--- title: "Open vs Closed Cell Spray Foam: Cost & Use in Florida" description: "Open vs closed cell spray foam in Florida: what drives the cost difference, R-value per inch, and which belongs on roof decks, walls or metal buildings." image: https://www.idealinsulationinc.com/hubfs/openvsclosecell.png --- [Skip to content](https://www.idealinsulationinc.com/insulation-blog/open-cell-vs-closed-cell-spray-foam-the-complete-comparison-guide#main-content) [IDEALINSULATION](https://www.idealinsulationinc.com/) [Services](https://www.idealinsulationinc.com/#services)[For builders](https://www.idealinsulationinc.com/insulation-contractor-for-builders-naples-fl-swfl)Explore [Home](https://www.idealinsulationinc.com/)[Spray foam](https://www.idealinsulationinc.com/services/spray-foam-insulation-naples-fl)[Attic insulation](https://www.idealinsulationinc.com/services/attic-insulation-naples-fl)[Insulation removal](https://www.idealinsulationinc.com/professional-insulation-removal-naples-fl-emergency-service-ideal-naples-swfl)[For builders](https://www.idealinsulationinc.com/insulation-contractor-for-builders-naples-fl-swfl)[Service areas](https://www.idealinsulationinc.com/areas-served-swfl)[Insulation guides](https://www.idealinsulationinc.com/insulation-blog)[Contact Ideal](https://www.idealinsulationinc.com/contact-us-ideal-insulation) [(239) 455-2002](tel:+12394552002) [Home](https://www.idealinsulationinc.com/) / [Insulation guides](https://www.idealinsulationinc.com/insulation-blog) Ideal Insulation · Southwest Florida # Open Cell vs Closed Cell Spray Foam: Cost, R-Value and Where Each Belongs ![](https://app.hubspot.com/settings/avatar/d41d8cd98f00b204e9800998ecf8427e)[Ideal Insulation](https://www.idealinsulationinc.com/insulation-blog/author/ideal-insulation) September 6, 2025 ![](https://www.idealinsulationinc.com/hs-fs/hubfs/openvsclosecell.png?width=2200&height=874&name=openvsclosecell.png) Not sure which foam your home needs? We'll recommend one in a written estimate. See [Fort Myers](https://www.idealinsulationinc.com/services/spray-foam-insulation-fort-myers-fl), [Cape Coral](https://www.idealinsulationinc.com/services/spray-foam-insulation-cape-coral-fl) or [Naples](https://www.idealinsulationinc.com/services/spray-foam-insulation-naples-fl) spray foam. Last Updated: September 30, 2026 | By Ideal Insulation Enterprises Open-cell and closed-cell spray foam can serve different needs. The useful comparison starts with your roof or wall assembly, available depth, moisture conditions and budget. Ideal Insulation serves Naples and Southwest Florida. This guide explains what to compare before choosing a product and requesting a project-specific estimate. > **The short answer:** Product choice depends on the roof or wall assembly, moisture strategy and required performance. For an unvented roof assembly, establish the required R-value from the approved plans and energy calculations, then use the selected foam product's published thickness table. Open-cell foam does not have a universal five-inch R-30 rating. Coordinate moisture control and ventilation with the assembly design.   ## What Is Spray Foam Insulation? Spray polyurethane foam expands during application to form insulation. At its tested thickness and with the surrounding joints properly sealed, it can also form part of an air-control system. Insulation and air sealing address different parts of home energy performance. Compare them as part of a whole-house plan rather than assuming one material solves every source of heat loss or air leakage. ## Open Cell Spray Foam: Complete Breakdown ### What Is Open Cell Spray Foam? Open cell spray foam gets its name from its cellular structure. The tiny bubbles that form during application aren't fully encapsulated—they're "open," allowing air to fill the spaces within the foam. This creates a softer, more flexible material with a spongy texture. Expansion and application limits vary by formulation. The installer should follow the selected product's application guide, including the permitted depth of each sprayed layer. ### Open-Cell Product Data: What to Compare The material-property examples below come from Carlisle's SealTite PRO Open Cell data sheet. They are not specifications for every open-cell foam or a statement that this product is selected for your job. Price rows retain this guide's separate pricing examples. | Specification | Value | | --- | --- | | Density | 0.5 lbs/ft³ | | R-Value Per Inch | R-3.7 at 1 inch | | R-Value at 3.5" (2x4 wall) | R-13 | | R-Value at 5.5" (2x6 wall) | See product data | | Tested Air Impermeability | At 3.5 inches | | Vapor Permeability | 21 perms at 1 inch | | Expansion Rate | See application guide | | Typical Specified Depth in SWFL | Full cavity depth in walls; roof-deck depth set by the approved R-value and the product's thickness table | ### Where Open-Cell Foam May Fit Open-cell foam is used in wall and roof assemblies where its insulation value, available depth and vapor permeability fit the design. Manufacturer approvals and required fire-protective coverings still apply. For a sound-control project, compare a tested complete wall or floor assembly. Foam type alone does not establish the sound isolation between rooms. ### Moisture and Depth Considerations Open-cell foam is vapor permeable. That does not make every Florida installation unsuitable: the assembly must manage rainwater, air leakage, vapor movement and drying. Choose any vapor-control layer for the actual assembly rather than adding an interior plastic barrier by default. Check the product's published R-value at the proposed thickness. A cavity depth does not, by itself, establish code compliance. ## Closed Cell Spray Foam: Complete Breakdown ### What Is Closed Cell Spray Foam? Closed-cell spray foam is denser and generally offers more thermal resistance per inch than low-density open-cell foam. Its vapor permeance also depends on the product and installed thickness. ### Closed-Cell Product Data: What to Compare The material-property examples below come from Carlisle's SealTite PRO Closed Cell data sheet. Use the actual proposed product's current data for your project. Price rows remain the guide's separate pricing examples. | Specification | Value | | --- | --- | | Density | 2.0 lbs/ft³ | | R-Value Per Inch | R-6.9 at 1 inch | | R-Value at 1" | R-6.9 | | R-Value at 2" | See product data | | R-Value at 3" | R-21 | | Tested Air Impermeability | At 1 inch | | Vapor Retarder Thickness | 1 inch for this product | | Expansion Rate | See application guide | | Vapor-Retarder Class at Installed Depth | Class II at 1 inch for the referenced product (0.8 perms); lower permeance at greater depth | ### Where Closed-Cell Foam May Fit Closed-cell foam can be useful when the design calls for greater R-value in a limited depth or lower vapor permeance. Confirm the specific product's listed uses and thickness before selecting it. Water resistance is not a promise that a wall, roof or crawl space will stay dry. Leaks, drainage, connections and drying paths still need attention. In flood-prone locations, check the required flood-resistant assembly and material approvals. PNNL's crawlspace guidance uses a specified closed-cell foam assembly and still requires cleaning exposed foam after floodwater contact. Do not use an insulation choice as a structural design assumption. Any claimed contribution to wind resistance needs evidence for the exact product and assembly. ## Open Cell vs Closed Cell: Direct Comparison ### Side-by-Side Comparison | Factor | Open Cell | Closed Cell | What to check | | --- | --- | --- | --- | | R-Value Per Inch | See product data | See product data | Check depth | | Moisture Resistance | Vapor open | Lower permeance | Check design | | Sound​proofing | Use test data | Use test data | No default | | Structural Support | No rating assumed | No rating assumed | Engineer | | Flood Resistance | Check approval | Check approval | Check site | | Air Sealing | Tested depth | Tested depth | Check joints | | Longevity | Warranty terms | Warranty terms | No fixed term | **Comparing spray foam for a Southwest Florida project?** Share the property address, roof or wall details, and any plans or photos so we can discuss the scope. [Request a spray-foam estimate](https://clienthub.getjobber.com/hubs/d0e0f91b-8c25-49dd-9fb4-6813040a7759/public/requests/4221726/new) or see our [Naples spray-foam services and completed local projects](https://www.idealinsulationinc.com/services/spray-foam-insulation-naples-fl). ### Why You Cannot Compare the Two by Thickness Alone The two foams are never specified at the same depth. Open cell is sprayed full-cavity because it needs roughly 3.5 inches to become an air barrier and more than that to reach roof-deck R-values. Closed cell is usually specified thinner because it reaches the target R-value sooner and becomes an air barrier and a Class II vapor retarder at one inch. So a "which is cheaper" question compares a full cavity of one product with a partial fill of the other, and only a written estimate for your actual square footage and the depth your assembly requires can answer it. Compare quotes against the same required performance and scope, including any specified air, moisture and fire-protection details. A separate vapor-control layer is not automatically required simply because a project is in Florida. ## Which Spray Foam Is Best for Florida? There is no single foam choice for every Florida home. Establish the insulation boundary, required R-value, moisture-control strategy and product approval before comparing price. ### Our Southwest Florida Recommendation > **Choose the product for the assembly, not from a blanket open-cell or closed-cell rule.** Bring the building plans or project details to the comparison. A roof conversion, a wood-framed wall and a metal building can require different insulation and moisture-control details. ### Application-Specific Recommendations for Southwest Florida #### Attics and Rooflines An unvented attic can place ducts and equipment inside the insulated enclosure. It also needs a coordinated plan for moisture removal, ventilation and any combustion equipment. A vented attic is not automatically a poor choice. For an unvented roof assembly, establish the required R-value from the approved plans and energy calculations, then use the selected foam product's published thickness table. Open-cell foam does not have a universal five-inch R-30 rating. Coordinate moisture control and ventilation with the assembly design. For example, Huntsman's Classic Ultra open-cell data lists R-30 at eight inches. The required thickness varies by product and approved assembly. #### Exterior Walls Check the wall layers, framing depth, water-control details and specified R-value. Use the selected foam's product data rather than a universal two- or three-inch rule. #### Interior Partition Walls For bedrooms or a home office, ask for the acoustic rating of the proposed wall assembly, including framing, finishes, penetrations and insulation. Neither foam type makes a room soundproof by itself. #### Crawl Spaces and Below-Grade Areas Start with drainage, ground moisture and any flood requirements. Product approval and the complete assembly determine suitability; foam alone does not convert a damp space into a dry one. #### Metal Buildings and Pole Barns Determine how the building will be used and conditioned before specifying the insulation. Condensation control needs an assembly design; a fixed foam thickness cannot guarantee that condensation will never occur. ## What Determines the Quote for Each Foam The two foams are quoted the same way: square footage of the surface, the specified depth, access, and what has to happen before and after the spray. Depth is the big variable: a roof deck specified to Zone 1 R-30 in open cell is a very different quantity of material from a block wall furred for two inches of closed cell. Removing old blown-in or batts, repairing a deck, sealing soffits, adding an ignition-barrier coating, and splitting the house into a closed-cell envelope with open-cell interiors each change the scope. We price every job in writing from the address or a plan set, without a site visit, so you can compare the two foams for your actual house rather than for a hypothetical one. ### What to Expect After Installation Energy savings depend on the home's starting condition and the complete work scope. ENERGY STAR's published savings estimates model combined air sealing and insulation improvements; they are not a guarantee for switching to spray foam. For your project, agree on the installed scope and document the completed work. Comparing bills also requires accounting for weather, occupancy and thermostat settings. Want a real number for your house? We size the job from your county property-appraiser record and send you a written price — no site visit needed. Call (239) 455-2002 or email estimates@idealinsulationinc.com. ## R-Value Requirements and Comparison ### R-Value by Thickness: Product Examples These are selected data points for the Carlisle open-cell and closed-cell products identified above. Use a manufacturer's published thickness table for an actual specification; do not fill missing values by assuming a universal per-inch number. | Thickness | Open Cell R-Value | Closed Cell R-Value | | --- | --- | --- | | 1 inch | R-3.7 | R-6.9 | | 3 inches | See product data | R-21 | | 3.5 inches | R-13 | See product data | ### Florida Building Code Requirements The 2023 Florida residential R-value prescriptive form lists ceiling R-30 in Climate Zone 1 and R-38 in Zone 2, with wood-frame wall R-13 in both. These values belong to that compliance method and its scope and footnotes; they are not a universal specification for every retrofit or assembly. Use the permitted project's approved energy calculations and plans. Framing depth alone does not create an R-20 wall requirement, and air sealing does not automatically replace a required insulation R-value. ### Why R-Value Is Not the Whole Story R-value measures resistance to heat flow. The finished building also depends on insulation coverage, air leakage and the other parts of its enclosure. Compare complete assemblies rather than promising that a lower-R wall always outperforms a higher-R wall. ## Moisture Control and Vapor Retarders Vapor permeance describes how readily water vapor passes through a material. Open-cell and closed-cell products differ, and the value changes with product and thickness. Air leakage, rainwater and vapor diffusion are separate moisture paths. Plan the water, air and vapor-control layers together so the wall or roof can manage moisture and dry as intended. Lower vapor permeance does not guarantee a mold-free or condensation-free assembly. Before spraying, check the substrate condition and any existing leaks. Do not cover a moisture problem with insulation and assume it has been resolved. ## Structural and Hurricane Claims Some closed-cell products have tested assembly benefits, but that is not a blanket structural rating. For example, Carlisle's closed-cell data sheet describes structural enhancement while classifying the product as nonstructural insulation. Any structural use must be supported by the exact product and assembly documentation and accepted in the project design. Foam does not replace required roof attachments, connections, opening protection or water-control details. ### Technical References For project planning, see the [DOE Energy Saver guide](https://www.energy.gov/sites/default/files/2022-08/energy-saver-guide-2022.pdf), [PNNL's unvented-attic guidance](https://basc.pnnl.gov/resource-guides/unvented-conditioned-attic-spray-foam-insulation-below-roof-deck), [PNNL's flood-resistant crawlspace guidance](https://basc.pnnl.gov/resource-guides/flood-resistant-crawlspace-foundations), the [Florida R402-2023 form](https://www.floridabuilding.org/fbc/committees/energy/energy_forms/2023_Energy_Forms/Form_R402-2023.pdf), and the [Carlisle open-cell](https://www.carlislesfi.com/wp-content/uploads/613317-CSFI-10151-SealTite-PRO-Open-Cell-TDS-06-25-21-1.pdf) and [closed-cell product data sheets](https://dam.henry.com/m/54100613cbd9de5f/original/613302-CSFI-10140-SealTite-PRO-Closed-Cell-TDS.pdf). Product examples are not a statement that these products are selected for your job. ## Frequently Asked Questions Which is better for a Florida attic, open cell or closed cell spray foam? Either can be used under a Florida roof deck. Open cell is sprayed to full rafter depth and left vapor-open so the deck can dry inward; closed cell is sprayed thinner and is chosen for metal roofs or where the designer wants the foam to be the vapor retarder. The decision comes from the required ceiling R-value on the permit (R-30 in Climate Zone 1, R-38 in Zone 2 under the 2023 Florida prescriptive table), the available rafter depth and the product's published thickness table. No open-cell product has a universal five-inch R-30 rating. Do I need a vapor barrier with spray foam in Florida? Not an interior one. In Climate Zone 1 and 2 the vapor drive is from outside to inside for most of the year, so an interior polyethylene or foil sheet creates a condensation plane. If the assembly needs a vapor retarder, closed-cell foam at the right depth is it: the referenced product is rated 0.8 perms at one inch, a Class II retarder. Open cell is vapor-open (21 perms at one inch) and relies on the assembly drying inward. Can open cell spray foam be used on a roof deck in Florida? Yes, in an unvented attic assembly that follows the manufacturer's application guide and PNNL's unvented-attic guidance: sprayed to the depth that reaches the required R-value, with the roof kept watertight and the attic dehumidified or conditioned. It is not the right choice directly against a metal roof panel, where closed cell controls condensation. Is open cell or closed cell spray foam better for soundproofing? Open cell absorbs more sound because of its soft, open structure, which is why it is used in interior partitions. The sound rating of a finished wall depends on framing, finishes and penetrations, so compare tested wall assemblies rather than foam type alone. Does spray foam make a house stronger in a hurricane? Do not count on it. Closed-cell product data sheets describe structural enhancement while classifying the foam as nonstructural insulation. Any contribution to wind resistance has to be documented for the exact product and assembly and accepted in the project design. Foam is not a substitute for required structural connections, roof-to-wall straps or opening protection. Do I need a thermal barrier or ignition barrier over spray foam? Yes. Both foam types must be separated from occupied space by a code-prescribed 15-minute thermal barrier such as half-inch gypsum board, or by a tested alternative such as an approved intumescent coating. Attics and crawl spaces entered only for service may use an ignition barrier or a coating approved under ICC-ES AC377 Appendix X, or a product-specific exemption. Which one applies should be written into the scope before the job. Can I use closed cell and open cell in the same house? Yes, and in custom homes it is the normal outcome: closed cell on the exterior envelope, block walls, metal surfaces and elevated floors, with open cell on roof decks that have the depth and on interior partitions for sound. The split is decided by the assembly, not by a rule of thumb. Can I use open cell spray foam in a crawl space or under an elevated floor? Usually not the first choice. Suitability depends on the product approval, moisture conditions and any flood requirements. PNNL's flood-resistant crawlspace guidance is built around a specified closed-cell assembly, and even that assembly requires cleaning the exposed foam after floodwater contact. Address drainage and ground moisture first; foam alone does not make a crawl space dry. ## Why Professional Installation Matters Spray foam installation needs trained applicators, appropriate equipment and the selected product's instructions. Quality checks should address mixing, substrate conditions, thickness, adhesion and any required protective covering. Plan ventilation and access restrictions before work begins. Follow the manufacturer for re-entry and re-occupancy requirements. Professional installation reduces avoidable risks; it does not eliminate every possible defect or exposure. ## Get Your Free Spray Foam Assessment Ready to upgrade your home's insulation? Whether you're building a new custom home or improving an existing property in Naples, Fort Myers, Cape Coral, Bonita Springs, or anywhere in Southwest Florida, our team can help you determine the right spray foam solution for your specific situation. **What to expect when you contact us:** - A written price sized from your county property-appraiser record — no site visit needed - A recommendation based on your house, your budget and how you use it - A free pre-visit before we install, so there are no surprises on install day - Confirmation of the installation team and scope before work begins - An installation date confirmed for your project - Online payment or ACH, no surcharge. Se habla español. [Call (239) 455-2002 for a written price](tel:2394552002) Or email [estimates@idealinsulationinc.com](mailto:estimates@idealinsulationinc.com), or [send us the address here](https://www.idealinsulationinc.com/contact-us-ideal-insulation). Se habla español. Ideal Insulation Enterprises serves Southwest Florida including Naples, Fort Myers, Cape Coral, Bonita Springs, Estero, Marco Island and Lehigh Acres, plus Punta Gorda and Port Charlotte in Charlotte County. We specialize in spray foam insulation for new construction custom homes and retrofit applications. --- ### See Where the Attic Is Leaking Before You Choose a Foam Ask for the thermal-imaging scan with your estimate. It shows where the attic is leaking conditioned air before anyone picks a foam. We serve Naples, Fort Myers, Bonita Springs, Marco Island, and all of Southwest Florida. **[Schedule Your Free Energy Audit →](https://www.idealinsulationinc.com/free-energy-audit)** ### Related Insulation Resources - → [Spray Foam Insulation in Naples FL](https://www.idealinsulationinc.com/insulation-blog/spray-foam-insulation-naples-fl) - → [What Goes Into a Spray-Foam Quote in Naples](https://www.idealinsulationinc.com/insulation-blog/spray-foam-insulation-cost-in-naples-fl-2026-price-guide) - → [Is Spray Foam Worth It in Florida?](https://www.idealinsulationinc.com/insulation-blog/is-spray-foam-insulation-worth-it-florida) - → [Spray Foam and Hurricane Considerations](https://www.idealinsulationinc.com/insulation-blog/hurricane-proof-your-naples-home-the-overlooked-role-of-spray-foam-insulation) - → [Spray Foam Services](https://www.idealinsulationinc.com/services/spray-foam-insulation-naples-fl) --- ### Get a Written Price for Either Foam, or Both [**Ideal Insulation**](https://www.idealinsulationinc.com) is a Naples-based insulation contractor serving Naples, Fort Myers, Cape Coral and Bonita Springs since 2013. Whether you need [spray foam insulation](https://www.idealinsulationinc.com/services/spray-foam-insulation-naples-fl), [blown-in attic insulation](https://www.idealinsulationinc.com/blown-in-insulation-naples-swfl/), or a complete insulation upgrade, contact us to discuss the scope and available installation dates. Building or renovating in Southwest Florida? Talk to our [**closed-cell spray foam for luxury & custom homes**](https://www.idealinsulationinc.com/services/luxury-home-insulation-naples-fl) for a free consultation and estimate. **[Schedule your free thermal leak scan](https://www.idealinsulationinc.com/free-energy-audit)** or call **(239) 455-2002** today. Put the guide to work ## Get an estimate for your property Send the address, project details and any plans or photos. We can discuss the insulation scope, existing conditions and scheduling. [Request an Estimate](https://clienthub.getjobber.com/hubs/d0e0f91b-8c25-49dd-9fb4-6813040a7759/public/requests/4221726/new)[Call (239) 455-2002](tel:+12394552002) [Spray foam options in Naples](https://www.idealinsulationinc.com/services/spray-foam-insulation-naples-fl) · [Builder bids and plan review](https://www.idealinsulationinc.com/insulation-contractor-for-builders-naples-fl-swfl) Prefer email? 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Foam is not a substitute for required structural connections, roof-to-wall straps or opening protection." }, "name" : "Does spray foam make a house stronger in a hurricane?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Yes. Both foam types must be separated from occupied space by a code-prescribed 15-minute thermal barrier such as half-inch gypsum board, or by a tested alternative such as an approved intumescent coating. Attics and crawl spaces entered only for service may use an ignition barrier or a coating approved under ICC-ES AC377 Appendix X, or a product-specific exemption. Which one applies should be written into the scope before the job." }, "name" : "Do I need a thermal barrier or ignition barrier over spray foam?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Yes, and in custom homes it is the normal outcome: closed cell on the exterior envelope, block walls, metal surfaces and elevated floors, with open cell on roof decks that have the depth and on interior partitions for sound. The split is decided by the assembly, not by a rule of thumb." }, "name" : "Can I use closed cell and open cell in the same house?" }, { "@type" : "Question", "acceptedAnswer" : { "@type" : "Answer", "text" : "Usually not the first choice. Suitability depends on the product approval, moisture conditions and any flood requirements. PNNL's flood-resistant crawlspace guidance is built around a specified closed-cell assembly, and even that assembly requires cleaning the exposed foam after floodwater contact. Address drainage and ground moisture first; foam alone does not make a crawl space dry." }, "name" : "Can I use open cell spray foam in a crawl space or under an elevated floor?" } ] } ```