Crawl Space Encapsulation 101: A Homeowner's Guide

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Quick. Guess this riddle: It's underneath your house. It's dark, it's cold, it's infested with spiders, and it's...wet?

It's your crawl space! We'll cut to the chase: Dirt crawl spaces are not good for you. They're prone to moisture and humidity which can cause serious structural problems and bad air quality throughout your home. 

If you're asking yourself, how do I fix it?! Then, you're in the right place. The best way to keep moisture out of your crawl space is with crawl space encapsulation. In this blog, we'll go over everything you need to know about crawl space encapsulation to help you decide if it's a good decision for your home. Let's dive in. 

What is a crawl space?

Crawl spaces are usually unfinished, narrow spaces at the lowest level of a house or structure that creates a barrier between the ground and the first floor. And because they're unfinished, they have dirt floors. 

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Why do builders build crawl space foundations?

There are two common reasons why your home might have a crawl space. 

  1. You live in an area that gets a lot of moisture. Either rainfall or near a body of water, like the Pacific Northwest or Florida. Crawl spaces are able to prevent flooding damage by lifting your home off the ground.
  2. The builder that built prioritized their time and money over the future homeowner's safety. Crawl spaces are cheaper and easier to build than other foundation types. For example, you don't have to dig a huge hole as you do with a basement. Because of that, they're not only less expensive to build, but they save the builder time and money

There's another reason why your home might have a crawl space foundation. From 1950 to 1970, there was a housing shortage. After The Great Depression and WWII ended, veterans returned home. They got married and started families. And because there were no new houses being built during those two events, there was a huge demand for houses. So builders needed to build several houses in a short amount of time. What's the easiest and fastest way to build a house? Give it a crawl space foundation. 

Crawl space encapsulation: everything you need to know

Crawl space encapsulation refers to lining your crawl space with a heavy-duty vapor barrier to seal the space off from the outside.

The vapor barrier is a thick, sheet of polyethylene plastic that is placed on the walls and dirt floors of your crawl space.

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Crawl space encapsulation reduces humidity and prevents leaks, pests, and mold from entering your crawl space.

Why should I do crawl space encapsulation?

There are several reasons why you should encapsulate your crawl space. 

  • Humidity and moisture. Dirt floors contribute a lot of water vapor into the crawl space air. Unfortunately, the water vapor is humid and moves upwards into your home. This can increase your energy bills.

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  • Mold and bad air quality. If you have a crawl space with a dirt floor, you are opening up your home to mold. Groundwater will seep and puddle. Those puddles will sit there, creating the perfect environment for mold. Eventually, they'll evaporate into the air. But that air won't stay in the crawl space; it is always flowing so it'll move upward into your home. That's humid air with mold spores in your house that you're breathing in. 
  • Pest infestations. Mice, rats, spiders, and snakes love dark, damp places to hide and breed in. And often, they find places like your crawl space to die in. Because air is always moving, you'll be smelling that throughout your home.
  • Lowers structural integrity. Groundwater and moisture in the crawl space will eventually deteriorate any wood down there. Wooden structural pieces, like joists, will start to rot and not be able to handle the weight of your home. This compromises your home as a safe place to live and will be thousands of dollars in foundation repair. 

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How does crawl space encapsulation work? 

Here’s how we tackle and encapsulate crawl spaces as a crawl space contractor.

Step 1: Inspection

Once you contact a foundation repair contractor, the first thing they're going to do is inspect your crawl space to assess the condition of your crawl space.

Step 2: Direct water away from the home

Some crawl spaces have a lot of groundwater seepage and it can be an issue. To fix this, we suggest installing a sump pump. It's a device that will capture any water and pump it away, before it ever enters your house.

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Install is easy. We dig a 22-inch hole in the lowest spot in your crawl space. Sometimes, we move the soil around so everything is at a downward slope toward the pump. 

Step 3: Seal the house from the dirt floors

This is where we encapsulate. To fix all water vapor issues, we install our thick vapor barrier. It's roughly 20mil thick plastic that is fitted and custom to your crawl space. 

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We install it to the walls, ceilings, and floors by using special tapes, sealants, and attaching fasteners. 

Step 5: It's time to dehumidify

After installing a vapor barrier, humid air might still find its way in. So we always suggest installing a dehumidifier. It's great at sucking moisture out of the air and keeping the moisture level below 55% year-round. 

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The benefits of encapsulating your crawl space

There are several benefits to crawl space encapsulation: 

  • Improves air quality
  • Eliminates pest infestations
  • Reduces humidity issues
  • Lowers heating and cooling costs
  • Prevents mold growth
  • Eliminates bad odors
  • Prevents structural damage

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How much does crawl space encapsulation cost?

At this point, you're probably wondering how much this is going to cost. Unfortunately, it's not so black and white. Every home is different and every crawl space has its own set of problems. A few factors can affect the price including:

  • The size of your crawl space
  • How tall the crawl space is
  • The condition of your crawl space
  • The type of work that will be done

It's best to reach out to a contractor to inspect and give you a quote based on their findings.

What's next?

If you're in our service area, please reach out to us. We'd love to help and determine what's the best solution for your crawl space. 

If you have any questions or would like a free consultation, call us at 515-493-7982 or reach out through this form. We'd be happy to answer any questions or help in any way we can.

our service area

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Our Locations:

Midwest Foundation Repair
9850 Douglas Ave Suite 100
Urbandale, IA 50322