• In this video, This Old House general contractor Tom Silva shows how to super-insulate an attic.

    1. Apply closed-cell spray foam insulation to the underside of the roof sheathing, filling the spaces between roof rafters.
    2. Once the foam cures, use a reciprocating saw to trim the excess foam flush with the rafters.
    3. Cover the insulated attic roof with ½-inch-thick drywall.
    • 4 to 6 hours
    • About $600 to $800 per 100 square feet
    • Difficulty: Hard
      Spray-foam installation is best left to the pros
Ask TOH users about Insulation

Contribute to This Story Below

      Video Directory

      Selected Topic/Section

      Shopping List

      Expanding-foam sealant

      Closed-cell spray foam insulation