Serving Commerce Township, MI & Southeast Michigan Since 2000
Open Cell vs. Closed Cell Spray Foam Explained
Open Cell vs. Closed Cell Spray Foam: What's the Difference?
When homeowners in Commerce Township and across Southeast Michigan ask about spray foam insulation, the first question is almost always: open cell vs. closed cell — which one do I need? Both are spray foam insulation products, but they behave very differently and are best suited for different applications. Understanding the difference between open cell and closed cell spray foam is the key to making the right choice for your home.
Jack Stimach from Seal Tech Insulation demonstrates the difference with what he calls the "Pillow Test" — squeeze open cell foam and it compresses like a pillow. Try the same with closed cell foam and it's rock hard. That physical difference tells you everything about how each product performs. Learn more from the Energy Star Seal & Insulate program and the Michigan Department of Environment, Great Lakes, and Energy (EGLE).
Video Transcript & Summary — The Pillow Test
0:00 - The question: Jack Stimach from Seal Tech Insulation introduces the open cell vs. closed cell debate and asks: is your home an echo chamber? He holds up samples of both foam types to show the physical difference.
0:10 - The Pillow Test: Jack squeezes the open cell foam — it compresses softly, like a pillow. He then squeezes the closed cell foam — it doesn't budge. This simple test illustrates the core structural difference between the two products.
0:25 - Open cell explained: Open cell spray foam has a soft, spongy structure because the cells are not fully closed. This makes it exceptional for sound dampening — it absorbs sound waves rather than reflecting them. It also provides excellent thermal performance at a lower cost per square foot. Best used in interior walls, attics with conditioned space, and anywhere sound control is a priority.
0:45 - Closed cell explained: Closed cell spray foam is dense and rigid because every cell is sealed. It delivers R-6 to R-7 per inch — nearly double the R-value of open cell — and acts as a vapor barrier. It's the right choice for crawl spaces, rim joists, exterior walls, and anywhere moisture or structural reinforcement is needed.
Open Cell vs. Closed Cell: Side-by-Side Comparison
☁️ Open Cell Spray Foam
- Soft, spongy texture — compresses like a pillow
- R-3.5 to R-3.7 per inch
- Excellent sound dampening
- Vapor permeable — breathes
- Lower cost per square foot
- Best for: interior walls, attics, sound control
- Not recommended for: below-grade, crawl spaces, exterior exposure
🧱 Closed Cell Spray Foam
- Dense, rigid structure — rock hard
- R-6 to R-7 per inch
- Acts as a vapor barrier
- Adds structural rigidity to walls
- Higher cost, higher performance
- Best for: crawl spaces, rim joists, exterior walls, below-grade
- Not recommended for: budget-sensitive interior applications
Detailed Comparison: Open Cell vs. Closed Cell Spray Foam
| Feature | Open Cell Spray Foam | Closed Cell Spray Foam |
|---|---|---|
| R-Value per inch | R-3.5 to R-3.7 | R-6 to R-7 |
| Texture | Soft, spongy (like a pillow) | Dense, rigid (rock hard) |
| Vapor barrier | No — vapor permeable | Yes — Class II vapor retarder |
| Sound dampening | Excellent | Good |
| Structural strength | None | Adds rigidity to walls |
| Cost | Lower | Higher |
| Best applications | Interior walls, attics, sound control | Crawl spaces, rim joists, exterior walls |
| Moisture resistance | Absorbs moisture — not for wet areas | Resists moisture — ideal for crawl spaces |
| Michigan code compliance | Meets code in most interior applications | Meets or exceeds code in all applications |
Which One Is Right for Your Commerce Township Home?
The honest answer is: most Michigan homes need both. Seal Tech typically installs closed cell spray foam in crawl spaces, rim joists, and exterior wall cavities — where moisture resistance, high R-value per inch, and vapor control are critical. Open cell spray foam is often the right choice for attic rafters in conditioned attic spaces and interior walls where sound dampening is a priority and moisture is not a concern.
During a free home evaluation, Seal Tech's experts will assess your specific home in Commerce Township, West Bloomfield, or Milford and recommend the right product for each location. There is no one-size-fits-all answer — the right choice depends on your home's construction, your climate zone, and your goals for comfort, energy savings, and budget.
Commerce Township, MI Note: Commerce Township homes — especially those near Wolverine Lake and the many lakefront properties in the area — often deal with elevated moisture levels in crawl spaces and basements. Closed cell spray foam is the correct choice for these applications, as it creates a vapor barrier that open cell foam cannot provide.
Where Each Type of Spray Foam Is Typically Installed
- Crawl spaces: Closed cell — moisture resistance and high R-value per inch are essential
- Rim joists: Closed cell — small area, high heat loss, needs maximum R-value and air seal
- Exterior wall cavities (2x4 or 2x6): Closed cell — meets Michigan's R-15 continuous requirement in less space
- Attic rafters (conditioned attic): Open cell or closed cell — depends on moisture conditions
- Interior walls (sound control): Open cell — superior sound dampening at lower cost
- Basement walls: Closed cell — vapor barrier properties protect against moisture intrusion
Seal Tech Serves All of Southeast Michigan
Seal Tech Insulation installs both open cell and closed cell spray foam insulation for homeowners and businesses across Southeast Michigan. We serve:
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📍 Serving Commerce Township & SE Michigan
We install open cell and closed cell spray foam insulation in Commerce Township, West Bloomfield, Milford, and 20+ more cities across Southeast Michigan.
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