Insulate Your Unconditioned Garage

Making sure the spaces between an unconditioned garage and conditioned spaces are insulated properly can save money and energy as well as safeguard indoor air quality as your garage may be a source of multiple pollutants. Make sure to never leave your car engine running with the garage door closed as this can lead to death from carbon monoxide from the car exhaust. 

For this DIY, you will need:

Blanket insulation

wire fasteners

tape measure

utility knife (sharp)

caulk and foam sealant

caulk gun



respirator or dusk mask

googles (eye protection)

protective clothing (long-sleeves, pants, gloves)

Choosing materials that don't need specialized tools or equipment to install will make your job easier. 


  1. Make sure that you purchased insulation with the correct width and R-value.
  2.  Seal all the air gaps in the floor between the garage and the conditioned space as well as the garage and the outdoors. For gaps that are smaller than 1/4 inch, use caulk. For gaps 1/4 inch to 3 inches, you should use foam. 
  3. Fit insulation between joists Ensure insulation extends to the outside edge of each joist bay and is in contact with blocking or rim/band joist and the subfloor above. When using kraft-faced batts, install kraft facing against the conditioned side of the cavity. The kraft facing creates a vapor retarder that prevents trapped moisture from reducing the insulation's effectiveness.

  4. Make sure to adjust the insulation for a snug fit. The ends of the insulation should be butted snugly together and should also be in full contact with the subfloor of the conditioned space above.

Referenced from 

New York Energy Audit