How to Insulate a Garage to Keep Cold Air Out

Things You'll Need

  • Insulation

  • Poly

  • Sheetrock

  • Stapler

  • Drill

  • Sheetrock screws

  • Garage door insulation kit

  • Utility knife

  • Adjustable wrench

  • Glass cleaner

Insulate your garage so that you can use the space during winter.

Living in an area where the weather turns cold offers little choice for uses of the garage unless you insulate the garage to keep the cold air out. A garage is a good option for a workout room, a small office, or a craft area if you can keep it warm in the winter. Insulate the ceiling, walls, and garage door, and the garage will be ready to park the cars or add a useful space.

Types of Insulation

Step 1

Choose the batt form of insulation that is the correct size to fit snugly between the studs or joists, which is made from fiberglass and rock and comes in rolls. According to the Department of Energy, "Insulation is measured in R-values—the higher the R-value, the better your walls and roof will resist the transfer of heat." R-values for batt insulation range from R-13 to R-21, depending on the size used.

Step 2

Select loose-fill insulation to use to spray into areas that are not accessible. This insulation is made from fiberglass, rock wool, and polyurethane foam, which is good so drywall does not have to be torn down to insulate behind it. R-values depend on the thickness and range from R-13 to R-48.

Step 3

Use rigid foam insulation where there are space limitations. The R-values range from R-4 to R-6, which is 2 times greater than other insulation of the same thickness.

Insulate Ceiling

Step 1

Install a ceiling to create a base for the insulation to be laid on. Use 5/8 inch, fire coded, sheetrock and plastic poly. With a staple gun, attach the poly to the joists of the garage ceiling. Begin at one corner and work your way across the entire ceiling. Keep the poly tight, and staple every foot.

Step 2

Install the sheetrock by positioning the first 4 x 8 foot piece in a corner of the ceiling. Use your drill to insert a screw in each corner, into the joist and in the middle to hold the sheet up and in place. Put a screw every 6 inches throughout the sheetrock along the truss line.

Step 3

Place the next piece of sheetrock tightly against the first sheet, and install the same way. Continue this process, cutting pieces when needed to fit, until the ceiling is covered. If there is not an attic access to the garage, leave a section in the corner of the garage open to allow access to get up above the sheetrock ceiling.

Step 4

Roll out batts of insulation, 1/2 inch smaller than the size of the trusses, inside the trusses above the sheetrock until the entire ceiling is insulated.

Insulate Walls

Step 1

Use faced batts of insulation, and insert between the wall studs. Staple the facing, or the treated paper backing, to the outside edges of the studs to hold the insulation in place.

Step 2

Cover the insulation with plastic poly by starting in one corner and stapling along the studs every foot, keeping the poly tight. Continue installing the poly until all of the wall insulation is covered.

Step 3

Install fire-coded sheetrock on the wall against the house if it is an attached garage. Choices for the other walls include paneling or particle board. Install by placing a 4 x 8 foot sheet over the poly and securing with screws, using a drill, along the studs. Place the next piece tightly alongside the first piece and secure. Continue until the walls are covered.

Insulate Garage Door

Step 1

Use a reflective foil insulation kit, which installs a utility knife, adjustable wrench to remove and re-install the hardware on the door and cleaning supplies such as glass cleaner. Follow the kit directions or see step-by-step directions provided by Texas Garages.

Step 2

Choose from two types of foil garage door insulation kits, including single foil or two layers of bubble film between aluminum. Either type will insulate the garage door, and you will feel the results immediately.

Step 3

Install panel garage door insulation by placing the pre-cut panels inside the garage door channels. Choose from fiberglass or an insulated plastic that is laminated. Both are easy to install and create a finished look

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