How To Get Rid Of Musty Smells In A Crawl Space

If you've found this article, you or someone you know has a crawl space with a terrible odor. The smell may overwhelm you when you walk by or open the crawl space door. Or, you may have realized that the musty smell is actually seeping into the living space of the home. What do you have to do to eliminate these awful odors?

South Central Services has insulated hundreds of homes with spray foam. One of our most popular services is crawl space encapsulation, which solves all sorts of crawl space problems. Musty crawl space odors are a common problem. Today, we'll explain where that smell is coming from and how to stop it from returning.

By the end of this article, you will know:

• Why crawl spaces smell so musty
• What steps are necessary to eliminate musty odors

What Causes Musty Smells In Crawl Spaces?

Most crawl spaces in southern Pennsylvania are vented. The idea behind vented crawl spaces is that ventilating air will dry out the crawl space, preventing mold and mildew growth.

Unfortunately, no amount of naturally ventilating air can dry out a crawl space. Vented crawl spaces are left wet, dirty, and dingy. This environment is ideal for mold and mildew growth.

In the summer months, hot and humid air is drawn into the cool crawl space. Since cold air cannot hold as much moisture as warm air, some of this humidity condenses. This leads to moisture problems in the crawl space. As air exchanges between your crawl space and living space, warm and humid air can also enter your home.

In the winter months, cold crawl space air is sucked into your home to replace warm conditioned air that escapes through your attic and roof. Any existing mildew or dirt can be pulled into your living space through that cold air.

At best, the musty smell in a crawl space is due to the circulation of dirty air. At worst, that dirty air also contains active mold spores from excess humidity.

The 3 Steps To Eliminating Musty Odors In Crawl Spaces

Several steps must be taken to eliminate the musty smell of a crawl space. Without these steps, your crawl space remains open to humidity and air infiltration. The steps are:

1. Mold treatment
2. Air conditioning
3. Infiltration prevention

Let’s examine each of these in more detail.

Step 1: Treat Any Existing Mold Or Mildew.

Hopefully, there is no mold or mildew in your crawl space. However, the potential presence of mold is something that must be taken seriously. Condensation and excess humidity that infiltrates your crawl space during the summer can activate mold spores. The air in your crawl space needs to be tested for mold.

You can hire a professional to test your crawl space air or purchase a DIY kit. However you go about it, it is vital to determine if there are active mold spores in your crawl space.

If mold or mildew is present, it must be treated.

Step 2: Condition The Crawl Space Air.

After any mold or mildew has been treated, the crawl space air needs to be conditioned. Damp conditions encourage mold growth, so the air needs to be dried out.

Without conditioning in the crawl space, there is no temperature or moisture control. Air will continue to exchange between the crawl space and living space. You want that air to be clean, dry, and temperature regulated.

The crawl space air can be conditioned with an industrial fan or a crawl space dehumidifier.

Step 3: Stop Air Infiltration In The Crawl Space.

Once the air in the crawl space is dry, it needs to stay that way.

Any air infiltration will allow moisture back into the crawl space air. So, the solution to keep the crawl space air conditioned is to stop air infiltration.

Vented crawl spaces allow free air exchange in a crawl space. To stop this random air exchange, a crawl space should be encapsulated. Encapsulation will prevent moisture from coming back into the space.

If air from outside your home cannot infiltrate your crawl space, the crawl space air can stay conditioned. This is good for your energy costs, your home comfort, and your air quality.

If You Don’t Do All 3 Steps, The Musty Smell Will Come Back.

Each of these steps is vital to treating the musty odors in your crawl space. A partial job may temporarily eliminate the smell, but the odor will inevitably return.

What Happens If You Don't Stop The Air From Infiltrating?

Treating any existing mold and drying out the air will temporarily stop the musty smells. However, if you don't stop the air infiltration, these problems will begin again. The air will not stay dry. Once the air is wet and humid again, mold will be able to grow again.

Imagine your home in the summertime. The hot, humid air outside of your home is drawn to your cool crawl space. Despite treating mold and running a dehumidification system, humidity can still enter the space.

It is a similar concept to running your air conditioning with your windows open. Without stopping air infiltration, the musty smell cannot truly be addressed.

What Happens If You Don’t Test For And Treat Existing Mold?

If you dry out the crawl space air and stop infiltration, you will have created a conditioned space. The crawl space will not support future mold growth. However, by skipping the mold testing step, any existing mold would still be present. The musty odor will not leave because a root cause was never resolved.

What Happens If You Don’t Dry Out The Air In Your Crawl Space?

If you treat any existing mold and stop air infiltration, you can create a space that is able to be conditioned. However, not conditioning the air leaves the space open to new mold growth. Additionally, the air will be damp and musty until the air is dried out.

Even though you don’t live in your crawl space, the temperature and quality of its air influences your living space. Once an effort has been made to treat mold and prevent new humidity, the air in your crawl space will still exchange with your home.

It would be similar to leaving a room in your home free from air conditioning in summer and heating during winter. That space will affect the comfort and air quality of the rest of the house.

The Solution For Musty Crawl Space Odors Is Encapsulation.

Crawl space encapsulation is the only method that treats existing mold, conditions crawl space air, and stops future air infiltration. No other crawl space insulation method can solve the root causes of musty odors.

Encapsulation cuts the crawl space off from outside elements and turns it into a conditioned space. An encapsulated crawl space intentionally exchanges air with the living space, because the crawl space air is clean and dry.

No matter the temperature changes in summer and winter, air cannot infiltrate the crawl space. There is no excess humidity in the summer months.

The Bottom Line About Removing Musty Odors In Crawl Spaces

Few things are more frustrating for homeowners than a mysterious unpleasant odor. Many homeowners in our service area have vented crawl spaces with a pervading musty smell. The solution we recommend is encapsulation, which addresses the three root causes of musty odors.

Musty smells in the crawl space can be caused by damp air, active mold spores, or dirty air infiltrating from the ground.

Now that you understand that encapsulation solves crawl space smells, your next step is to:

• Compare vented and encapsulated crawl spaces
• Discover how the encapsulation method works
• Learn whether encapsulation is really right for you