Nudura Insulated Concrete Form walls typically deliver an R-value starting at 23.59, based on standard theoretical values published in the ASHRAE Handbook, with even higher R-values available through Nudura’s Plus Series products. By comparison, typical wood-frame structures range from just R-11 to R-19, according to the ICFMA Thermal Study. This performance comes from continuous EPS foam insulation on both sides of the concrete core, combined with high thermal mass. The result is a building envelope with decreased thermal conductivity that resists temperature fluctuations and air leakage. Click here to learn more about R-value and thermal mass.
ICFs contribute to lower HVAC sizing and operating costs by stabilizing interior temperatures and reducing the load on mechanical heating and cooling equipment. The high thermal mass of the concrete core delays internal temperature swings as outdoor conditions change, creating a largely self-regulating environment. Independent testing by CLEB Laboratories (ASTM C1363-11) found that an ICF wall can achieve up to 60% annual energy savings compared to a 2"x6" wood-frame wall. Less HVAC runtime translates to significantly lower utility bills over the life of the building.
Thermal bridging differs significantly because ICF walls provide continuous insulation with no repeating conductive members, while steel stud walls create frequent thermal bridges at every metal stud. Steel is highly conductive, so each stud becomes a path for heat to escape unless mitigated with exterior continuous insulation. Nudura ICFs place EPS foam continuously on both the interior and exterior of the concrete core, eliminating the cold spots and drafts associated with framed wall systems.
You attach siding or stucco to ICF using the built-in fastening strips embedded in every Nudura block, located every 8 inches (203 mm). These strips let you securely anchor exterior finishes, including siding, brick, stucco, EIFS and exterior panels directly to the wall without additional furring. Nudura ICFs can accommodate virtually any exterior finish, giving architects and builders broad design flexibility.
Fastening options for heavy exterior claddings begin with the embedded fastening strips spaced every 8 inches, and for masonry veneers, brick ledge form units are available to carry the load. Nudura offers brick ledge and brick ledge extension form units (Appendix A, details A-6 and A-7) plus brick veneer angle details for multi-story applications. For heavy claddings, connections should be engineered to transfer load to the concrete core.
Interior drywall attaches directly to the fastening strips embedded every 8 inches (203 mm) within each Nudura ICF block. These strips provide a secure, code-recognized anchoring surface, so drywall can be screwed on without additional framing or strapping. This built-in finish anchorage is one of the six building elements Nudura combines into a single form.
Foam concrete forms significantly improve building airtightness because an air barrier is built into the Nudura ICF assembly, thanks to the permeance levels of the EPS foam and the monolithic concrete core. Nudura's DURALOCK™ technology mechanically links each block to prevent air leakage through the assembly. Reduced air leakage is a core reason ICF buildings achieve high energy efficiency and stable interior comfort.
ICF walls help with moisture control because a vapor barrier comes built into the Nudura form system, helping prevent moisture infiltration and mold within the wall cavity. Combined with the built-in air barrier, this reduces the pathways through which moisture-laden air can enter the assembly.
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