How Much Insulation Should I Put in the Ceiling of My Garage?

Regions

• With garages that double as workshops or hobby rooms, it's a good idea to add insulation to the walls and the ceiling of the garage. During cold winter months and hot summer days, an insulated garage will provide added comfort if you must work inside it. The area of the country you live in determines the amount of insulation that goes into the ceiling and walls of a garage. Garages attached to homes in Southern California or Florida take far less insulation than a home in the Great Lakes region of the United States.

Open Rafters

• Garages with open rafters will require rigid board insulation or batts installed between the rafters. To fit batt insulation between the rafters, measure the distance between one rafter and the next and purchase insulation for this width. Purchase insulation in batts or rolls and cut it to fit, depending on your specific needs.

How Much Insulation?

• Depending on the region, ceilings take double or more the insulation used in the walls. In homes with R-19 insulation in the walls, install R-38 or greater in the ceiling or between the rafters of a garage. If the garage was built with standard 2-by-4 construction, webbing may be needed to hold the insulation in place as the height of double batts usually extends beyond the height of the rafters and won't stay in place without extra support. The "R" in the classification refers to its resistance to heat flow.

Insulate the Garage Door

• To add extra insulation to the garage, don't forget the garage door, a prime source of escaping energy. Fiberglass insulation sandwiched between foil helps to insulate garage doors and keep needed energy in. This insulation is usually about an inch or more thick and applied with an adhesive.