditioned air below your living spaces makes your home harder to heat and cool and also provides the perfect damp setting for mold spores to breed which can cause health issues and impact the structural integrity of your home.
With this in mind, it is important to understand that simply ventilating your crawl space is no longer a valid solution to trying to control moisture and humidity.
Rather, since your crawl space can affect the indoor air of your home, it is clear that it needs to be treated almost as a living space of your home.
In short, areas that are in contact with your living space affect your living space.
If you are concerned that your crawl space has humidity or mold concerns that could be impacting your indoor air and health, Valor Mold can help you.
10 Steps To A Mold and Moisture Free Crawl Space!
We can help you dry out the dampest crawl spaces and turn them into drier, healthier foundations for your home that aren’t breeding grounds for mold spores.
Our crawl space solution is different then our competitors because we follow this 10 step procedure:
- Step 1: We level the dirt floor.
- Step 2: We seal off the crawl space vents with plastic covers specifically made for this purpose.
- Step 3: If your crawl space has ground water problems, we’ll make sure the ground slopes where we want the water to go, meaning we may have to physically re-slope the ground using picks and shovels (highly labor intensive, but worth it). Then we’ll dig a hole at the lowest point, put in an air-tight plastic liner and install the best sump pumps made by Zoeller.
- Step 4: Using expanding foam, we seal up the hundreds of small gaps that, unsealed, form a huge air leak. This one step differentiates Valor Mold from most of our competitors, who fail to implement this step because it’s dirty, labor intensive, and very uncomfortable work.
- Step 5: We install special insulation on the walls that is custom-made for crawl spaces.
- Step 6: We install reinforced 12 mil plastic to the walls with special screws, leaving a gap at the top to facilitate yearly termite inspections.
- Step 7: To allow water to drain easily towards the sump pump, we laying dimple board on the dirt floor.
- Step 8: We install a special reinforced 20 mil plastic over the dimple board. Both the dimple board and plastic are held in place with spikes driven into the ground.
- Step 9: We create one continuous moisture barrier in your crawl space using special tape to seal the plastic on the floor to the plastic on the walls.
- Step 10: The first nine steps should keep most of the moisture out of your crawl space. To ensure your crawl space remains dry, we also recommend the installation of a custom dehumidifier made for crawl spaces.
Got Crawl Space Questions?
If you are concerned that you may have mold or humidity concerns in your crawl space, call or text Valor Mold, 571-210-2040 or send us an e-mail. We look forward to serving you! 🙂
Is My Crawl Space Contaminating My Indoor Air Infographic Summary?
— Valor Mold (@ValorMold) July 27, 2016