Garage Insulation R Value
Written by webtechs

What R-Value of Insulation to Use for a Garage?

A lot of people usually don’t think of insulating their garage when they are insulating their house but doing so goes a long way in reducing energy costs for the whole house as it offers an additional buffer.

Insulating the Garage

When you have a room built over a garage, it becomes vital to insulate the ceiling of the garage to avoid the heated area above it from losing its heat. When you insulate your garage, use insulation with the exact same rated R-value as that was installed in your home’s ceiling and walls.

While insulating your garage won’t make it essentially warmer unless you include a heater, it will help to provide additional insulated space for the home. A great deal of people enter and exit the home through their garage, the additional insulation will help make the car start easier in the morning. Use the same insulation to insulate the garage that was used for the exterior walls of the home. If the walls and ceiling are closed in, think of using a loose fill type of insulation, as this type of insulation uses a machine to push the insulation where it needs to go through a hole in the sheetrock. Insulate the garage’s ceiling by using the suggested R-value for your area as advised by the Department of Energy.

Exterior Walls

If your exterior walls were constructed from 2-by-4 inch studs, the maximum insulation that can be installed into the wall while keeping its R-value is R-13 or R-15 as these are each made to fit a recess at a depth of 3 1/2 inches. Because insulation fits the width and depth of the recess between studs, when you condense insulation to fit the space, you take away its insulating properties — the trapped air between the fibers.


When you have a room over your garage, its floor rests on boards supported by joists. If the joists are 10 inches deep, the recess can take high-density R-30 insulation, which is 8 1/2 inches thick, more than adequate enough for floor insulation. If the rafters are open to the garage, (boards that support the roof) use R-38 insulation between the them at the roof, if they are at a depth of 10 inches. To add additional insulation inside the garage, using sheetrock install a ceiling and allow access to the space between the new ceiling and the roof. This allows you to add the required insulation. While some ceilings in the southwestern part of the United States require a minimum of R-19 insulation, most attics or ceiling areas require a minimum of R-38 in the ceiling.

Garage Door Insulation

Use specialized foil-backed blanket insulation to fit the inside of your garage door. A lot of garage-door insulation has an R-value between R-8 and R-12, because it is thin enough to fit the space. This will add insulation to the garage door without hindering its functionality. Another option is purchasing a pre-insulated garage door that might have a higher R-value. If you insulate the garage without insulating the garage door will allow any heat collected in the room to escape through the door.

Best Way to Insulate Garages

When insulating your garage, it’s up to you to determine what type of insulation material works best for your garage.

Your overall goals and expectations and what they are will help you choose the insulation that works best in your situation. If you need a conditioned space that will keep cold air out of your home or extra room, a material that creates an air barrier will benefit you most.

Cellulose and fiberglass insulation don’t provide the kind of air barrier you are looking for in this scenario, so a foam insulation is a better alternative.

Barrier Insulation Offers Garage Insulation Services In Phoenix.

Barrier Insulation Inc. is provider of top-quality insulation in Phoenix, including blow in insulation, spray foam insulation, rolled batt insulation and more. Trust your insulation installation to the professionals at Barrier Insulation Inc. knowing your house will be optimized with the finest quality insulation in the marketplace.

If you are building a new home, or probably just need to remove the old insulation and install new more energy efficient insulation. We proudly offer the valley’s more comprehensive insulation service that helps you save on energy stay comfortable. Give us a call at 602-499-2922.