Do you have a damp crawl space? Are you wondering whether it needs a ventilation fan? Do crawl space ventilation fans really work as advertised to reduce crawl space moisture? In this post, we’ll explore the question of if crawl space ventilation fans really help improve indoor air quality and determine whether investing in one is worth it.
What Is a Crawl Space Foundation?
A crawl space foundation (also known as a raised foundation) is a type of foundation that elevates a home slightly above ground level. The crawl space is the open area between the bottom of the house and the ground. It is usually between one and three feet high, with just enough room to crawl around in.
Crawl space foundations have been popular for decades, not only because they’re less expensive to build than basement foundations, but also because they provide easy access to plumbing and electrical systems for maintenance and repairs.
While there are many pros to crawl space foundations, they are prone to moisture issues as well, which can lead to structural instability if they are not corrected.
Why You Don’t Want Humidity in Your Crawl Space
Humidity is extremely detrimental to crawl spaces, as it can lead to an array of problems that can threaten the structural integrity of a home and the health of its inhabitants.
Excessive moisture can cause wooden beams to rot, possibly leading to a collapse of the entire crawl space if left unchecked. Moisture can also invite termites and other pests to nest, infesting and weakening the structure further. Humidity can also encourage the growth of mold, a dangerous and toxic substance that is known to cause respiratory issues and allergic reactions. Crawl space mold spores can spread to other areas of your home, causing widespread contamination and illness.
What Are Crawl Space Ventilation Fans, and Do They Really Work?
Crawl space ventilation fans are devices designed to blow outside air into a crawl space to maintain optimal humidity levels and provide adequate airflow.
There are different types of crawl space ventilation fans available on the market, each with its own set of unique features and benefits. Some models are designed to be installed on the foundation walls, while others are mounted on the floor or ceiling. They may be powered by electricity or solar energy, and some even come with advanced features such as built-in moisture sensors and adjustable speed settings.
But do they really work? Do they really prevent moisture from building up in the crawl space? The answer is no.
The Problem With Crawl Space Ventilation Fans
Open crawl space vents and crawl space ventilation fans are commonly believed to help maintain proper airflow and reduce humidity levels in crawl spaces. However, this is far from the truth. In reality, open crawl space vents do more harm than good when regulating humidity levels in the crawl space.
The most significant issue with open vents is that they allow warm, humid outside air to enter into the crawl space, which then condenses on cooler surfaces. This creates a perfect environment for mold and mildew growth, which can in turn pose a serious threat to your family’s health.
As noted above, moisture in the crawl space can also lead to wood decay and structural damage. Moisture is a known enemy of wood and can cause warping, cracking, and rotting over time. In addition, a damp crawl space can encourage insect infestations, such as termites and carpenter ants, that can further weaken the structural integrity of your home.
So, contrary to popular belief, open crawl space vents can do more harm than good if you’re trying to keep the humidity level in the crawl space down.
The Right Way to Control Crawl Space Humidity
If you want to control moisture in the crawl space, then a ventilation fan is not the way to go. A better option is to seal the vents, encapsulate the crawl space, and install a dehumidifier. If excess groundwater is a problem, a drain tile system can also be added.
Seal the Vents
Sealing the vents is a crucial step in moisture control. As noted above, airflow into the crawl space is one of the key factors in moisture buildup.
Encapsulation
Encapsulation involves covering the dirt floor and walls of the crawl space with a thick, vapor-retarding barrier.
Install a dehumidifier
A dehumidifier will extract excess moisture from the air and aid in maintaining a humidity level of 50 percent or less within the crawl space. Homeowners should ensure that the dehumidifier is rated for the size of their crawl space.
Other Things You Can Do to Help Keep Your Crawl Space Dry
Making sure that the ground around the crawl space remains dry is critical. Here are some things you can do to control groundwater around the foundation:
- Regrade your yard – This involves reshaping the soil around the house to ensure water flows away from the foundation. If water accumulates around the foundation, it will eventually find its way into your crawl space.
- Install downspout extensions – Downspouts that are too short will release runoff next to your foundation. Extensions will ensure water gets carried away from the foundation before release.
- Clean gutters regularly – Clogged gutters can cause water to overflow, run down the side of the house, and soak the ground around the foundation.
- Install a drain tile system – A drain tile system is a method of groundwater management that prevents water from accumulating in the ground around the foundation. The system is composed of a perforated drain pipe buried in a trench with gravel surrounding it. This trench is typically placed around the perimeter of the foundation at the footing level. For more information, see our article What Is Drain Tile
If you’re concerned about moisture in your home’s crawl space, contact AMC911 today to schedule a free crawl space inspection and receive an estimate.
