Closed Cell Spray Foam

ThermoSeal HFO

Next-generation closed cell spray foam with R-7.4 per inch, the highest available. HFO blown using Forane 1233zd with a GWP of 1. No ignition barrier required. Wind uplift rated to 286 mph.

Closed CellR-7.4/inchGWP 1 (HFO)286 MPH Wind UpliftNo Ignition BarrierIAPMO ER-0698

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R-7.4

Per Inch (ASTM C 518)

286

MPH Wind Uplift

GWP 1

Forane 1233zd

2.0 lb

Core Density (ft³)

Technical Specifications

ThermoSeal HFO Physical Properties

All values independently tested per ASTM standards. Full technical data sheet available for download.

Physical Properties (ASTM Tested)
R-Value	7.4 @ 1" / 25.9 @ 3.5"	ASTM C 518
Core Density	1.9 – 2.1 lb/ft³	ASTM D 1622
Closed Cell Content	≥ 92%	ASTM D 2856
Air Permeance	<0.02 L/sm² @ 75 Pa / 2.0"	ASTM E 283 & E 2178
Water Vapor Permeance	0.86 Perms @ 1.37"	ASTM E 96
Compressive Strength	27.43 PSI	ASTM D 1621
Tensile Strength	48.64 PSI	ASTM D 1623
Wind Uplift	PASS @ 210 psf / 286 mph	UL 1897
Fortified Roofs	PASS @ 171.6 psf	ASTM E 330
Flame Spread Index	< 25 (Class 1)	ASTM E 84
Dimensional Stability	< 2%	ASTM D 2126

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Certifications & Compliance

Code Approvals

IAPMO ER-0698

Closed cell spray foam for residential and commercial applications per IRC/IBC/IECC.

UL 1897: 286 MPH Wind Uplift

PASS at 210 psf, equivalent to 286 mph sustained wind. Approved for Fortified Roof designation.

No Ignition Barrier

Approved for use in attics and crawlspaces without an additional ignition barrier per IAPMO ER-0698 assembly listings.

Class II Vapor Retarder

Water vapor permeance of 0.86 perms at 1.37 inches, which meets Class II vapor retarder requirements per IRC/IBC.

Other ThermoSeal Products

ThermoSeal 500

Open cell, R-4.1/inch, GWP 1

ThermoSeal 800

Open cell, R-4.5/inch, enhanced density

ThermoSeal 5G

Closed cell, commercial grade, NFPA 285

Where to Use It

ThermoSeal HFO Applications

Recommended applications for ThermoSeal HFO based on climate zone, building type, and performance requirements.

Roofdecks: All Climate Zones

Applied to the underside of roof sheathing, ThermoSeal HFO creates a sealed conditioned attic. At 3.5 inches, R-25.9. No ignition barrier required. Wind uplift rated to 286 mph.

Crawlspaces

Closed cell structure prevents moisture vapor transmission from soil. Applied to crawlspace walls and slab perimeter at 2–3 inches, creating a fully conditioned, moisture-resistant crawlspace.

Rim Joists

At 2–3 inches, ThermoSeal HFO delivers R-14.8 to R-22.2 in the rim joist cavity, the highest R-value achievable in this space-constrained location.

Exterior Walls: Cold Climates

For climate zones 5–8, closed cell foam on the exterior side of the stud wall prevents interstitial condensation while delivering high R-values in shallow cavities.

Metal Buildings

Eliminates thermal bridging at steel framing members and prevents condensation on metal surfaces. Adds measurable structural racking resistance.

Hurricane & Storm Zones

286 mph wind uplift rating and fortified roof approval make ThermoSeal HFO the specification of choice in coastal and high-wind markets.

Common Questions

ThermoSeal HFO FAQ

What is the R-value of ThermoSeal HFO?

ThermoSeal HFO delivers R-7.4 per inch per ASTM C 518, the highest R-value per inch of any product in the ThermoSeal lineup. At 3.5 inches, the installed R-value is R-25.9. At 2 inches (rim joist application), R-14.8.

What blowing agent does ThermoSeal HFO use?

ThermoSeal HFO uses Forane 1233zd LBA, a hydrofluoroolefin (HFO) blowing agent with a Global Warming Potential (GWP) of 1. This is 99.9% lower than the HFC blowing agents (GWP ~1,030) used in older closed cell foam products. It contains zero ozone depleting substances.

Does ThermoSeal HFO require an ignition barrier?

No. ThermoSeal HFO is approved for use in attics and crawlspaces without an additional ignition barrier, per the assembly listings in IAPMO Evaluation Report ER-0698. This is a significant installation advantage versus products that require a thermal or ignition barrier.

What is the wind uplift rating of ThermoSeal HFO?

ThermoSeal HFO passes UL 1897 at 210 psf, equivalent to a sustained wind speed of 286 mph. It is also approved for Fortified Roof designation, passing ASTM E 330 at 171.6 psf. This makes it a strong specification for coastal markets, hurricane zones, and high-wind areas.

Can ThermoSeal HFO act as a vapor barrier?

Yes. At 1.37 inches, ThermoSeal HFO has a water vapor permeance of 0.86 perms, qualifying it as a Class II vapor retarder per IRC and IBC. At greater thickness, permeance decreases further. This eliminates the need for a separate vapor barrier in most assemblies.