crawl space encapsulation vs vapor barrier

Crawl Space Encapsulation vs Vapor Barrier: Which is Right for You?

Do you own a crawl space? Have you ever considered the difference between crawl space encapsulation vs. vapor barrier?

Crawl space encapsulation is where you seal the entire crawl space of the house using a water vapor barrier that is usually made of heavy-duty polyethylene. Crawl space encapsulation will ensure your crawl space is free of moisture, Pests, bad-quality air, and mold.

A vapor barrier is also known as a moisture barrier. On the other hand, it is a plastic liner that allows you to maintain a clean and dry crawl space for a safer and healthier home.

This article focuses on how the two methods differ, the best option, the pros and cons, and many other areas you need to know before making a choice.

What Is The Difference Between Crawl Space Encapsulation And A Vapor Barrier?

Though these waterproofing methods help control moisture in crawl spaces, they also differ.

For crawl space encapsulation, you need a plastic layer that has a thickness of 12mm to 14 mm to conceal the entire crawl space completely. Vapor barriers do not require such thick layers and therefore do not completely seal the space.

Another difference between the crawl space encapsulation and the vapor barrier is the requirement for a dehumidifier. If you decide to encapsulate your crawl space, it is best to install a dehumidifier to maximize the effectiveness of encapsulation. However, when installing a vapor barrier, a dehumidifier is not essential.

The vapor barrier is much more affordable than encapsulation when considering the cost, mainly because you don’t need any additional devices when installing a vapor barrier. However, for encapsulation, you need a dehumidifier and a sump pump to get the best outcome out of it.

A vapor barrier is also comparatively cheaper with maintenance. Since a dehumidifier and sump pump are required in encapsulation, these devices require maintenance. In contrast, a vapor barrier does not use either device, so no maintenance is required.

What Are The Pros And Cons Of Crawl Space Encapsulation?

Encapsulations are becoming popular today as they offer users an array of benefits.

Let’s see a few of the pros and cons of crawl space encapsulation.


  • It significantly reduces the formation of mold and prevents the rotting of wood
  • It contributes to reducing soaring electricity bills
  • Improves air quality
  • Helps pest control
  • Enhances the value of the house
  • Completely seals all vents and inlets of the crawl space
  • Effectively controls humidity levels
  • Significantly reduces issues caused to the floor of the house due to dampness underneath
  • Helps to increase the durability of ductwork
  • Provides better comfort and safety


  • The process from purchasing to installing is expensive.
  • Maintenance is necessary and expensive.
  • You will have either limited or no access to the crawl space since the walls will be sealed; therefore, it is recommended to have an opening to enable access for frequent inspections and repairs in case of a breakdown.
  • High chance of experiencing bad odors
  • Not suitable to do it yourself as you are dealing with electricals in a dangerous environment

Considering the pros and cons of crawl space encapsulation, there are factors that you need to consider when deciding if this is the best option.

For instance, you need to consider the condition of your crawl space. Usually, the crawl space of a house is a neglected area; therefore, it isn’t easy to expect a crawl space to be maintained or in good condition.

Encapsulation gives a crawl space in poor condition a whole new look. The size of the crawl space and the climate are among the factors you need to consider if choosing encapsulation over a vapor barrier.

What Is The Purpose Of The Vapor Barrier In The Crawl Space?

Those who install vapor barriers in their crawl spaces can enjoy many benefits. A vapor barrier protects the house from water damage, improves personal health, keeps moisture out, etc.

Keeping moisture out is one of the key purposes of a vapor barrier.

Apart from controlling humidity, vapor barriers prevent moisture from soil evaporating and entering the house. It acts as a barrier between the soil and the surface of the house.

Another primary purpose of a vapor barrier is that it helps to protect you from wiring hazards in the crawl space by adding an extra layer of protection between water and electricity.

Vapor barriers also protect HVAC systems or ductwork present in the crawl space from rusting and corroding. It prolongs the longevity of these components as it prevents contact between the components and water.

What Are The Disadvantages Of The Vapor Barrier?

Similar to having pros, the vapor barrier also has a few drawbacks.

A vapor barrier is not durable. Many installation companies use a thin plastic layer around 4 to 6 mil thick, for the convenience of spreading it more easily and to a wider area. However, the recommended thickness is 12 mil or more to ensure durability.

You cannot completely rely on a vapor barrier to eradicate water entering your crawl space. There could be other ways of water entering the crawl space, like pipe leaks, heavy rains, and cracks in the walls, given that it does not completely seal the walls or the columns.

Water from these sources will likely retain within the crawl space and eventually release a bad odor due to foul water.

What Are The Disadvantages Of The Vapor Barrier?

Does The Code In The Crawl Space Require A Vapor Barrier?

Yes. A vapor barrier that fulfills crawl space code requirements is recommended when dealing with breathable air. It is best for the safety and health of the occupants in the house.

There are crawl space code requirements for both ventilated and unventilated spaces. You can get an idea of these requirements from the installation company or the Internet. For instance, according to the IRC (International Residential Code), the requirement is to have a Class 1 vapor retarder for unventilated crawl spaces.

The recommended class of vapor barrier will be the ideal barrier type for the best outcome. Ensure that you choose the suitable vapor retarder wisely and one that meets the IRC requirements.

How To Choose Between Crawl Space Vapor Barrier Vs Encapsulation?

Now it’s time to decide on the best option. The easiest way to choose between crawl space vapor barrier and encapsulation is by considering the pros and cons of the two waterproofing methods. Additionally, you can consider the factors below to ease your decision-making process.

The Size Of Your Crawl Space

If your crawl space is long, you might need more materials to cover the whole length. In that case, it is better to use a vapor barrier as it is relatively cheaper than encapsulation.

Your Budget

As stated before, a crawl space is not compulsory for a house. However, if you already reside in a house with a crawl space, you have no choice but to maintain it.

If you are on a tight budget, it is best to go ahead with a vapor barrier, as the installation and maintenance are more affordable than encapsulation.

Yet, despite your budget, if you still need to go with a method that is durable and worthy of the money, then it is best to consider encapsulation

Condition Of Your Crawl Space

If your crawl space is in average condition and you live in a low-humidity region, the best choice is to select a vapor barrier.

Encapsulation is better suited for high-humidity areas and those crawl spaces with excess moisture.

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