Skip to Main Content

Crawl Space Vents: Why They’re Bad & 3 Easy Steps to Seal Them

crawl space vent

Many homes in North Carolina feature crawl spaces that store HVAC units, pipes, ductwork, and wiring. When crawl space vents are open, these areas are susceptible to moisture and outdoor elements, potentially leading to concerns such as mold growth and structural issues. To address this risk, consider improving your crawl space ventilation.  
Managing moisture infiltration in crawl spaces is a common challenge for homeowners. If you’re determining whether to leave crawl space vents open or closed or learning how to seal them, you’re in the right place.  

This page explores crawl space repair, the risks of open crawl space vents, and how to seal them for optimal protection. 

Should You Leave Crawl Space Vents Open or Closed? 

brown crawl space vent

Closed and sealed crawl space vents are recommended to improve the overall condition of your home. This simple step offers many benefits, like reduced energy consumption and crawl space mold prevention. Creating a healthy living space involves achieving an ideal crawl space environment.  

Choosing whether to leave crawl space vents open or closed while also addressing them is a proactive step you can take in safeguarding your investment. 

How Does Crawl Space Ventilation Work? 

Proper crawl space ventilation is crucial for maintaining a healthy home. It regulates moisture to prevent mold growth, wood rot, and pest infestations. Crawl space ventilation enables passive air exchange and eliminates excess moisture and condensation buildup. 
Closing vents during humid periods also help prevent crawl space humidity. In consistently humid regions, keeping vents closed may be necessary. The effectiveness of ventilation depends on factors such as climate and location, often requiring additional strategies beyond vent operation.  
Inadequate ventilation can lead to significant problems, emphasizing the necessity of sufficient ventilation for a healthy living environment. 

Contact an expert for advice tailored to your home’s needs, especially if you live in a region with extreme weather or have a complicated crawl space setup. 

How to Seal Open Crawl Space Vents 

Regaining control of your crawl space starts with sealing its vents. While you may consider a DIY approach, it’s crucial to understand the complexities involved and consider professional installation for the best results.  

Here’s a simple three-step guide on how to seal crawl space vents: 

1. Assessment 

Before starting the crawl space sealing process, contact an expert to assess the condition of the area and vents. Check for signs of damage, potential entry points for moisture and pests, and existing issues like mold or rot. Identifying these problems is crucial for developing an effective vent-sealing strategy. 

a worker installs insulation in a crawl space

2. Cleaning 

Clean the area around the crawl space vents before sealing. Remove debris like leaves, dirt, and cobwebs, as they can hinder the seal’s effectiveness and contribute to moisture problems. A clean surface ensures proper adherence to sealing materials, creating a more substantial barrier against external elements. 

3. Sealing 

Choose suitable materials specifically designed for crawl space vent sealing—opt for moisture-resistant and durable sealants or insulation. Apply the chosen materials carefully, ensuring complete coverage of the open vents. Proper sealing prevents moisture, pests, and insects from entering, addressing potential problems at their source. 

DIY sealing has practical aspects, but it can be challenging. It cannot guarantee long-term effectiveness or address ventilation issues. Choosing expert inspection and installation ensures complete crawl space protection. Certified experts ensure safety compliance and implement lasting solutions for optimal crawl space conditions. 

a worker seals a crawl space with insulation

Schedule a Free Crawl Space Inspection Today! 

Tar Heel work truck

Addressing open crawl space vents is an essential step toward promoting the safety and health of your home. Sealing open vents creates a healthier and more resilient living space and safeguards your home against potential threats. 

Contact Tar Heel Basement Systems for a free crawl space inspection and estimate. Our team provides tailored crawl space repair and encapsulation solutions to address your home’s needs. We ensure peace of mind and a healthier home environment. 


When the process of sealing a crawl space is done incorrectly, it can lead to moisture issues, resulting in mold and other unhealthy issues. Professional installation ensures adequate ventilation and prevents potential problems.

Waterproofing crawl space vents involves specialized sealants to create a moisture-resistant barrier. Contact a professional who can inspect the area and offer tailored solutions for your home’s space.

Yes, sealing a crawl space is a beneficial step to prevent moisture, pests, and insect intrusion, improving your home’s living conditions. It’s crucial to contact a professional and address open crawl space vents to ensure proper ventilation and avoid potential moisture issues.


Publish Date:

Last Modified Date:

TarHeel Basement Systems Service Map

Our Locations

Fayetteville Location

3400 Walsh Pky, Suite 220
Fayetteville, NC 28311

Greensboro Location

611 Summit Ave, Suite 5
Greensboro, NC 27405

North Raleigh

208 Millbrook Rd. Suite C
Raleigh, NC 27609

Raleigh / Durham / Chapel Hill Location

3333 Air Park Road
Fuquay-Varina, NC 27526

Wilmington Location

2155 Enterprise Dr. NE
Leland, NC 28451

Winston-salem / High Point Location

2910 Griffith Rd
Winston-Salem, NC 27103