Icynene is now offering a low-density polyurethane foam insulation with a slightly higher R-value, which the company says will help builders meet stricter energy code requirements.

The product is called Icynene Classic Plus. The manufacturer says that the two-part spray foam insulation has an R-value of 4 per inch, compared to R-3.7 per inch for its Classic and Classic Max open-cell foam products.

Sprayed into a 2×6 wall, the foam would provide a total of R-22 in stud cavities. (Whole-wall R-values would be lower because of thermal bridging at wall studs, headers, and other framing members.) The company’s other low-density polyurethane foams have R-values of 3.7 per inch, meaning that 2×6 wall cavities with these older formulations would have a total R-value of 20.35.

The new product that attains R-22 has a high enough R-value to meet the International Code Council’s 2012 energy requirements (explained in a blog by GBA senior editor Martin Holladay). But Icynene said that most states are using the 2009 energy code, which requires R-21 in Climate Zones 7 and 8, and some jurisdictions that have adopted the 2012 requirements have modified it so that it, too, calls for R-21 in wall cavities.

“We initially developed the Classic Plus to meet the 2009 code, but have seen other climate zones adopt the R-21 value as well, so we can satisfy all areas in the country that require R-21 (even R-22) in 2×6 wood stud walls,” a company spokesman said by e-mail.

Like other open-cell polyurethane foams, Classic Plus is vapor-permeable. But it has slightly higher density than other Icynene open-cell products, 0.7 lb. per cubic foot (pcf) vs. 0.5 pcf. It’s also water-blown, so it has minimal global warming potential, Icynene says.