THERMAX™ (ci) Exterior Insulation
A system in itself- providing continuous insulation value, fire
resistance and an integral drainage plane – THERMAX™ (ci)
Exterior Insulation is the key component of the THERMAX™
Wall System.

THERMAX™ (ci) Exterior Insulation helps U.S. commercial building owners meet the ASHRAE prescriptive continuous insulation requirement. It is also a key component of the THERMAX™ Wall System.

The integral, durable facer of THERMAX™ (ci) Exterior Insulation provides a drainage plane and water-resistive barrier, eliminating the extra step of installing a membrane or building wrap. The lightweight polyisocyanurate foam core provides one of the highest R-values available (R-6.5 at 1") for long-term thermal performance.

For best results, seal joints with WEATHERMATE™ Straight Flashing.

Building Code Compliance

Complies with ASTM C1289 Type I, Class 2. Meets IBC/IRC requirements for foam plastic insulation. See ICC-ES ESR-1659. FM 4880 - see Factory Mutual Approval Guide. UL Classified, see Classification Certificate 1256. Calif. Std. Reg. # CA T383.

Related Information

THERMAX™ (ci) Exterior Insulation Product Information (61KB PDF)
Making History: THERMAX™ Exterior Insulation at The H (513KB PDF)

Nominal Board Thickness(1), in R-Value(2)(3) Board Size, ft Edge Treatment Min Compressive Strength(4), psi
.625 4.1 4' x 8' / 4' x 12' Square Edge 25
1.0 6.5 4' x 8' / 4' x 12' Square Edge 25
1.55 10.1 4' x 8' / 4' x 12' Shiplap 25
2.0 13.0 4' x 8' / 4' x 12' Shiplap 25

For requests and inquiries regarding 3” widths please contact our Building Envelope Specialists.

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(1) Not all product sizes are available in all regions.

(2) R means resistance to heat flow. The higher the R-value, the greater the insulating power. R-values are expressed in ft2• h•°F/Btu. R-value determined by ASTM C518.

(3) Consult your Dow Seller or Technical Service Group for information on different R-values.

(4) Vertical compressive strength is measured at 10% deformation or yield, whichever occurs first. Since Dow polyisocyanurate insulation is a visco-elastic material, adequate design safety factors should be used to prevent long-term creep. For static loads, 3:1 is suggested. For dynamic loads, 5:1 is suggested.