What Is Crawl Space Encapsulation?

When was the last time you checked on your home’s crawl space? 

Many homeowners often overlook the importance of their home’s crawl space. They’ll forget to check it until there’s a problem.

Crawl spaces without encapsulation are susceptible to moisture damage, mold, and pest infestations, to name a few problems.

The solution is to encapsulate your crawl space. But what is crawl space encapsulation? 

Here’s everything you need to know about crawl space encapsulation and how it can benefit your home.

What Is Crawl Space Encapsulation?

A crawl space is an area underneath your home that’s similar to a basement. The difference is a crawl space has outside ventilation. 

Unlike a basement, most crawlspaces vary in height from two feet to around standing height. They may consist of a concrete or a dirt floor. 

Crawl spaces offer convenience and affordability during the building stages of a house. During the building process, the crawl space negates the need for a level concrete slab. Crawl spaces also offer a space to install your HVAC equipment.

The problem with a crawl space is the open vents can allow moisture and pests to enter your home.

This is where crawl space encapsulation comes in handy.

If this is a new concept, you’re probably wondering, “what does it mean to encapsulate a crawl space?”

Crawl space encapsulation is a process of lining your crawl space with heavy-duty polyethylene. The polyethylene barrier covers and seals the floors, walls, and, in some cases, the ceiling of your crawl space. 

This barrier is similar to the lining you’ll find in some home swimming pools. Heavy-duty sealing tape seals and connects the barrier pieces.

By encapsulating your crawl space, you’ll reduce damage from moisture and prevent unwanted pests from entering your home. Some crawl space professionals will recommend adding a dehumidifier to keep moisture levels low.

Who Needs to Encapsulate Their Crawl Space?

Anyone with an open or aging crawl space can benefit from adding crawl space encapsulation. Here are a few of the most common reasons homeowners will invest in encapsulating their crawl space:

  • Prevent water damage
  • Prevent the growth and dangers of mold
  • Prevent the growth and smell of mildew
  • Lower home heating and cooling costs
  • Prevent “sweaty” windows
  • Prevent damage to the foundation
  • Eliminate the risk of pest infestations

Adding crawl space encapsulation will improve the air quality in your home while improving healthy living conditions. Encapsulation will improve the structural integrity of your foundation. It does this by preventing water from building up along the foundation of your home.

You can enjoy hardwood and tile floors that are comfortable to walk on all year. Encapsulation adds a layer of insulation that keeps your floors warmer during the winter months.

Finally, encapsulating your crawl space will boost the value of your home. It offers many great benefits by making your home safer and more comfortable to live in.

Crawl Space Encapsulation Materials

Before you begin, you should note there are different types of crawl space encapsulation materials available.

The most popular encapsulation material is the heavy-duty plastic mentioned earlier. This barrier comes in a variety of thicknesses, ranging from 6-mil to 20-mil.

The most durable and effective option is the 20-mil option. Your crawl space contractor will recommend a tear-resistant and anti-microbial barrier finish. This will prevent mold and mildew from growing while ensuring the barrier resists the most wear.

Other materials include insulation, which also comes in a variety of types. The most common types of insulation include:

  • Fiberglass batt insulation
  • Closed-cell spray foam
  • Open-cell spray foam
  • Rigid foam insulation 


A professional crawl space contractor can help you find the right type of insulation for your crawl space. To save money, they recommend insulating only the crawl space ceiling and floor joists, rather than the entire crawl space.

The final materials needed include sealing tape, fasteners, and drainage systems. Humidifiers are a great recommendation to prevent moisture buildup after you encapsulate your crawl space. 

How Do You Encapsulate a Crawl Space?

The next part in learning what is crawl space encapsulation is understanding the installation process.

Most crawl space contractors will follow a similar process when encapsulating your crawl space. They’ll start by repairing and preparing your crawl space before installing the vapor barrier.

  1. The first step is to have a contractor visit and assess the current state of your crawl space. They’ll be able to make recommendations on the best type of encapsulation and any other required needs.

  2. After determining the best crawl space solution, the contractor will remove old insulation, fix any issues, and eliminate any pests.

  3. Before they lay the polyethylene barrier, crawl space professionals will add a layer of spray-on insulation. This insulation will seal vents, holes, and gaps around air ducts and pipes.

  4. After sealing everything, the crawl space encapsulation professionals will start applying the heavy-duty vapor barrier. They’ll attach this on the walls and floor (sometimes the ceiling) to encapsulate and seal the crawl space.

  5. A crawl space professional will use sealing tape and fasteners to attach and seal the barrier in place. The barrier will wrap and seal around pillars and piers in your crawl space.

  6. Once everything is in place, they may recommend adding a dehumidifier. The dehumidifier will keep moisture levels below 50% to keep your crawl space at recommended moisture levels.


Depending on your unique crawl space needs, the entire process can take anywhere from one day to a week. If, for example, your crawl space is in good condition, you can expect the process to take one to days.

What Is the Average Cost of Crawl Space Encapsulation?

The cost to encapsulate your crawl space will ultimately depend on the condition and size of your crawl space.

On average, you can expect to pay anywhere from $5,000 to over $10,000 for professional crawl space encapsulation services.

The quality of materials, size of your crawl space, and labor will affect the cost of crawl space encapsulation.

Different contractors will use different levels of materials. Contractors using high-quality materials will have higher costs than those using low-quality materials. 

Other items will influence the cost of encapsulation. These include the number of barrier layers and items such as sump pumps and dehumidifiers. Each extra feature will cause material and labor costs to rise. 

You can get the most accurate cost by requesting a quote from your contractor.

Crawl Space Encapsulation Pros and Cons

Investing in crawl space encapsulation in your home is never a bad investment. Encapsulation will always boost the value of your house while making it a safer and more pleasant place to live.


Crawl space encapsulation offers many valuable benefits. Here are a few reasons why it’s worth the investment.

Prevent Moisture

Moisture that seeps into your crawl space will lead to many problems. When left unchecked, moisture can compromise the structural integrity of the joists, beams, and foundation of your home.

Moisture will cause your wooden floor joists and beams to expand and warp over time. This moisture will cause the wood to rot as fungus, mold, and mildew start to grow. You will need to replace any features affected by wood rot, which can be an expensive and time-consuming process. 

As moisture enters your crawl space, it can cause the concrete of your foundation to shift and crack. 

Pair a dehumidifier to keep moisture levels low and prevent these problems. 

Prevent Mold and Mildew

Unconditioned crawl spaces harbor moisture. As this moisture continues to build up, mold, mildew, and fungus will start to grow.

Mildew causes a foul odor that can make its way into your home. Mold and fungus are worse, as they will affect the air quality of your home and can cause serious health problems.

Crawl space encapsulation will prevent mold, mildew, and fungus from growing in your home.


There’s no doubt the pros of crawl space encapsulation outweigh the cons. Here are few downsides of encapsulation you should be aware of.

Upfront Cost

Crawl space encapsulation is an investment. As mentioned, the upfront costs start at around $5,000. 

This cost, however, will save you money on expensive repairs to your crawl space. 


After you’ve added an encapsulation to your crawl space, it will require some maintenance to ensure it’s working properly.

You can perform some maintenance checks yourself, but it’s always best to have a professional inspect it for you.

HVAC Upgrades

Crawl space encapsulation will limit some of the airflow in your home and crawl space. This may prevent sufficient oxygen and airflow for a combustion-based furnace. 

In this case, you will need to update your HVAC system to ensure it’s safe and efficient to run in an encapsulated crawl space.

Save Your Home with Crawl Space Encapsulation

What is crawl space encapsulation?

This is the question many new homeowners ask. Crawl space encapsulation is a process of sealing your crawl space to make your home more energy-efficient and a safer place to live.

Do you want to enjoy the benefits of crawl space encapsulation? Request an estimate today! We’re happy to help you with any of your crawl space encapsulation needs.


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