Spray Foam Insulation for Architects and Specifiers
Spec it in one sitting.
R-25 at 3.5 inches. 0.45 perms at 2 inches. No ignition barrier coating in service-only attics. GWP of 1. Two products, every number tested to an ASTM method, every report one click away.
Built to survive plan review
Assemblies that pass
Both products carry Class I flame spread and smoke index (ASTM E84), with defined thermal and ignition barrier paths per NFPA 286 and ICC-ES AC377 Appendix X — and ComfortSeal HFO needs no ignition barrier coating in service-only attics and crawl spaces, within the report's thickness limits.
Vapor control by design
Choose your permeance: closed cell at 0.45 perms at 2 inches acts as the vapor retarder in exterior and high-humidity assemblies, while open cell at 21 perms at 1 inch stays vapor-open for assemblies that dry to the interior.
Sustainability you can cite
An HFO blowing agent with a global warming potential of 1 on the closed cell, and fully water-blown open cell — numbers you can cite in green-building documentation.
Key properties, side by side
Values from the current technical data sheets and IAPMO evaluation reports. Full data sheets with liquid component properties and processing parameters are in the tech library.
| Property | ComfortSeal 500 · Open Cell | ComfortSeal HFO · Closed Cell | Test method |
|---|---|---|---|
| R-value at 3.5 in. (2x4) | R-13 | R-25 | IAPMO Table 1 |
| R-value at 5.5 in. (2x6) | R-20 | R-39 | IAPMO Table 1 |
| R-value per inch | 4.1 at 1 in., falling to 3.5–3.7 at 3.5–14 in. | 7.3 at 1 in., falling to 7.0–7.1 at 3.5–12 in. | ASTM C518; IAPMO Table 1 |
| Core density | 0.5 lb/ft³ | 2.0 lb/ft³ | ASTM D1622 |
| Cell content | >97% open | >92% closed | ASTM D6226 / D2856 |
| Water vapor permeance | 21 perms @ 1" | 0.45 perms @ 2" (Class II vapor retarder) | ASTM E96 |
| Air leakage rate | <0.002 L/s·m² | — | ASTM E283 |
| Compressive strength | — | 29.5 PSI | ASTM D1621 |
| Tensile strength | 5.19 PSI | 56.8 PSI | ASTM D1623 |
| Water absorption | — | 1.44% change | ASTM D2842 |
| Dimensional stability | <5% | 6.5% | ASTM D2126 |
| Sound — NRC / STC | 0.75 / 39 | — | ASTM C423 / E413 |
| Flame spread & smoke | Class I (≤25 / ≤450) | Class I (≤25 / ≤450) | ASTM E84 |
| Ignition barrier | Pass with DC315 or No-Burn Plus ThB coating | No coating in service-only attics & crawl spaces | ICC-ES AC377 App. X |
| Wind uplift resistance | — | 210 psf | UL 1897 |
| Fungi resistance | — | No growth | ASTM G21 |
| Blowing agent | Water | HFO, global warming potential of 1 | Data sheet |
| Evaluation report | ER-974 (opens in new tab) | ER-975 (opens in new tab) | IAPMO UES |
The R-value per inch of this insulation varies with thickness. The thicker the insulation, the lower the R-value per inch. The higher the R-value, the greater the insulating power. Ask your seller for the fact sheet on R-values. R-values by thickness and per-inch ranges are from IAPMO ER-974 and ER-975, Table 1.
Values current as of the Rev. 09/2026 technical data sheets and subject to change — always verify against the current data sheet before specifying. Coating thicknesses for the ignition and thermal barrier results are in the fire performance table below.
Barrier results, with coating thicknesses
A Class I surface burning rating does not by itself mean foam can be left exposed. Here are the ignition and thermal barrier results, with the coating thicknesses tested.
| Result | ComfortSeal 500 · Open Cell | ComfortSeal HFO · Closed Cell | Test method |
|---|---|---|---|
| Ignition barrier (attics & crawl spaces) | Pass with DC315 at 6 wet / 4 dry mils or No-Burn Plus ThB at 4 wet / 3 dry mils | No coating in service-only attics & crawl spaces (up to 10 in. roof deck, 6 in. walls) | ICC-ES AC377 App. X |
| Thermal barrier (exposed foam) | Pass with DC315 at 18 wet / 12 dry mils | Passed 15 minutes with DC315 or No-Burn Plus ThB at 14 wet / 9 dry mils | NFPA 286 |
Codes generally require a thermal barrier between foam plastic and occupied space, typically half-inch gypsum wallboard; the NFPA 286 results are the tested-coating alternative. The authority having jurisdiction decides which path applies. See our ignition vs. thermal barrier guide.
Scope of the evaluation reports. ER-974 and ER-975 recognize both products for Type V construction under the IBC and one- and two-family dwellings under the IRC, under the 2021, 2018 and 2015 IBC, IRC and IECC and the 2023 Florida Building Code. The coating listings carry maximum foam thicknesses: for ComfortSeal 500, 8 in. on walls and 14 in. on ceilings with the DC315 thermal barrier; for ComfortSeal HFO, 5.5 in. on walls and 9.5 in. on ceilings with DC315, or 7 in. and 10 in. with No-Burn Plus ThB. Neither report covers NFPA 285 or other construction types, and ComfortSeal HFO is not for contact with soil or standing water.
Specify R-value from the report table
R-value per inch is for comparing materials. A specification should quote the report value at the installed thickness; the tables are not linear, so multiplying per-inch R by inches overstates the result.
| Installed thickness | ComfortSeal 500 · R-value | ComfortSeal HFO · R-value | Source |
|---|---|---|---|
| 1 inch | R-4.1 | R-7.3 | IAPMO ER-974 (opens in new tab) / ER-975 (opens in new tab), Table 1 |
| 3.5 inches (2x4 cavity depth) | R-13 | R-25 | IAPMO ER-974 / ER-975, Table 1 |
| 4 inches | R-14 | R-28 | IAPMO ER-974 / ER-975, Table 1 |
| 5.5 inches (2x6 cavity depth) | R-20 | R-39 | IAPMO ER-974 / ER-975, Table 1 |
Both tables continue to greater thicknesses: ER-974 lists ComfortSeal 500 up to R-51 at 14 inches, and ER-975 lists ComfortSeal HFO up to R-84 at 12 inches. Use the R-value calculator or our R-value by thickness guide to read the right row for either product.
What to call out in the spec
Leave nothing to interpretation. Adapt these to your format and confirm code requirements with the authority having jurisdiction.
Product and report
Name the product — ComfortSeal 500 open cell or ComfortSeal HFO closed cell — and cite its IAPMO UES report (ER-974 or ER-975), which sets the conditions of use the reviewer will check.
Thickness and R-value by location
Give the installed thickness for each assembly and the R-value the report table lists at that thickness — for example, R-39 at 5.5 inches of ComfortSeal HFO.
Vapor control
Where the foam is the vapor retarder, specify ComfortSeal HFO at no less than 2 inches, the thickness at which its 0.45-perm Class II result was measured. ComfortSeal 500 is vapor-open (21 perms at 1 inch), so detail vapor control separately where the climate calls for it.
Barrier by location
For each space, state the thermal or ignition barrier: a prescriptive barrier, or a coating listed for that product and barrier type at the thickness in its evaluation report (for ComfortSeal 500 thermal barriers, DC315 only).
Substrate and site conditions
Reference the data sheet limits: substrate moisture below 18%, and substrate and ambient above 32°F for ComfortSeal 500, or above 45°F in summer and 14°F in winter for ComfortSeal HFO.
Installer qualification
Require a certified ComfortSeal installer — also the condition of the limited lifetime warranty on the foam, for the life of the home.
Detailing a specific assembly? See our guides to unvented attics, humid and coastal climates and how to read a data sheet, or ask our team.
Everything plan review asks for
No chasing a manufacturer for test data at 4pm before a submittal deadline. Download what you need, or ask our team for anything you don't see.
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Asked at the drafting table
Does ComfortSeal need an ignition barrier in attics and crawl spaces?+
ComfortSeal HFO closed cell is recognized for installation in service-only attics and crawl spaces with no ignition barrier coating, up to 10 inches on the roof deck and 6 inches on walls, per ICC-ES AC377 Appendix X and evaluation report ER-975. ComfortSeal 500 open cell passes with DC315 at 6 wet mils or No-Burn Plus ThB at 4 wet mils (IAPMO ER-974 Table 5).
How should I handle vapor control between the two products?+
ComfortSeal HFO measures 0.45 perms at 2 inches (ASTM E96) and serves as the vapor retarder in exterior and high-humidity assemblies. ComfortSeal 500 measures 21 perms at 1 inch and stays vapor-open — the right choice where the assembly is designed to dry to the interior.
What documentation supports a submittal?+
Technical data sheets with ASTM methods for every value, evaluation reports ER-974 and ER-975, Class I fire data (ASTM E84), and thermal/ignition barrier compliance paths (NFPA 286, ICC-ES AC377 Appendix X). Start in the tech library.
What can I cite for sustainability documentation?+
ComfortSeal HFO's blowing agent has a global warming potential of 1, and ComfortSeal 500 is fully water blown. Both figures come straight from the technical data sheets.
What R-value should I specify for a given thickness?+
Use the evaluation report table, not a per-inch figure multiplied by thickness. ER-975 lists ComfortSeal HFO at R-25 at 3.5 inches, R-28 at 4 inches and R-39 at 5.5 inches. ComfortSeal 500 values by thickness are in ER-974; the R-value calculator reads either table.
Can ComfortSeal be left exposed in occupied space?+
Only behind a thermal barrier or an approved alternative. Under NFPA 286, ComfortSeal 500 passed with DC315 at 18 wet / 12 dry mils, and ComfortSeal HFO passed 15 minutes with DC315 or No-Burn Plus ThB at 14 wet / 9 dry mils. Confirm the path with the authority having jurisdiction.
Who installs ComfortSeal, and what does the warranty cover?+
Certified ComfortSeal installers. Installs by certified ComfortSeal installers carry a limited lifetime warranty on the foam, for the life of the home. Installation workmanship is the installing contractor's responsibility; certified installation is a condition of coverage. The full written terms are being finalized; ask our team and we'll walk you through what's covered.
Put ComfortSeal in the spec book
Pull the documents now, or talk to our team about an assembly you're detailing.