Icynene Boosts R-Value of Spray-Foam Insulation
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 the two-part spray-in insulation has an R-value of 4 per in., compared to the 3.7 per in. of its Classic and Classic Max open-cell 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 in., meaning 2×6 wall cavities would have a total R-value of 20.35.
That’s enough to meet the International Code Council’s 2012 energy requirements, as explained in a blog by GreenBuildingAdvisor senior editor Martin Holladay. Builders need at least R-21 in wall cavities in climate zones 7 and 8 in order to meet the 2009 energy code (lower in other, more moderate climate zones). The 2012 energy code only calls for R-20 in wall cavities, but it adds a requirement for continuous insulation on the outside of the walls to reduce thermal bridging (R-5). Icynene says some jurisdictions have amended the 2012 code to require R-21 in the wall cavities because it’s cheaper than cavity insulation plus outside insulation. Standard open-cell foam is rated at only R-3.7 per in., making a 2×6 framed wall less than R-21.
“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 email.
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.