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Garage Insulation: Step-by-Step How-To Guide

Comprehensive instructions for Spray Foam, Foam Board, and Batts & Rolls installations for garage comfort and energy efficiency.

Before You Start

  • Wear PPE: gloves, long sleeves, eye protection, and a respirator or dust mask.
  • Check for moisture issues, leaks, or mold before insulating.
  • Ensure proper ventilation and drainage are in place.
  • Seal all air leaks around doors, windows, and penetrations.
  • Consider insulating garage door separately or replacing with insulated model.
  • Check for electrical wiring and plumbing before drilling.
  • Consider hiring professionals for spray foam installation.

Spray Foam Insulation

Best for garage walls and ceiling. Provides excellent air sealing and moisture resistance. Professional installation recommended.

  1. Hire a licensed spray foam contractor for proper installation.
  2. Choose closed-cell spray foam for moisture resistance (R-6 per inch).
  3. Ensure proper ventilation during application - foam releases gases.
  4. Contractor will apply foam to garage walls and ceiling.
  5. Foam expands to fill gaps and seal air leaks completely.
  6. Allow foam to cure completely before covering.
  7. Trim excess foam flush with surfaces using a saw.
  8. Install drywall over cured foam for fire protection.

Foam Board Installation

Excellent for garage walls and ceiling. Provides good R-value and moisture resistance. Use extruded polystyrene (XPS) or polyisocyanurate.

  1. Clean garage walls and ceiling, remove any debris or loose material.
  2. Choose foam board thickness: 2" (R-10) or 3" (R-15) for adequate insulation.
  3. Cut foam boards to fit between studs using a utility knife.
  4. Apply construction adhesive to the back of foam boards.
  5. Press foam boards firmly against garage walls and ceiling.
  6. Seal all joints between foam boards with foil tape or caulk.
  7. Install foam boards from the floor up to the ceiling.
  8. Seal gaps around pipes, wires, and other penetrations.

Batts & Rolls Installation

Most economical option for garage walls and ceiling. Install between studs with proper vapor barrier placement.

  1. Measure stud spacing (typically 16" or 24" on center).
  2. Use faced fiberglass batts with vapor retarder toward living space.
  3. Cut batts to fit snugly between garage wall studs.
  4. Install batts with paper facing toward the interior (warm side).
  5. Staple flanges to stud faces every 6 inches.
  6. Fill gaps around pipes and wires with small pieces of insulation.
  7. Install vapor barrier over insulation if using unfaced batts.
  8. Cover with drywall for fire protection and finish.

Pro Tips

  • Consider insulating the garage door separately for better efficiency.
  • Install weatherstripping around garage doors and windows.
  • Ensure proper ventilation to prevent moisture buildup.
  • Check local building codes for fire protection requirements.

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