Understanding the Two Types of Spray Foam
Spray foam insulation is one of the most effective solutions for sealing and insulating buildings today. At PolyCon, we manufacture both open-cell spray foam and closed-cell spray foam — each designed for specific needs on the job site. While both provide excellent insulation and air sealing, they perform differently when it comes to moisture, structural support, and cost.
Here’s a breakdown to help you choose the best option for your next project.
Open-Cell Foam: Lightweight and Flexible
Open-cell foam is soft, airy, and highly expandable. It fills in gaps and hard-to-reach areas with ease, making it a great choice for interior applications where sound absorption and air sealing are key.
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Density: ~0.5 lb/ft³
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R-Value: ~R-3.5 to R-3.7 per inch
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Expansion: Up to 100x its liquid volume
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Air Barrier: Yes
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Moisture Barrier: No
Where It Works Best:
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Interior walls and ceilings
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Sound-sensitive areas like media rooms and offices
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Budget-conscious builds where thickness isn’t an issue
Why Contractors Use It:
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More affordable than closed-cell
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Great at dampening sound
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Expands to fill irregular cavities
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Easy to work with in tight spaces
Closed-Cell Foam: Dense, Durable, and Waterproof
Closed-cell foam is rigid and tightly packed. It offers higher R-values per inch, acts as a vapor barrier, and adds structural support to walls and roofs.
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Density: ~2 lb/ft³
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R-Value: ~R-6 to R-7 per inch
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Expansion: ~30x its liquid volume
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Air Barrier: Yes
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Moisture Barrier: Yes
Where It Works Best:
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Exterior walls, roofs, and basements
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Areas exposed to moisture or weather
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Thin cavities that need high insulation value
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Metal buildings and commercial projects
Why Contractors Use It:
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Delivers top-tier insulation in less space
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Provides moisture control in damp environments
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Increases structural rigidity
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Long-lasting and durable
Cost Consideration
Closed-cell foam has a higher upfront cost, but its thermal performance and durability can lead to long-term energy savings — especially in demanding environments. Open-cell foam is a solid choice for cost-effective comfort in dry, interior spaces.
Still Not Sure Which to Use?
Choosing the right foam comes down to your project goals. If you’re insulating a crawlspace, basement, or roof — closed-cell is likely your best bet. For interior walls or soundproofing? Open-cell may be the right call.
Need help deciding? Give us a call. The PolyCon team is here to guide you from product selection to installation best practices.