Last Updated on May 23, 2024

It’s always important to make your home more energy efficient. One of the best ways to do this is by encapsulating your crawl space. 

Crawl spaces are notoriously damp and cold places that can lead to serious structural issues if not properly insulated. However, when encapsulated they can become a valuable asset in helping you sell your home or lease it out at a higher value because they improve the energy efficiency of your home while also lowering utility bills. 

What is a Crawl Space?

A crawl space is a sub-level of a building, usually below ground level. It is enclosed and has no windows or natural light. The purpose of a crawl space is to provide additional living space for the home, but it can also serve as storage space. In some cases, it can also be used as an entrance to the basement.

A crawl space is typically enclosed by walls and/or a ceiling made out of plywood. There are also instances where the walls and ceilings are made out of cement blocks or brick and mortar.

In some cases, there can be more than one level of crawl spaces within a home, depending on how far below ground level they are located. 

Problem with Crawl Spaces

The problem with crawl spaces is that they can be very damp and humid environments. A reason for this is that the soil around your home’s foundation is often moist from rain or snow melt. 

Any moisture in this soil will naturally be drawn into your crawl space through cracks in your foundation, and it will then build up inside the walls and under your house’s floor joists.

If this moisture remains unchecked, it can cause serious problems with your home’s structure over time and health concerns associated with having too much humidity in a crawl space area. 

What is Crawl Space Encapsulation?

What is Crawl Space EncapsulationEncapsulation is a process that involves sealing up your crawl space with a vapor barrier and installing vents to let fresh air into the crawl space while keeping out moisture and pests. The vents can be operated manually or automatically by a fan system. A properly installed encapsulation will keep your home dry and healthy without having to worry about mold or mildew forming in your crawl space. It will also prevent rodents and insects from getting into your house. More importantly, it will reduce the risk of carbon monoxide poisoning.

Benefits of Crawl Space Encapsulation

Encapsulating a crawl space is, in many cases, one of the most effective ways to increase the value of your home. Here are just some of the benefits.

Benefits of Crawl Space EncapsulationBetter Air Quality 

Encapsulating a crawl space can help keep dust and other contaminants out of your home, which can improve air quality.

Reduced Water Damage 

A crawl space that is properly encapsulated will prevent water from getting into your home’s foundation. This can help protect against flooding and other types of water damage to your house.

Lower Energy Costs 

By keeping your home’s crawl space well insulated, you can reduce the amount of energy needed to heat and cool it. This will help lower your monthly utility bills.

Reduced Mold Growth 

Encapsulation can help prevent water from getting into your basement, which reduces the chances of mold growth and its health problems.

Improved Property Value 

Encapsulation can help improve the value of your home. By making it more energy efficient and protecting against water damage, a longer-lasting home could be worth more money when it comes time to sell.

The Typical Step-by-Step Crawl Space Encapsulation Process

When you’re deciding whether to encapsulate your crawl space, it’s important to know the typical steps involved so you can plan ahead. That way, it’ll be easier for you to manage the encapsulation process.

1. Assess Your Crawl Space

Before beginning any encapsulation process, assessing the current state of your crawl space is crucial. Start by checking for any signs of moisture buildup, such as water stains, mold growth, or a musty smell. Use a hygrometer to measure the humidity level; ideally, it should be below 50% to prevent mold growth. Examine the structural integrity of the floor joists and foundation walls for any signs of damage or decay. This initial assessment will guide your encapsulation strategy.

2. Preparation for Encapsulation

Clear the crawl space of any debris, old insulation, or stored materials that might obstruct the encapsulation process. Repair any structural damages found during the assessment. This may include patching holes in the foundation, fixing broken vents, or treating wood rot. Ensuring the space is clean and structurally sound is essential for an effective encapsulation.

3. Material Selection

Choosing the right materials is critical for effective encapsulation:

  • Vapor Barriers: These are essential to prevent moisture from seeping into the crawl space. High-density polyethylene sheets are a popular choice due to their durability and moisture resistance.
  • Insulation: Foam board insulation is commonly used on the walls of crawl spaces because it is less susceptible to moisture damage than fiberglass. Consider the climate of your area; in colder regions, thicker insulation may be necessary.
  • Sealants: Use a high-quality, waterproof sealant to cover any joints, gaps, or seams in the vapor barrier and insulation.

4. Installation

Begin by laying the vapor barrier on the floor and up the foundation walls, overlapping edges by at least 12 inches to ensure comprehensive coverage. Secure it with a waterproof tape. Next, install the insulation on the walls, ensuring it extends all the way to the sill plate. Seal all potential air leaks with the waterproof sealant, especially around entry points for electrical wires and plumbing. If the crawl space has vents, consider sealing them as part of the encapsulation process to maintain a controlled environment.

Economic Analysis and How Crawl Space Encapsulation Increases Property Value

Of course, when you’re deciding whether you should encapsulate your crawl space, you’ll want to weigh the costs and the benefits. More importantly, you’ll want to consider whether it’ll lead to cost savings and an increase in property value.

Costs vs. Benefits

The investment required to encapsulate a crawl space varies based on several factors including the space’s dimensions, material choices, and whether the work is performed by professionals or as a DIY project. Homeowners might expect to spend anywhere from $3,000 to $30,000. Keep in mind, the price will vary depending on the size of your home and the materials used.

Now, despite this initial outlay, the benefits accrued over time are significant, delivering substantial long-term value.

  • Energy Savings: Encapsulation typically leads to a more consistent indoor temperature by minimizing the influx of external air. This thermal stability reduces the demand on heating and cooling systems, leading to an energy cost reduction of up to 20%. Over time, these savings can significantly offset the initial cost of encapsulation.
  • Increased Property Value: Properties featuring encapsulated crawl spaces often attract more interest from prospective buyers. These spaces are perceived as well-maintained and healthier living environments, potentially increasing a home’s market value by 10% or more. This appreciation is particularly notable in regions where buyers are cognizant of energy efficiency and home maintenance.
  • Enhanced Living Conditions and Reduced Maintenance Costs: Encapsulating a crawl space helps prevent issues like mold growth and pest infestations, which contribute to poor indoor air quality and can lead to significant health problems. By addressing these issues, encapsulation enhances living conditions and reduces the need for costly repairs and maintenance related to moisture and pest damage.

Return on Investment (ROI)

The return on investment for crawl space encapsulation is compelling. Most homeowners see a return within five to seven years thanks to the reduced costs associated with heating, cooling, and maintaining their homes. This ROI is further enhanced by the potential increase in property value—homes with encapsulated crawl spaces tend to sell at a premium compared to those without.

Moreover, the improved energy efficiency and property condition contribute to a stronger marketability when selling the home. Real estate listings that highlight energy-efficient upgrades and low maintenance costs attract a broader pool of potential buyers, thereby increasing the likelihood of a favorable sale.

How to know which material to use

The type of material used for encapsulation depends on several factors including…


The larger the crawl space is, the more difficult it will be to seal.


Spray foam insulation costs more than rigid foam board insulation but less than plastic sheeting.


If you live in an area where there is a lot of rain or snowfall then plastic sheeting may be the best choice.


An unfinished or vented crawl space will require different types of material than a sealed crawl space.

Comfort Level

Some people don’t want to deal with the mess associated with spray foam insulation while others don’t mind it at all.

The different types of materials that you can use for encapsulation purposes include…

Plastic Sheeting 

This works well for smaller crawl spaces because it’s easy to install and remove when needed.


Insulating your crawl space provides added protection against moisture build-up since insulation helps keep heat inside your home instead of allowing

Polyethylene Sheeting

A thin plastic sheet commonly used to temporarily cover exposed dirt floors during construction projects. It’s also used as a permanent covering for crawl spaces where moisture control isn’t critical. It comes in different thicknesses and colors. Some brands include an antifungal agent that keeps mold from forming beneath it.

Polyurethane Foam Insulation

Another option for encapsulating a crawl space. It’s made from polyurethane resin and air expanders that produce bubbles in the foam when it cures. The bubbles act like thousands of tiny balloons. They trap air inside them, which prevents heat loss through convection currents and helps maintain a consistent temperature throughout.

Vapor barriers

Used in crawl spaces to keep moisture out of the living space above. This is often an alternative to plastic sheeting because it’s more aesthetically pleasing than regular plastic sheeting would be in most homes. They work by blocking the flow of water vapor through tiny holes in the subflooring. The disadvantage of vapor barriers is that they must be installed over an impervious subflooring material such as concrete or plywood, and they can only be cut or punctured by sharp objects. Also, it tends to wear out faster than plastic sheeting does so it’s not as durable as some other types of encapsulation methods available on the market today.

How does it work?

The encapsulation process begins with the identification of any moisture issues that are present in your crawl space. 

Once problems are identified, they should be addressed by clearing out all items you don’t need in your crawl space. This includes items such as old furniture or even dirt and rocks that may have fallen into the crawl space during work on your foundation.

Remove all old insulation from the walls and floor of your crawl space, as well as any moisture barriers that have been installed previously. This will allow you to insulate properly in these areas going forward and make sure that moisture doesn’t get trapped inside your walls or floor if there is any water leakage from above ground.

Install new insulation along with vapor barriers on top of each other if possible so that there is no chance of any moisture or humidity getting through them into the concrete or wood below them. You also want insulation that is resistant to mold growth so that it doesn’t become a breeding ground for mold spores that can cause respiratory problems.

If you want to protect against water intrusion at this point, it is recommended to install a secondary layer of plywood or OSB (oriented strand board) over top of your insulation.

If you have access to the crawl space above ground, then use vapor barriers on top of each other so that they cannot be penetrated by water in any way.

Install a dehumidifier in your crawl space if possible so that it can help remove moisture from the air before it gets trapped inside your walls or floor.

Install a vent fan in your crawl space if possible so that it can help remove moisture from the air before it gets trapped inside your walls or floor.

Use a crawl space sealer to create an airtight barrier between the ground and your home’s structure.

What does it cost?

Encapsulating a crawlspace is an investment in your home. The cost will depend on the size of your crawlspace, but it’s comparable to other popular home improvements such as adding insulation or replacing windows. There are two ways to approach encapsulation. 

You can do it yourself or hire a professional to help you out. The best thing to do is check your budget to see what you can afford.

Final Thoughts on Crawl Space Encapsulation

Creating an ideal living space is vital in making any home more desirable to potential buyers or renters. Encapsulating your crawl space is a worthy investment. It will not only give your home curb appeal and increase its value but also provide you with valuable peace of mind that your crawl space is no longer a potential source of structural damage and future plumbing issues.

It’s highly recommended to encapsulate your crawl space if you’re selling your house or want to lease out a rental. It’s an easy job that pays off in the long run. Don’t let your crawls pace keep you from reaching your property value goals. 

To learn other ways how to increase the value of your home without breaking the bank head over to our article on renovating a house under 50K.


Why is it important to encapsulate a crawl space?

Encapsulating a crawl space is essential as it effectively transforms a potentially harmful area under your home into a stable, controlled environment. This process involves installing a vapor barrier that covers the ground and walls, effectively blocking moisture penetration from the earth and exterior environment. The benefits are multifaceted:

  • Moisture Control: By preventing moisture ingress, encapsulation helps avoid the conditions that lead to mold growth and wood rot, both of which can undermine structural integrity and cause expensive damages.
  • Improved Air Quality: A dry and well-maintained crawl space means fewer mold spores and less mildew, which significantly improves the overall air quality inside your home. This is particularly beneficial for residents with allergies or respiratory issues.
  • Energy Efficiency: Encapsulation minimizes the entry of hot or cold air into your home, stabilizing indoor temperatures. This reduces the workload on your HVAC system, leading to lower energy bills and a reduced carbon footprint.
  • Pest Prevention: A sealed crawl space deters pests such as rodents and insects, which are attracted to damp areas and can cause additional damage or lead to health concerns.

What is the difference between encapsulated and sealed crawl spaces?

Understanding the distinction between these two terms is key to choosing the right approach for your home:

  • Encapsulation: This comprehensive method involves covering all crawl space surfaces (floors, walls, and sometimes ceilings) with a thick, durable vapor barrier. The space is often conditioned with HVAC ducting or a dehumidifier to regulate air quality and moisture levels. Encapsulation is recommended for maximum protection against moisture and its associated problems.
  • Sealing: Sealing generally refers to the practice of covering crawl space vents to block external air flow. This method can be effective in preventing some moisture issues but does not offer the same level of protection as encapsulation. Sealed spaces may still be susceptible to internal moisture from the ground and walls unless additional steps are taken to install a vapor barrier.

Can I encapsulate my crawl space myself?

While DIY encapsulation is achievable, it requires a significant investment in time, effort, and attention to detail:

  • Measurement and Material Preparation: You must carefully measure your crawl space and cut the vapor barrier material accurately to ensure it fits perfectly. This includes not just the floor area, but also the walls and possibly the ceiling.
  • Installation: Proper installation involves not just laying down the barrier but ensuring every seam is overlapped and sealed with special tape or sealants. You must also properly secure the barrier to the walls and floor to prevent it from coming loose.
  • Additional Equipment: Depending on your crawl space conditions, you may need to install a dehumidifier or sump pump to manage the moisture levels effectively. This equipment requires additional setup and maintenance.
  • Potential for Error: Improper installation can lead to gaps or leaks in the barrier, rendering it ineffective and potentially leading to greater moisture issues than before.

Is it better to encapsulate or ventilate a crawl space?

The choice between encapsulating or ventilating a crawl space hinges on various factors, notably your geographical climate and specific home conditions:

  • Ventilation: In arid climates, ventilating a crawl space can help dissipate excess heat and maintain dry conditions. However, in humid regions, ventilation may introduce more moisture into the crawl space, potentially leading to condensation and moisture-related problems.
  • Encapsulation: Encapsulation is generally recommended regardless of climate because it controls the environment within the crawl space by sealing off external air and moisture. This method involves installing a heavy-duty vapor barrier that covers the ground and walls, and often conditioning the space with a dehumidifier or HVAC system to manage the air quality and moisture levels.

While ventilation might be suitable in less humid, cooler climates, encapsulation provides a more comprehensive and long-term solution for moisture control, making it the preferred method in most scenarios.

How long does crawl space encapsulation last?

With high-quality materials and installation, along with consistent maintenance, encapsulation can effectively last for 20 years or more.

When done correctly, crawl space encapsulation is a durable solution and can last for decades:

  • Material Quality: The longevity of the encapsulation depends significantly on the quality of the vapor barrier used. High-density, puncture-resistant barriers are ideal.
  • Installation Quality: Proper installation is crucial. This includes ensuring complete coverage, correctly overlapping and sealing seams, and securely attaching the barrier to foundation walls.
  • Maintenance: Regular maintenance can help prolong the lifespan of the encapsulation. This involves inspecting the crawl space annually for any signs of barrier compromise, such as tears or water leakage, and addressing these issues promptly.

Can crawl space encapsulation prevent mold, mildew, and pests?

Encapsulation significantly reduces the likelihood of mold and mildew by eliminating the moist conditions necessary for their growth. Furthermore:

  • Pest Prevention: The barrier also helps deter pests such as termites, ants, rodents, and other insects by removing moisture and sealing potential entry points. This is crucial as pests not only cause damage but can also carry diseases.
  • Mold and Mildew Resistance: The reduction in humidity and the presence of a dehumidifying system, if used, help maintain a dry environment that is not conducive to mold and mildew development.

Can crawl space encapsulation protect a home’s foundation and structure?

Absolutely. Encapsulation plays a critical role in safeguarding the structural integrity of a home:

  • Moisture Management: By blocking ground moisture, encapsulation helps prevent the wooden elements of a structure from rotting and the metal components from corroding.
  • Foundation Protection: It also protects the foundation from water damage, which can lead to serious structural issues such as cracks and settling.
  • Overall Stability: Keeping the crawl space dry ensures that the foundation remains strong and stable, which is essential for the long-term durability of the house.

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