Spray Foam Insulation vs. Fiberglass

Cons of Spray Foam:

• Higher upfront cost
• Requires professional installation
• May be overkill in mild climates or vented crawl spaces

What Is Fiberglass Insulation?

Fiberglass insulation consists of fine glass fibers and typically comes in batts or rolls. It works by trapping pockets of air, slowing heat transfer. In crawl spaces, it can be wise to install fiberglass between floor joists.

Pros of Fiberglass:

• Less expensive than spray foam
• Readily available and easy to install in accessible areas
• Non-combustible and mold-resistant when kept dry

Cons of Fiberglass:

• Can absorb moisture if not protected by a vapor barrier
• Less effective at air sealing – may still allow drafts
• Loses insulating value if it sags, compresses, or gets wet
• Often attracts rodents looking for nesting material
• Shorter lifespan and more prone to damage

Which One Is Better for Crawl Spaces?

It depends on your crawl space conditions and your goals.

Choose spray foam if:

• You have a sealed or encapsulated crawl space
• You want superior moisture protection and air sealing
• You’re dealing with extreme temperatures or humidity
• Long-term performance and durability are a priority

Choose fiberglass if:

• You’re on a tighter budget
• Your crawl space is vented and well-drained
• You plan to add a vapor barrier to help control moisture
• The space is easy to access and you inspect it regularly

While fiberglass may still work in some cases, spray foam is typically a better long-term solution for moisture-prone areas like crawl spaces – especially when combined with encapsulation.

Let Crawl Space Ninja Help You Choose Insulation

Spray foam and fiberglass insulation require proper installation to be effective. Mistakes like gaps, compression, poor ventilation, or unsealed air leaks can reduce insulation performance and lead to future problems like mold or energy loss.

Crawl Space Ninja’s team offers:

• Expert evaluation of your crawl space’s unique conditions
• Custom insulation solutions tailored to your home and climate
• Safe, code-compliant installation
• A proprietary encapsulation solution backed by a lifetime warranty

Whether you’re replacing old insulation or starting from scratch, contact us today to schedule your crawl space evaluation and learn how we can help you enjoy a drier, healthier, more energy-efficient home.