Use a combination of these different air sealing materials.

• Caulk: Seals gaps of less than ½". Select grade (interior, exterior, high temperature) based on application.
• Spray foam: Fills large cracks and small holes. It can be messy; consider new latex-based foams. DO NOT USE near flammable applications (e.g., flue vents). DO NOT USE expanding types on windows and doors.
• Backer rod: Closed-cell foam or rope caulk. Press into crack or gap with screwdriver or putty knife. Often used with caulk around window and door rough openings.
• Gaskets: Apply under the bottom plate before an exterior wall is raised or use to seal drywall to framing instead of caulk or adhesive.
• Housewrap: Installed over exterior sheathing. Must be sealed with housewrap tape or caulk to form an airtight seal. Resists water but is not a vapor barrier.
• Sheet goods (plywood, drywall, rigid foam insulation): These materials form the air barrier. Air leaks only at unsealed seams or penetrations.
• Sheet metal: Used with high-temperature caulk for sealing high-temperature components, such as flues and chimneys, to framing.
• Polyethylene plastic: This inexpensive material for air sealing also stops vapor diffusion. All edges and penetrations must be completely sealed for an effective air barrier. Poly is fragile, and proper placement is climate specific.
• Weatherstripping: Used to seal moveable components, such as doors, windows, and attic accesses.
• Mastic: Seals air handlers and all duct connections and joints.
• UL181 or foil-faced tape: Temporarily seals the air handler.