Polystyrene panels that can be slipped inside insulated concrete forms (ICFs)
Reward Wall System, a manufacturer of insulated concrete forms (ICFs), is now selling polystyrene panels that can be slipped inside ICFs to improve a wall’s R-value. This product will prove useful because most ICFs have a relatively low R-value. (According to tests conducted by Oak Ridge National Laboratory, the clear-wall R-value for the typical ICF wall is about R-12.)
Called Boost-R panels, these new foam rectangles come with notches that slide over the ICF form ties and rebar chairs. Of course, these Boost-R panels take up room that normally would be filled with concrete. If you want to use these insulation inserts, you’ll need to order ICFs that have thicker-than-usual cores. If you ordinarily use ICFs with a 6-in.-thick concrete core and plan to add an extra 4 in. of foam on one side of the wall, then you’ll need ICFs with a 10-in. core.
Boost-R panels are 2 in. thick and are available in several different densities (1 lb., 1-1⁄2 lb., and 2 lb. per cu. ft.). If you want more than 2 in. of extra insulation, it’s possible to insert two layers of 2-in.-thick Boost-R panels inside the core of a thick ICF.
The manufacturer claims that its 1-1⁄2-lb.-per-cu.-ft. polystyrene has an R-value of R-4.17 per in. Thus, a 15-in. ICF with a 10-in.-thick core equipped with a 4-in.-thick Boost-R panel will be R-38.
Two-in.-thick Boost-R panels cost between 95¢ and $1.85 per sq. ft., depending on the foam density and the quantity ordered. Of course, there is a simpler way to obtain ICFs with a higher R-value: Order them from Logix, one of Reward Wall System’s competitors. Logix’s XRV line of ICFs is available in a variety of sizes, with R-values up to R-66.