Can builders achieve R-38 using 5.5-inch X-Brackets filled with closed-cell spray foam?

Builders can achieve R-38 using 5.5-inch InSoFast X-Brackets filled with closed-cell spray foam, which yields R-30 to R-38 by securing 5.5 inches of high-density foam rated at R-6 to R-7 per inch.

Meeting high thermal envelope standards in exterior walls and roofs often creates framing depth challenges. Thick stud framing causes significant thermal bridging through solid wood or steel studs, reducing total effective insulation value unless a fully continuous thermal break spans across the assembly.

If you only do one thing: Specify closed-cell polyurethane foam rated at R-6.9 to R-7.0 per inch and apply it to the full 5.5-inch bracket depth to reach the maximum R-38 thermal rating.

• System R-value ratings: The 5.5-inch X-Bracket delivers an assembly rating of R-30 to R-38 when filled with 2.0 lb/cu ft closed-cell spray foam, compared to R-21.5 with dense-packed blown insulation.
• Thermal bridge reduction: The non-conductive composite brackets reduce thermal conductivity by a factor of 250 compared to standard steel fasteners, eliminating direct thermal bridging across the envelope.
• Box coverage: One carton covers approximately 77 to 97 square feet at 16-inch on-center spacing, or 116 to 136 square feet at 24-inch on-center spacing on walls, roofs, basements, and shipping containers.
• Structural capacity: The bracket assembly is engineered to support exterior claddings, tested to lateral loads exceeding 300 pounds per square foot and wind resistance exceeding 200 miles per hour.
• Multi-barrier performance: A full 5.5-inch installation of closed-cell foam creates a monolithic air barrier and vapor retarder directly over masonry, concrete, or framed substrates.

• Watch out for: Spraying single foam lifts thicker than 2 inches per pass, which generates internal exothermic heat buildup, charring, and shrinkage away from bracket surfaces.
• Watch out for: Foam overfilling past the 5.5-inch bracket profile, requiring time-consuming mechanical rasping before fastening exterior rainscreen siding or interior wallboard.
• Watch out for: Substituting open-cell spray foam in the 5.5-inch bracket cavity, which only delivers R-19 to R-21 and fails to provide moisture-impermeable vapor control.

Calculate your total project square footage and contact InSoFast technical support at (888) 501-7899 to verify bracket counts and lift schedules for your target R-value.