Steel Truss

Installation & Design Considerations

• FOAMULAR® insulation installed over the bottom chords of steel truss framing reduces heat loss through the framing.
• Use, large head, screw type drywall fasteners to secure 1” thick, (typical maximum) foam insulation in position.
• Attach drywall over the foam insulation. Use traditional drywall fasteners to secure drywall to the truss bottom chord.
• Foam insulation must be covered on the attic side with an ignition barrier.
• Install full width unfaced Thermal Batts of sufficient thickness to meet energy code requirements.
• Maintain a minimum 1” ventilation passage way at the eaves with vents. Where necessary use Owens Corning Raft-R-Mate® vent baffles to assure proper clearance.
• Attic must not be used as a return air plenum. Provide attic ventilation to meet code requirements.
• Polystyrene insulation must be separated from the building interior with a code approved thermal barrier, typically 1/2” drywall.
• The need for a vapor retarder should be determined by the designer based on local conditions. FOAMULAR® 150 has a perm rating less than 1.1.
• Compliance with local code requirements must be verified.
• Architect must supply detailed drawings to meet project and building code requirements.