Closed-Cell vs Open-Cell Spray Foam Best for Michigan Homes

Published February 4th, 2026

When it comes to insulating homes and commercial buildings in Michigan, the choice of spray foam insulation can make a significant difference in comfort and energy efficiency. Spray foam insulation is a high-performance solution designed to create a tight building envelope that reduces drafts, controls moisture, and keeps indoor temperatures stable through the region's harsh winters and humid summers. Among the options available, two main types stand out: closed-cell and open-cell spray foam. Each has unique characteristics that influence how well it performs under Michigan's demanding climate conditions.

Deciding between these two can feel overwhelming, but understanding their differences - especially in terms of thermal resistance, air sealing, moisture management, and structural impact - can help homeowners and builders select the best fit for their specific needs. This overview will guide you through the essentials of closed-cell versus open-cell spray foam, setting the stage for a clearer, more confident insulation choice that enhances your property's durability, comfort, and energy savings. 

Core Differences Between Closed-Cell and Open-Cell Spray Foam

Both closed-cell and open-cell spray foam start as liquids that expand and harden in place, but their internal structure and performance are very different. Understanding that structure is the key to choosing the right product for each part of a house.

What Closed-Cell Spray Foam is

Closed-cell spray foam forms millions of tiny, rigid bubbles. The "cells" stay sealed, so gas is trapped inside each one. That tight structure gives the foam a hard, dense feel when cured.

Closed-cell foam typically has a higher R-value per inch than open-cell. In practical terms, it takes fewer inches of closed-cell to reach the same insulation value. Its higher density also adds stiffness to framing, sheathing, and roof decks.

Because the cells stay sealed, closed-cell foam is highly resistant to air movement through the material. When installed correctly, it serves as both an insulator and a strong air barrier in wall cavities, rim joists, and roof assemblies.

What Open-Cell Spray Foam is

Open-cell spray foam also expands and fills gaps, but its bubbles intentionally break open as it cures. Those open pockets give it a softer, spongier texture and a lower density than closed-cell.

Open-cell foam has a lower R-value per inch, so it takes more thickness to reach the same thermal performance. It still provides excellent air sealing when properly applied, because air does not flow freely through the foam once the cavities are filled.

Its lighter nature makes it suited to areas where depth is available and added structural stiffness is less critical, such as many attic insulation and interior wall applications.

How Structure Affects Performance

• Insulation value (R-value per inch): Closed-cell delivers more R per inch, which matters where space is tight or you want maximum performance in a thin assembly.
• Density and rigidity: Closed-cell is dense and firm, helping brace the assembly. Open-cell is lighter and more flexible, which eases trimming and reduces added load on framing.
• Air sealing: Both types, when properly installed, create strong air barriers by expanding into cracks and joints. Closed-cell does it with a harder shell, while open-cell uses thickness and full cavity fill.

Those core physical differences set the stage for how each foam behaves with moisture, temperature swings, and long-term durability in a Michigan climate. 

Performance in Michigan's Climate: Cold Winters and Moisture Challenges

Michigan pushes insulation hard. Long stretches of subfreezing weather, quick spring and fall temperature swings, and humid summers expose weak spots in any building assembly. Spray foam choice needs to match those pressures, not just look good on a spec sheet.

Thermal Performance in Real Cold

Closed-cell spray foam tends to hold its effective R-value better in deep cold because of its dense, gas-filled structure. In rooflines, rim joists, and exterior walls that see wind and low temperatures, that stable performance helps cut drafts and cold spots along floors and ceilings.

Open-cell foam still insulates well in these conditions, especially when there is room to install a thicker layer. In attics with enough depth, open-cell spray foam attic insulation can reach strong total R-values. The foam's continuous coverage reduces convective looping inside cavities, which lowers heat loss even when outdoor temperatures drop sharply.

Air Sealing in a Climate With Temperature Swings

Both foams expand and bond to framing, which limits air leakage from stack effect in winter and hot air infiltration in summer. Closed-cell's rigid surface resists shrinkage and minor movement, which is useful where framing sees repeated freeze - thaw cycles or wind wash.

Open-cell foam's flexibility helps it stay adhered when lumber moves with seasonal humidity changes. In many attic and roof assemblies, that flexible seal tightens up air pathways that fiberglass or cellulose leave open around electrical penetrations, top plates, and blocking.

Moisture, Vapor, and Building Durability

Cold-climate performance is not just about heat. Moisture resistance is critical to protect sheathing, roof decks, and framing from condensation, mold growth, and long-term decay.

Closed-cell foam is highly resistant to water absorption and acts as a strong vapor retarder at typical install thicknesses. In areas with exterior sheathing exposed to cold winter air, that vapor control reduces the risk of warm indoor air driving moisture into cold surfaces where it can condense.

Open-cell foam is more vapor-permeable. That can be helpful in some interior conditions, but in a climate with cold winters and humid summers it demands a more deliberate approach. You often pair it with separate vapor control layers or smart membranes so moisture is managed instead of trapped where you do not want it.

For building durability, the key is balancing air sealing, thermal resistance, and moisture management as a system. Spray foam insulation for cold climates has to limit heat loss, block uncontrolled airflow, and direct vapor in a predictable way. When those three pieces line up, interior surfaces stay warmer, framing stays drier, and rooms feel more stable from January through August, setting the stage for any later cost and material comparisons. 

Durability, Structural Benefits, and Installation Considerations

Closed-cell and open-cell foams both seal and insulate, but they do very different things for the structure itself. That difference matters when a roof is holding snow or a wall sees steady wind pressure.

Structural Reinforcement and Long-Term Stiffness

Closed-cell spray foam has a higher density and a harder cured surface. When it bonds to studs, sheathing, or roof decking, it acts almost like a thin structural panel glued to the framing. This added rigidity distributes loads over a wider area instead of letting individual members flex on their own.

On roof decks under heavy snow, that extra stiffness helps limit deflection between rafters. In walls that face prevailing winds, it reduces racking movement and vibration. Those small movements are what loosen fasteners, open up cracks, and stress joints over time. Closed cell spray foam structural support does not replace proper framing, but it supports it, especially at corners, rim joists, and roof transitions.

Open-cell foam does not contribute the same level of bracing. Its lower density and softer texture mean it follows the framing rather than stiffening it. That flexibility still has value where sound control, lighter weight, or easy trimming matter more than added structural support.

Installation Thickness, Curing, and Assembly Design

Because closed-cell foam has higher R-value per inch, installers often target thinner passes to reach design performance. That controlled thickness also keeps the material within manufacturer limits so it cures evenly and maintains adhesion. Multiple lifts may be used for deeper cavities to manage heat during curing and avoid internal stress.

Open-cell foam is applied thicker in one pass because it generates less heat and expands more. Cavities fill completely, then get trimmed flush. The trade-off is that assemblies need enough depth to carry the required thermal value, especially in spray foam insulation for cold climates where code or comfort targets are higher.

Both materials need the right substrate conditions: dry surfaces, stable temperatures, and compatible wraps or coatings. On metal buildings common in Michigan, closed-cell foam bonds well to steel panels and adds noticeable panel stiffness while resisting condensation against the cold metal. Open-cell foam is more selective there, often reserved for interior framed builds where vapor control comes from other layers.

Installation quality drives durability as much as product choice. Correct lift thickness, even coverage, and attention to transitions between materials are what turn closed cell spray foam benefits on paper into a tighter, quieter building that holds its shape season after season. 

Cost Comparison and Value: What Michigan Homeowners Should Expect

Cost is usually where the closed-cell versus open-cell decision sharpens. Both require professional equipment and trained installers, so the labor side starts from a similar baseline. The real spread comes from material density, required thickness, and how each foam fits the assembly.

Upfront Cost: Why Closed-Cell Runs Higher

Closed-cell spray foam uses more raw material per inch and carries a higher price per board foot. Because its R-value per inch is higher, you often install less thickness to hit code or design targets, but the installed cost per square foot still comes in above open-cell in most wall and roof applications.

Open-cell foam uses less material mass and is faster to build depth in open cavities. That usually means a lower installed cost per square foot, especially in attics and interior walls where you can use generous thickness without crowding the assembly.

Lifetime Value: Energy, Durability, and Moisture Control

In a Michigan climate, the long-term numbers hinge on heating load, air leakage, and spray foam insulation moisture control. Closed-cell often delivers more value where:

• Snow, wind, and deep cold drive heat loss through exterior walls and rooflines.
• Condensation or bulk water are concerns, and stronger moisture resistance spray foam is needed against sheathing or metal panels.
• Assemblies benefit from added stiffness that keeps finishes and joints tighter over time.

In vented attics or large, open roof planes with plenty of depth, the open cell spray foam advantages are clear on cost. You reach high total R-values with a lower material bill, and strong air sealing still trims heating and cooling loads. Over the life of the building, the savings come from reduced energy use and fewer comfort complaints rather than structural reinforcement.

What Drives Pricing on Michigan Projects

Several project variables move the final number more than people expect:

• Building size and layout: Simple rectangles cost less per square foot than chopped-up floor plans with many corners, dormers, and transitions.
• Access and height: Tall walls, steep roofs, and tight crawlspaces slow production and add setup time.
• Required R-values and thickness: Local energy code and cold-climate targets push wall and roof assemblies toward higher R, which affects how many inches of each foam go in.
• Substrate condition: Time spent drying out damp framing, cleaning surfaces, or dealing with existing materials raises labor, even when the foam choice stays the same.

When you line those pieces up, the budget picture gets clearer. Closed-cell often commands a higher initial bill but brings tighter moisture control, added rigidity, and reliable performance in thin or exposed assemblies. Open-cell usually wins on upfront price in areas with ample depth, while still delivering strong air sealing and solid energy savings over time. 

Making the Right Choice for Your Michigan Property

Choosing between closed-cell and open-cell spray foam is less about which product is "better" and more about matching the foam to the job. Climate, exposure, assembly depth, moisture risk, and budget all pull the decision in specific directions.

Start by mapping out where the foam will go and what each area faces:

• Exterior walls, rim joists, and metal or low-slope roofs: Often favor closed-cell for higher R-value per inch, added stiffness, and stronger vapor control.
• Vented attics, deep rafter bays, and interior partitions: Frequently suit open-cell, where thickness is available and cost per square foot matters more than extra rigidity.
• Known or suspected moisture loads: Require clear vapor strategy, whether that comes from closed-cell, separate vapor control layers, or a combination.

Professional evaluation ties these pieces together so the whole assembly works: structure, insulation, vapor movement, and code requirements. With a sound design and competent installation, spray foam insulation for cold climates becomes a strategic investment instead of a gamble, trading short-term cost for steadier temperatures, drier framing, and lower energy use year after year.

Choosing the right spray foam insulation is essential for Michigan properties facing cold winters, humidity, and seasonal temperature swings. Both closed-cell and open-cell foams offer unique benefits that address different challenges - from maximizing thermal efficiency and air sealing to managing moisture and structural support. With over a decade of hands-on experience, CKC Industries Michigan, stands ready to guide you through these choices with expert advice and professional installation. Our licensed team prioritizes quality workmanship and tailored solutions that enhance your home's energy efficiency, durability, and comfort. Whether your project calls for the dense protection of closed-cell foam or the flexible coverage of open-cell, we ensure proper application that meets the demands of Michigan's climate. Reach out to learn more and get a thorough assessment of your insulation needs. Partner with trusted local professionals who deliver lasting results and peace of mind for your home or business.