Open-Cell vs. Closed-Cell Spray Foam: Choosing the Right Insulation

Spray foam insulation is one of the most versatile solutions for sealing, insulating, and protecting buildings. But not all spray foam is the same — the two main types, open-cell and closed-cell, offer different benefits depending on your project.

To make the choice clearer, let’s compare HandiFoam® HFO Open Cell (an open-cell spray foam) with Froth-Pak™ Insulation Kits (closed-cell spray foams like Froth-Pak™ 630 or 200).

What’s the Difference?

  • Open-Cell Foam: A lighter, softer foam with interconnected cells. It expands to fill cavities easily and is excellent at sound absorption, but it’s vapor-permeable and not moisture-resistant.
  • Closed-Cell Foam: A denser, rigid foam with sealed cells. It provides higher R-value per inch, resists water, and even adds structural strength and is less flexible.

Key Technical Differences

HandiFoam® HFO Open Cell (Open-Cell Foam)

  • Density: ~0.72 lb/ft³ (free rise); ~1.64 lb/ft³ in place
  • R-Value: 6.1 at 1" (initial), 4.4 aged; 21.9 at 4" (initial), 16.5 aged
  • Open-Cell Content: >90%
  • Compressive Strength: ~2.2 psi
  • Fire Rating: ASTM E84 Class B, Flame Spread 65, Smoke 450
  • Applications: Filling voids, reducing vibration, interior insulation where sound dampening and flexibility are valuable.

Froth-Pak™ Insulation (Closed-Cell)

  • Density: ~1.75 lb/ft³
  • R-Value: 6.7 per inch (initial), 6.2 aged at 1", 12.2 at 2" (≈6.7 per inch)
  • Air Leakage: As low as 0.0088 L/sec·m² @ 75Pa
  • Water Vapor Permeance: ~5.4 perms @ 1", 3.1 perms @ 2"
  • Fire Rating: Class A flame spread
  • Applications: Roof and wall junctions, basements, crawlspaces, electrical/mechanical penetrations, attics, cold storage, and areas where moisture resistance and high insulation are critical.

Applications in the Real World

Open-Cell Foam (HandiFoam® HFO Open Cell)

  • Interior walls: Soundproofing between rooms.
  • Attics & ceilings: Expands to fill large cavities, improving energy efficiency.
  • Renovations: Flexible fill for irregular gaps and retrofits.
  • Lightweight projects: Where lower density is acceptable.

Closed-Cell Foam (Froth-Pak™ 630, 200)

  • Exterior walls: High R-value in thin cavities.
  • Basements & crawlspaces: Resists moisture and mold.
  • Roof perimeters & wall junctions: Creates a strong, air- and water-resistant seal.
  • Industrial & commercial uses: Cold storage, mechanical penetrations, masonry and metal bonding.
  • Structural reinforcement: Adds rigidity and durability to walls and substrates.

Which Should You Choose?

  • Choose HandiFoam® HFO Open Cell when:
    • Sound dampening is a priority.
    • Large, irregular cavities need to be filled.
  • Choose Froth-Pak™ Insulation when:
    • You’re sealing exterior walls, basements, crawlspaces, or roofs.
    • You need high R-value per inch.
    • Moisture control and structural support are essential.

Both open-cell and closed-cell foams are powerful solutions, but their strengths lie in different areas.

  • HandiFoam® HFO Open Cell is best indoors where sound control and expansion matter.
  • Froth-Pak™ closed-cell kits deliver high-performance insulation and moisture protection in tougher environments.

By understanding these differences, you can select the right foam for each project and ensure long-lasting comfort, efficiency, and protection.

Check out our Handi-Foam Open Cell Kits here!

Check out out Froth-Pak Closed Cell Foam Kits here!

Sep 18th 2025 AWarehouseFull

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