​Your Guide to Crawl Space Encapsulation

Crawl spaces, found in approximately 20% of all newly constructed buildings in the United States, serve vital purposes. They house essential systems, such as HVAC units, electrical wiring, plumbing, gas lines, and irrigation networks. 

Despite their importance, open-vented crawl spaces often face moisture-related problems, including mold growth. These issues reduce the efficiency and durability of HVAC systems and can result in costly repairs due to water damage. 

To address these challenges, experts recommend encapsulation. This preventative measure helps maintain a dry and stable floor system by significantly reducing humidity.

In this article, we will guide you through the process, benefits, and essential considerations for successful crawl space encapsulation. 

What Is Crawl Space Encapsulation? 

A crawl space is a versatile area in the attic below the rafters or as a hidden section near the foundation on the lower level of a building. Unlike a basement, it features outside ventilation and mostly ranges from two feet to around standing height. Its floor may consist of concrete, plywood, or even dirt. 

This space is often used for storage, providing an alternative to a level concrete slab. Its floors and walls are usually lined with six-mil polyethylene to enhance functionality, which provides a high R-value. This lining effectively blocks moisture, vapor, and pests, improving the crawl space’s overall utility. 

A properly sealed crawl space door completes the encapsulation process. It protects the area while allowing convenient access for maintenance and repairs, making it an essential feature of a well-maintained crawl space. 

Why Do You Need to Encapsulate the Crawl Space? 

• Enhances Air Quality: Crawl space encapsulation improves clean air circulation throughout commercial buildings. When left unsealed, a crawl space can become a breeding ground for mold, negatively impacting air quality. 
• Discourages Pests: Termites and other insects rely on moisture to survive. Encapsulation reduces moisture, preventing pests such as termites from settling in. Professional encapsulation addresses crawl space needs, helping to prevent insect infestations, significant damage, and unnecessary hassle. 
• Prevents Structural Damage: Managing moisture accumulation in the crawl space is essential for maintaining the long-term stability of a building’s foundation. Drain pipes direct water from the foundation, making the crawl space dry. Encapsulation prevents moisture retention, ensuring the foundation remains stable. 
• Stops Mold and Mildew Problems: Encapsulation eliminates moisture issues resulting in mold formation, preventing musty, wet odors from spreading through heating and cooling systems. 
• Keeps Floors Comfortable: Hardwood and tile floors feel more comfortable and safer to walk on with crawl space encapsulation, particularly during winter. Additionally, encapsulation helps prevent buildings from feeling damp and humid during hot summer months. 
• Improves Energy Utilization: Encapsulating a crawl space reduces strain on heating or cooling systems, lowering energy bills. Energy savings quickly offset the initial cost of encapsulation. 

How Much Does Crawl Space Encapsulation Cost? 

Crawl space encapsulation improves the longevity of buildings, particularly in humid climates. It helps keep the floor system dry by reducing humidity. 

According to BobVila.com, the costs range from $1,500 to $15,000, with an average of $5,500. 

Steps to Crawl Space Encapsulation 

The following steps outline how to encapsulate a crawl space: 

1. Clean and Seal

   The first step in encapsulation is to clean the crawl space thoroughly. Remove mold or other harmful substances to create a safe working environment. Next, seal open seams between floor tiles or replace them if necessary. Address any cracks in the foundation by consulting a professional before proceeding. Ensure the crawl space door fits snugly, filling any cracks or gaps. Don’t forget to check for gas leaks from the furnace or water heater to prevent backdraft. Finally, inspect and repair structural elements, replace any rotten wood in the flooring or subflooring, and check the joists and rafters for damage. 

2. Create Proper Airflow

   Once the space is clean and sealed, focus on improving ventilation. Proper airflow is essential for keeping the crawl space dry and free from excess humidity. Seal gaps in the floor and install vent covers or insulated doors where necessary. This step ensures fresh air can circulate, reducing the chances of moisture buildup. 

3. Check the Drainage System

   After addressing airflow, turn your attention to drainage. Proper drainage is necessary to prevent water from seeping into the crawl space. Water leaking through foundation walls is a sign of hydrostatic pressure, which can lead to cracks or bowing walls. Installing a drainage system relieves this pressure, protecting the structural stability of the building. Skipping this step could result in significant damage and potential collapse. 

4. Choose the Right Insulation

   With drainage in place, it’s time to add insulation. While fiberglass is a common choice, it absorbs moisture and can encourage mold growth. Spray foam insulation, on the other hand, resists water and is environmentally friendly. It also helps regulate temperatures and reduce energy costs. According to the U.S. Department of Energy, the savings from proper insulation often pay for the investment within a few years. 

5. Remove the Old Moisture Barrier

   Remove the old one before installing a new moisture barrier to create a clean foundation. Leveling the area to ensure a smooth surface makes the installation process easier and more effective. 

6. Install the New Moisture Barrier

   install the vapor barrier by wrapping it around piers and carefully cutting around obstacles such as plumbing or electrical wiring. Secure the barrier with waterproof tape to create a snug fit, and ensure it covers the entire crawl space. Fold corners inward for a clean appearance and overlap seams by a few inches for added protection. 

7. Dehumidify the Crawl Space

   With the moisture barrier in place, it’s time to dry out the crawl space. Installing a dehumidifier is the most effective way to keep moisture levels low year-round. Consider using a humidity monitor to track moisture levels and evaluate the effectiveness of the encapsulation. 

8. Do a Final Inspection

   Finally, a thorough inspection ensures the encapsulation process is complete. Measure and record moisture levels or create a regular maintenance schedule to check the dehumidifier and ensure everything remains in optimal condition. 

To Sum Up 

Crawl space encapsulation is a practical solution to enhance air quality, minimize moisture and pest-related damage, and strengthen the structural stability of a building. It also improves energy efficiency and adds insulation, offering lasting benefits for any structure. 

To make it happen, upgrading to insulated or fire-rated crawl space doors and panels is an essential step. Access Doors and Panels provide secure and convenient access for maintenance while ensuring the encapsulation remains effective by preventing moisture and drafts.

Request a quote to learn more about our durable products. For expert guidance, call us at (800) 609-2917. Our knowledgeable product experts are ready to help you explore options tailored to specific needs, delivering the best results for a well-maintained crawl space.