Dow Thermax Sheathing
THERMAX™ Sheathing is a nonstructural,rigid board insulation with a glass-fiber-infused polyisocyanurate foam core laminated between 1.0 mil smooth, reflective aluminum faces. The glass-fiber reinforcement provides improved fire performance and dimensional stability. THERMAX™ Sheathing can be installed exposed to the interior without a thermal barrier. THERMAX™ Sheathing offers high, long-term R-value. Used in conjunction with the appropriate joint closure system, THERMAX™ Sheathing with its low perm rating helps to reduce moisture condensation within and behind the insulation.
THERMAX™ Sheathing is specially designed to have a Class A fire rating and can be used in a range of concealed and exposed applications, above and below grade, and can be used in exterior walls. Because of its improved fire performance, THERMAX™ Sheathing is especially appropriate for hourly rated assemblies.
THERMAX™ Sheathing is approved for use, per Section 2603.5 of the International Building Code, in Exterior Walls of Types I,II,III and IV construction. THERMAX™ Sheathing is designed for use as continuous insulation in both interior and exterior applications to assist in meeting and exceeding both the most current IECC and the ASHRAE 90.1 energy standards. Maximum length is 30 ft. (9.1 m) and maximum thickness is 4.25" (108 mm).
Use with Dow Wall and Floor adhesive or Dow Enerfoam to adhere panels to concrete walls and fill voids between panels. Thermax is a closed cell foam product and an outstanding moisture barrier.