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Crawl Space Insulation: Virginia’s Ultimate Guide

No one wants to get out of bed on a cold night and step on ice-cold floors or sweat inside their own home during the Virginia summers.  

Unfortunately, without proper crawl space insulation, that’s exactly what happens—but it can be fixed. In this article, you’ll learn what the best type of crawl space insulation is, how proper insulation saves you money, and how it makes your home more comfortable overall. Let’s dig in!

What Can Damage Your Insulation?

Falling insulation in crawl space.

When you think of a typical “nasty” crawl space, does moldy, sagging fiberglass insulation come to mind? Well, that’s often the reality in a crawl space that has zero protection from moisture. 

Fiberglass insulation was probably installed by whoever built your home. It’s a cheap insulation option that is easy to install, so it’s ideal when a home needs to be constructed by a certain time.

Unfortunately, Virginia’s high humidity means it doesn’t take long for fiberglass insulation to end up damaged. As you can see pictured here, typical fiberglass insulation starts to sag when it absorbs water, making it the perfect breeding ground for mold and mildew.

It’s also a great home for rodents and pests.  Removing this insulation and replacing it with better insulation is the only way to solve the problem. 

How to Properly Insulate a Crawl Space

Today we know a lot more about crawl spaces and understand that any organic material can be damaged if the crawl space isn’t properly sealed.  Encapsulation involves insulating the crawl space walls and sealing the floor from outside air and water.  

Wall insulation board installed without sealing the floor will provide little benefit as conditioned air will escape through the untreated dirt floor.  Each home is unique, and never has this been truer than in Virginia.

When considering crawl space insulation, a plan should be designed to best meet the needs of the specific crawl space. Still, here are the general steps for crawl space insulation:

1. Clean & Remove Old Insulation

Before work can begin, it’s best to clean the crawl space of old building materials and trash. Existing damaged insulation should be bagged and removed. Make sure to call a professional for this job, as fiberglass insulation can cause injury without the proper equipment and protection.  

Removal of old crawl space insulation.

2. Install Drainage

Once the insulation is removed, it’s time to start addressing the cause behind moisture in your crawl space. One of the best ways to do this is by installing crawl space drainage. Installing a full drainage system includes drainage matting, a sump pump, and a crawl space drain. JES can install all of these water management tools for you—it’s best to work with a professional.

Crawl space drainage pipe.

3. Seal Vents

While open crawl space vents were originally thought to be a helpful design, we now know that isn’t the case. Instead of allowing optimal airflow, vents actually lead to moisture issues. Building America researched crawl spaces and found unvented crawl spaces use 15% to 18% less energy and reduce humidity by 20%. Because of this data, the next step is to seal any existing vents with airtight material. 

Sealing crawl space vents.

4. Install Foam Board Insulation

JES installs rigid closed-cell foam board insulation with an R rating of at least 10. The board also has a radiant barrier, meaning it reflects heat into the crawl space. These Insulation panels are installed on the walls of the crawl space using a mechanical fastener. Building code requires an opening near the top of the wall to check for termite activity. Since each city has different regarding requirements, it’s best to work with a company like JES with certified installers.

Installing crawl space insulation boards.

5. Encapsulate the Crawl Space

With the new insulation installed, you can encapsulate the crawl space to create a controlled environment. Usually, this involves installing a vapor barrier and dehumidifier that block and remove humidity from the crawl space. You might also consider installing crawl space support jacks for sturdy floor support. With all of these tools installed, you won’t deal with damaged insulation again!

A finished crawl space that has been encapsulated.

How Insulation Protects Your Crawl Space

While insulating your crawl space is just part of the encapsulation process, it is a very important part. Insulation regulates the temperature throughout your home, making it feel warmer in the winter and cooler in the summer. This translates to lower energy bills year-round. 

Keeping the space beneath your home warm also means your floors stay warmer during Virginia’s chilly winters. One of the biggest advantages, however, is frozen pipe prevention. Warming the area means your pipes are less likely to freeze, saving you a big headache.

Install Better Crawl Space Insulation with JES Foundation Repair

JES has been transforming homeowners’ crawl spaces since 1993. Working with JES means you’ll get professional repairs and quality customer service.  If you’re looking to install insulation in your crawl space, don’t hesitate to contact us today. We’ll make sure your home stays protected for years.  


Selecting the right insulation for a crawl space is unique to any other area of your home. Look for a ridged, closed-cell foam that provides a thermal barrier and has at least an R-10 value.

Absolutely. Insulating your crawl space saves money by creating a warmer and more even temperature both in the crawl space and the living area of your home.  

Insulating the floor over your crawl space isn’t necessary if the crawl space is properly encapsulated. Insulation on the walls and a vapor barrier on the floor seal out outside air, keeping the temperature stable.  

Adding insulation to the floor would only increase the cost.

JES Can Help Encapsulate
Your Crawl Space

Our team at JES Foundation Repair is proud to serve homeowners in locations throughout Virginia, including: 

  • Charlottesville 
  • Chesapeake 
  • Fredericksburg 
  • Hampton 

Don’t see your service area? Check here.

Phillip Mazzotta

Phillip Mazzotta

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JES Foundation Repair service area map of the Mid-Atlantic region.

Our Locations


8361 Town Center Ct
Nottingham, MD 21236


311 Central Rd.
Suite 2-02
Fredericksburg, VA 22401

Hampton Roads & NE NC

2569 Quality Ct
Virginia Beach, VA 23454

Northern VA & DC

7940 Gainsford Ct.
Bristow, VA 20136


309 Quarles Rd
Ashland, VA 23005

Southwest Virginia / Roanoke

2033 Cook Dr.
Salem, VA 24153

Western Virginia

456 Old Courthouse Rd
Appomattox, VA 24522


45 W Boscawen St,
Winchester, VA 22601