Best Cavity Wall Spray Foams in 2025: Full Buyer’s Guide

Cavity wall spray foam insulation has become one of the most efficient and popular methods for improving a building’s thermal performance, reducing energy bills, and enhancing indoor comfort. Whether you’re a contractor, homeowner, or building manager, choosing the right spray foam in 2025 requires understanding product types, certifications, R-values, and trusted brands.

This comprehensive guide covers everything you need to know about the best cavity wall spray foams in 2025, how to choose them, and where to buy them in the U.S. and Canada.

What Is Cavity Wall Spray Foam?

Cavity wall spray foam insulation is applied into the gap (cavity) between the exterior and interior walls of a building. Once sprayed, the foam expands to fill voids, sealing gaps and providing excellent insulation against temperature changes, air leakage, and moisture ingress.

Unlike traditional batt insulation or loose-fill, spray foam:

• Adheres directly to surfaces

• Expands into hard-to-reach areas

• Adds air sealing and vapor control

• Provides long-term energy savings

There are two main types:

1. Open-cell foam – Light, breathable, lower R-value, ideal for internal walls

2. Closed-cell foam – Denser, more rigid, higher R-value, moisture barrier, great for external cavity walls

Key Benefits of Cavity Wall Spray Foam in 2025

• Higher R-values (thermal performance) than traditional insulation

• Air barrier and vapor barrier in one application

• Improved soundproofing for interior comfort

• Moisture resistance – Prevents mold and mildew

• Long-term energy savings and fast ROI

• Increased structural integrity for the wall system

In 2025, innovations in chemistry and blowing agents—especially HFO-based foams—are making spray foams greener, safer, and more efficient.

What to Look for When Choosing Spray Foam for Cavity Walls

Before selecting a spray foam product, consider the following:

• R-Value per inch (Higher is better)

• Type of foam (Closed-cell vs Open-cell)

• Blowing agent (HFOs are more environmentally friendly than HFCs)

• ICC or CCMC certification (U.S. or Canada)

• Fire rating (Class I preferred)

• Water absorption rate

• Manufacturer support and warranty

Best Cavity Wall Spray Foams in 2025 (US & Canada)

1. Demilec Heatlok HFO High Lift

Best Overall for Energy Efficiency

This closed-cell spray foam uses an environmentally friendly HFO blowing agent and offers excellent thermal performance. It’s certified for use in cavity walls and performs well in both hot and cold climates.

Features:

• R-Value: 7.5 per inch

• Class I fire rating

• CCMC certified (Canada), ICC listed (USA)

• Low VOC, GREENGUARD Gold Certified

Best For: Commercial and residential cavity walls, both new construction and retrofit.

2. Icynene-Lapolla Ultra-Low GWP Foam

Best for Eco-Friendly Builds

Formulated with ultra-low GWP blowing agents, this closed-cell foam delivers robust performance while reducing environmental impact.

Features:

• R-Value: 6.9 per inch

• Contributes to LEED and green building certifications

• Used in both the U.S. and Canada

Best For: Passive houses, green-certified buildings, high-performance homes

3. Johns Manville Corbond III

Best for Fast Installations

A reliable spray foam product with excellent adhesion and fast cure time, making it a top choice for contractors.

Features:

• R-Value: 6.6 per inch

• Closed-cell, rigid insulation

• Class I fire rating

Best For: Cavity wall retrofits and time-sensitive jobs

4. Huntsman IcyFoam Select HFO

Best for Moisture Resistance

Huntsman’s HFO foam offers both high performance and resistance to moisture intrusion. It adheres well to various substrates.

Features:

• R-Value: 7.0 per inch

• Closed-cell, HFO-blown

• Low water absorption

• High dimensional stability

Best For: High humidity environments, coastal or wet climate zones

5. GacoFireStop Spray Foam (Fire-Retardant)

Best Fire-Resistant Option

For buildings requiring Class A or enhanced fire protection, GacoFireStop offers superior flame resistance.

Features:

• Closed-cell spray foam

• Class A fire rating

• Good thermal and moisture performance

Best For: Commercial buildings, multi-family units, code-sensitive applications

Where to Buy Spray Foam in the U.S. and Canada

You can purchase spray foam insulation kits or hire certified installers through:

• Home Depot

• Lowe’s

• Menards

• Spray foam suppliers like SPI, IDI, or Demilec dealers

• Amazon (for smaller kits and accessories)

For professional installations, look for licensed contractors with training from manufacturers like BASF, Huntsman, or Demilec.

DIY vs Professional Installation for Cavity Walls

While DIY kits are available, cavity wall insulation with spray foam is best left to professionals due to:

• Complex application (expansion and curing time)

• Health and safety concerns (ventilation and PPE)

• Building code compliance (especially in multi-family or commercial projects)

DIY kits can be useful for small repair jobs, garages, or sheds, but professional-grade equipment ensures consistent application and performance.

Certifications to Look For (US & Canada)

• ICC-ES (International Code Council – U.S. approval)

• CCMC (Canadian Construction Materials Centre)

• GREENGUARD Gold (low VOCs and indoor air safety)

• LEED credits (sustainability)

• ASTM E84 Class I (fire safety)

These certifications ensure you’re choosing a code-compliant and high-performing insulation product.

Final Thoughts: Choosing the Right Spray Foam in 2025

Cavity wall spray foam remains one of the smartest investments in building efficiency. With rising energy costs and stricter building codes, choosing a high-performance, certified, and environmentally safe spray foam has never been more important.

Among the best products for 2025, Demilec’s Heatlok HFO, Huntsman IcyFoam, and Icynene-Lapolla stand out for their superior R-values, sustainability, and performance. Always verify certifications, ask about warranties, and ensure professional installation for the best long-term results.

For more construction product reviews, buyer’s guides, and insulation tips, explore our full blog series on ProBuildChoice.com.