Skip to Main Content

Crawl Space Insulation Types: Best & Worst

Wet, old, hanging insulation inside a crawl space

Crawl space insulation is essential for maintaining a healthy, energy-efficient home. Proper insulation helps regulate your home’s temperature, reduces energy bills, and prevents moisture and mold issues.

However, choosing the right type of insulation for your crawl space is crucial. The wrong choice can lead to significant problems, undermining the benefits you’re aiming to achieve.

On this page, you’ll learn about the best and worst types of crawl space insulation to ensure you make the right choice for your home.

The Worst Types of Crawl Space Insulation

Selecting the wrong insulation for your crawl space can do more harm than good.

Two of the most common yet problematic types are fiberglass insulation and spray foam.

Wet, old, hanging, fiberglass insulation
  • Fiberglass Insulation: While common, fiberglass absorbs water, creating an ideal environment for mold growth. Once wet, its insulating properties are compromised, and it becomes a breeding ground for mold, negatively impacting indoor air quality.
  • Spray Foam: This option might seem appealing due to its initial insulating properties, but it has several downsides. Spray foam can emit a chemical smell and, like fiberglass, can harbor mold. Additionally, it can attract termites, leading to structural damage over time.

The Best Crawl Space Insulation: Rigid Foam Board

Closeup of ExTremeBlocâ„¢ thermal foam board

For optimal crawl space insulation, a rigid foam board is a superior choice.

Groundworks installs ExTremeBloc™, a thermal foam board featuring reflective surface panels for enhanced heat retention and insulation value.

These panels are precisely cut to fit your crawl space walls and come with a Class A safety rating.

ExTremeBloc™ ensures your crawl space remains dry and well-insulated, providing long-lasting benefits.

Benefits of Quality Crawl Space Insulation

Investing in high-quality crawl space insulation offers numerous advantages, including:

Groundworks employee installing foam board insulation
  • Moisture Control: Proper insulation helps manage moisture levels, preventing dampness and protecting your home’s structure.
  • Mold Prevention: Controlling moisture significantly reduces the risk of mold growth, which can negatively affect your health and home.
  • Fewer Pest Infestations: Quality insulation can discourage pests like termites and rodents from making your crawl space their home.
  • Long-term Energy Savings: Effective insulation helps maintain consistent temperatures, reducing the workload on your HVAC system and lowering energy bills.
  • Better Indoor Air Quality: High-quality insulation contributes to healthier indoor air by preventing mold and moisture issues.

Trust Groundworks for Expert Crawl Space Insulation Solutions

Finished, fully encapsulated crawl space

When it comes to crawl space insulation, Groundworks is the right choice.

With experience in repairing and insulating 1.5 million homes across the country, we have the expertise to handle any insulation job.

Trust Groundworks to deliver superior insulation that ensures the long-term health and efficiency of your home. Contact us today to schedule your free inspection and take the first step.


Signs that your crawl space needs insulation include cold floors, high energy bills, musty odors, and visible moisture or mold in the crawl space.

Yes, proper crawl space insulation can significantly reduce energy bills by preventing heat loss in the winter and heat gain in the summer.

While some homeowners may choose to install insulation themselves, it’s often best to hire a professional to ensure proper installation and address any underlying issues.

Leah Leitow

Leah Leitow

Content Writer

Leah is a Content Writer for Groundworks with nearly ten years of experience working in the foundation repair industry. Her experience ranges from working with homeowners to find the right solution to training inspectors and staff. In her background as a Michigan journalist, she gained invaluable insight into people's lives throughout our state. Leah lives in metro Detroit with her husband and two sons.