Does an Encapsulated Crawl Space Need Insulation? A Helpful Guide

According to a recent survey, approximately 68 percent of homeowners began or completed a home improvement project in the last year. This may be attributable to higher mortgage rates and lower inventory–homeowners see this as a window to make their home more appealing and also more livable. 

This includes improvements in and underneath the home, including crawl space encapsulation. This is a complex undertaking with many different options. 

You may be wondering, “Does an encapsulated crawl space need insulation?” The short answer is, “It depends.” Each home is unique, and many different factors will determine whether you should insulate or encapsulate (or both). 

Below is a guide to insulating and encapsulating crawl spaces. It provides information on how these two upgrades affect one another and how they each impact the air quality of the crawl space and throughout your home. Keep reading to learn more. 

What Is Crawl Space Encapsulation?

In order to answer “Does an encapsulated crawl space need insulation?” it is important to understand how encapsulation works. In general, it involves wrapping a water vapor barrier on the floors and walls of the crawl space. This creates a clean, dry “capsule.”

Home crawl space barriers are often made of heavy-duty plastic, such as polyethylene, which keeps ground or exterior moisture from creeping in. The goal is usually to better control humidity levels in the space. 

This is also important because the majority of the air in our homes comes up from the basement or crawl space. An extremely humid crawl space translates to more difficulty controlling moisture levels throughout your home. It also creates an environment where mold and mildew can thrive. 

Before installing the encapsulating materials, technicians will assess and clean the space. They will keep a close eye out for rocks, nails, or sharp objects that could damage or puncture the material.

Then, they will install the barrier on the foundation walls and floors. They will use special tape to seal areas where separate pieces overlap. 

Crawl space barriers are great for keeping moisture out, and they do have some insulating qualities. However, these are minimal. For this reason, many people consider insulating an encapsulated crawl space. 

How Does Crawl Space Insulation Work?

Insulating crawl spaces can go hand-in-hand with encapsulation. It provides an added level of protection from outside air, which can lead to increased moisture.

Insulating a crawl space can be beneficial if you are concerned about extreme temperatures underneath your home. This can lead to “cold floors” and frozen pipes.

Installing insulation will protect this area and help regulate the temperature inside your home. This in turn means your HVAC system does not have to work as hard or run as long, which can save lots of money on utility bills. 

There are three main types of insulation: fiberglass batts, foam boards, and spray foam. Fiberglass and special foam boards are the best choice.

Spray foam tends to be more expensive. It virtually eliminates leakage by creating an air-tight seal. This also means it helps retain hot or cold air in the space where it is installed. 

There is a major caveat here, especially as it relates to spray foam insulation on floor joists & subfloor. It is that spray insulation is extremely difficult, time consuming, and expensive to remove, once it is in place.

This means that, for instance, if you experience a leak inside your home that impacts your floor joists or subfloor, you can expect to have a very difficult time doing repairs from the crawl space area. For this reason, it’s best to consider going with foam board or fiberglass batt insulation. 

Does an Encapsulated Crawl Space Need Insulation?

For starters, it is best to encapsulate and insulate a crawl space. Since they serve unique functions, both may be suitable. 

While insulation will prevent hot and cold air from escaping (or entering) your crawl space, it will not keep out moisture. Conversely, encapsulation without insulation will keep moisture away but will not keep hot and cold air in/out. If you have issues with moisture/humidity and cold or hot temperatures in your crawl space, then you probably need both encapsulation and insulation. 

There are benefits to doing both insulation and encapsulation, including better energy efficiency. A well-insulated home may still experience issues with humidity, which can lead to mold, and mildew, and make your HVAC system work harder to remove moisture from the air. Encapsulation can go a long way toward controlling moisture but does very little to help regulate your home’s temperature. 

How Does Insulation Work With an Encapsulated Crawl Space?

What we recommend is to insulate the crawl space walls with foam board insulation and seal the vents with vent covers and foam insulation blocks.

Some combination of insulation products may be useful for combining with encapsulation. For instance, you might use foam boards for the majority of the area but spray foam only for hard-to-reach areas. A qualified technician will be able to advise you on which is best for your crawl space. 

If you are looking for both encapsulation and insulation, it can still be done in as little as a day for small spaces. How long installation takes will depend on the status of your crawl space. 

For instance, if technicians need to remove existing insulation to install a vapor barrier, this could take a bit longer. Regardless of the condition of the job site, encapsulation and insulation services should take no longer than a few days to a week, if performed by professional installers. 

Learn More About Insulating and Encapsulating a Crawl Space

Now that you have an answer to “Does an encapsulated crawl space need insulation?” you can move forward with your project. Understanding your goals and employing the home improvement tips above will keep you on the right track. 

BAY Crawl Space and Foundation Repair is an award-winning repair contractor serving Norfolk, VA, and the surrounding areas. We have ranked in the top 5 percent in the U.S. for Super Service Awards for six years running. Reach out to us today to get a free estimate on crawl space repair or improvement.