Should Crawl Space Vents Be Open or Closed: What You Need to Know

If you’re like most homeowners, you probably don’t think about your crawl space too often. Since your crawl space is out of sight, it’s easy to be out of your mind, too. But don’t underestimate the importance of this area! Crawl spaces may be small, yet they play a huge role in the overall health and stability of your home.

To protect your home from potential damage, it’s essential to understand your crawl space, and a great place to start is with your crawl space vents.

Why do Crawl Spaces Have Vents?

Keeping a crawl space dry is crucial to avoid problems like mold, mildew, and wood rot. Traditionally, crawl spaces were constructed with vents based on the theory that fresh air circulating through the crawl space would help remove excess moisture and maintain a healthy environment.

However, this is often not the case. In fact, for homeowners in many climates, vented crawl spaces actually contribute to moisture problems. As outside air enters the crawl space, so does moisture. This is problematic, especially during humid weather, because the moisture condenses on cold surfaces, like pipes, foundation walls, and even insulation, leading to mold and mildew growth.

“If you’ve ever asked questions like “when should I open my crawl space vents” or “should crawl space vents be open during the summer,” the answer is no. The very first step in keeping your crawl space dry? Closing your vents!”

-Steve Karlik, Owner & Founder of Blue Umbrella Waterproofing

Is it Bad to Block Crawl Space Vents?

It seems reasonable to expect open crawl space vents to circulate air and mitigate problems like excess moisture, but that usually is not what actually happens. In addition to problems like mold and mildew growth, open crawl space vents can lead to energy loss.

Blocking, or closing crawl space vents helps to prevent moisture accumulation and energy loss. Closed crawl space vents make it much harder for cold or warm air to enter your crawl space. Air that enters your crawl space subsequently enters your living space, so if cold air enters your crawl space in the winter, cold air will also enter your home. The same is true for hot air in the summer. A blocked crawl space vent prevents this, keeping your indoor temperature more consistent, so your HVAC system doesn’t have to work as hard, and you stay more comfortable.

The Risks of Open Crawl Space Vents

When crawl space vents are left open, your home is vulnerable to several issues, some of which include:

The Stack Effect

The air in your crawl space is often cooler than outside air, so when outside air enters through open vents, the humidity level in your crawl space rises. This leads to condensation that can create problems like mold growth and wood rot.

Then, the warm, moist air from the crawl space rises into your home, carrying unwanted dust mites and mold spores, which can affect indoor air quality and cause respiratory problems for you and your family.

Mold Growth

Mold thrives in dark, damp, and humid areas, which makes an open crawl space the perfect breeding ground. According to the New Jersey Department of Health, mold problems are often the result of excessive water. When your crawl space vents are open, moisture enters, giving mold a dark and damp place to grow.

Mold growth is more than a cosmetic issue. As noted by the United States Environmental Protection Agency, mold eats anything that it grows on. When mold grows in your crawl space, it feeds on building materials contained there, which can ultimately lead to structural damage.

In addition to causing damage to your home, mold growth can pose a threat to the health of your family. As air from your crawl space travels upwards into your home, mold spores hitch a ride, too. These unseen mold spores affect the quality of your indoor air and can cause respiratory issues with asthma-like symptoms such as coughing or wheezing.

High Utility Bills

Most homeowners are looking for ways to cut down on utility bills, and closing your crawl space vents can help! In the winter, a closed crawl space vent helps prevent cold air from entering your home, and in the summer, a closed vent helps prevent warmer air from entering.

Because your indoor air temperature remains more consistent, your HVAC system won’t have to work as hard to maintain a comfortable temperature. Lower energy consumption leads to lower utility bills, and a more comfortable indoor environment year-round!

Wet Insulation

When humid air enters your crawl space through open vents, it causes condensation on available surfaces, like your insulation. Wet insulation not only reduces thermal resistance that leads to increased energy consumption, it also can cause other problems like:

• Mold and Mildew Growth: Wet insulation in your crawl space is the perfect environment for mold growth.
• Pest Infestation: Not only does wet insulation make an attractive environment for mold, but it also can attract pests like rodents, insects, and other critters. These pests can cause damage to your home and pose health risks.
• Structural Damage: Prolonged exposure to moisture, like wet insulation, can lead to wood rot. When this happens, the structural integrity of your entire home can be weakened.
• Unpleasant Odors: Wet insulation can produce a musty odor that permeates your entire home, and while that might not threaten your home’s structure or energy costs, strong odors can certainly make for an unpleasant environment.

Wood Rot

Wood rot is a natural process in which wood is exposed to excess moisture, like condensation buildup in your crawl space. Humid air that enters through open crawl space vents increases moisture levels around wooden beams and joists, which leads to wood rot over time. As wood continues to rot and weaken, the entire structural integrity of your home can be compromised leading to costly damage.

How to Dry Your Crawl Space

If you’ve ever asked questions like “when should I open my crawl space vents” or “should crawl space vents be open during the summer,” the answer is no. The very first step in keeping your crawl space dry? Closing your vents! A closed crawl space vent prevents excess moisture accumulation, regulates temperature better, and protects your home against many issues associated with too much moisture.

There are multiple ways to keep your crawl space dry. The most common, and effective, methods of maintaining a dry and efficient crawl space include:

Crawl Space Waterproofing

Crawl space waterproofing is exactly what it sounds like; it’s installing a system designed to remove water from your crawl space. It’s a simple definition, but for it to be effective, it’s best to let an experienced crawl space waterproofing company handle the job.

Proper crawl space waterproofing requires multiple steps, including:

● Removal of Existing Water: Before crawl space waterproofing contractors can begin the process, they first must remove existing water. Additionally, the crawl space area needs to be cleaned, and if there is any mold damage, mold remediation specialists should handle mold removal before waterproofing begins.
● Install Interior French Drains: Interior french drains capture water in the crawl space. If you have a dirt floor in your crawl space, your contractors will dig along the perimeter of the crawl space. For New Jersey homeowners with a concrete floor, crawl space waterproofing experts will jackhammer a perimeter trench. A french drain is then installed and covered with stone.
● Add a Crawl Space Sump Pump: Your contractor will identify a corner of your crawl space perfect for the placement of a sump pump basin. For some larger homes, an additional sump pump basin may be required. With the sump pump basin dug, a sump pump is installed. Water collected in your french drain travels to the sump pump, which will pump water away from your crawl space.
● Place Underground Exterior Discharge Pipe: Water pumped away from your crawl space needs somewhere to go, and that’s where an underground discharge line comes in. An underground discharge line will be buried in your yard, and will direct water to the street or a minimum of 15 feet from your home.

Crawl Space Encapsulation

Crawl space encapsulation is the process of sealing your crawl space. This includes closing crawl space vents, installing vinyl liners, and a sealable crawl space door. While some home improvement projects are simple enough for a DIY approach, crawl space encapsulation is best left to the professionals.

● Clean Your Crawl Space: As with waterproofing, a clean crawl space is required before any work can begin. Any debris, pests, or water must be removed before the start of the encapsulation process.
● Seal All Openings: Any openings to your crawl space are closed, including your crawl space vents. Vent covers seal the openings, and a crawl space entrance door with proper sealing is added to ensure outside air cannot enter your crawl space.
● Add a Vapor Barrier: This step is why hiring seasoned crawl space encapsulation contractors is crucial! Drainage matting will be laid, then covered with a vinyl vapor liner on your crawl space floors and walls. A vapor barrier will be wrapped tightly around any support piers or columns in your crawl space. This vinyl liner prevents moisture from permeating your crawl space, keeping it dry and safe from problems like mold growth and wood rot.
● Put in a Crawl Space Dehumidifier: Your New Jersey home will benefit significantly from adding a crawl space dehumidifier. This dehumidifier cycles air in your crawl space to remove excess moisture and filters dust mites, mold spores, pollen, and other allergens from your air to ensure you have healthy, high-quality indoor air.
● Install a Crawl Space Sump Pump: You are probably familiar with a basement sump pump, and a crawl space sump pump works the same way. Our crawl space encapsulation experts will dig one, or multiple, sump pump basins then install a sump pump in your crawl space. Water collects in the sump pump before being directed away from your property via an underground discharge pipe.
● Build Exterior Underground Discharge: Water pumped out of your sump pump has to go somewhere, and you don’t want it to pool near your crawl space or foundation. An underground discharge pipe will be installed to ensure that water is directed a safe distance away from your property.

Want a more detailed explanation of crawl space encapsulation and how it can benefit your New Jersey home? Here’s a more comprehensive guide to crawl space encapsulation.

Crawl Space Dehumidifier

You know by now how dangerous excess moisture in your crawl space can be. Don’t let your crawl space become a petri dish incubating its own colony of mold, keep it dry with a dehumidifier designed specifically for your crawl space.

You’re probably familiar with dehumidifiers, you might even have some for rooms in your home. However, a crawl space dehumidifier differs from one you can pick up on your weekly grocery run. Crawl space dehumidifiers have two main functions: they keep your crawl space dry and your crawl space air clean.

Crawl space dehumidifiers pull damp air from your crawl space, remove moisture, and then expel dry air. As the air is pulled into the dehumidifier, it is run through a filter that removes much more than moisture. Blue Umbrella installs high-quality AprilAire dehumidifiers, which use a high-grade filter to eliminate dust mites, pollen, dander, bacteria, and other undesirable elements from your air to protect your family from breathing in harmful allergens.

Getting Started With Blue Umbrella Waterproofing

Closing the vents is just the first step in ensuring a dry and healthy crawl space. To ensure your crawl space has superior protection against excess moisture, humidity, and pests, choosing a trusted crawl space waterproofing company is your best bet. With more than 20 years of experience, Blue Umbrella Waterproofing is the New Jersey crawl space encapsulation company to call.

Our highly skilled and expertly trained professionals understand the unique challenges New Jersey homeowners face, like hydrostatic pressure causing excess water to accumulate in basements, and offer proven techniques to keep your home protected against moisture.

Stop ignoring your crawl space! Get in touch with Blue Umbrella Waterproofing today to find out more about our comprehensive crawl space waterproofing and encapsulation services. With a lifetime transferable warranty, you can choose us in confidence knowing that your home is protected for as long as our waterproofing system remains in place. Get started today by filling out one of our forms, or give us a call to speak with a friendly and helpful representative!