To prevent any attic air leakage, the following are some of the materials (not limited to) that can be used for attic prep:
- Glass or mineral fiber insulation as a backer for other sealants, meeting ASTM 665
- Backer rod (preformed closed-cell foam rope) as a backer for other sealants,
- 6 mil (0.l50 mm) polyethylene sheet (used for ground cover or winter-warm side application only)
- Moisture permeable air-impermeable wrap material, flame spread 25 (cold side cover),
- Foil/scrim/Kraft facing ignition barrier per IRC 2009 R316.5.3
- Netting to hold blown insulation in an open cavity,
- FSK or vinyl faced duct wrap insulation R-8 nominal 3” meeting ASTM C1290, and C1136 (facing)
- Soffit ventilation air chutes for 16 or 24-inch rafter spacing ventilation air chutes must extend over existing insulation,
- Insulated flex duct 4 and 6-inch diameter for exhaust fans (no tape, use 4 zip ties