If you plan to heat your garage, insulation is a good idea. You can choose the same insulation materials as the rest of your house. However, some types are better than others depending on how the garage is constructed. Insulating your garage door is another option. It has different requirements than walls and ceilings.
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Garage Insulation Basics
If you are adding a garage heater to your home, it is worth insulate the garage. Insulating is not necessary if you aren’t adding heat. Insulation is often thought to add warmth. Insulation does not slow down heat transfer through the insulation barrier (wall, ceiling or floor). This is true for both hot and cold climates.
Insulating an attached garage, which is not heated, may provide an additional thermal buffer between your home’s exterior and the outside. This is not required by any state as part of its energy efficiency mandate. This is also unlikely to offset the cost of installing extensive insulation. However, walls shared with the house should be insulated to their full potential.
Sealing Air
Air sealing is also crucial in combination with insulation. Garages are often not designed to be airtight, and they have many air gaps that open to the outside. Although you can insulate garage walls, ceilings, and doors to the highest R value (the higher the number, the more effective the material is at insulating), you will still waste heat if you don’t fill the remaining air gaps.
Before insulation, seal any cracks or gaps in your garage with low-expanding spray foam. This can be messy if you wait until insulation has been installed. Weatherstripping should be installed along the bottom of garage doors, windows, and door frames to prevent drafts.
These are five types insulation that you can use in your garage.
Fiberglass Insulation
Fiberglass insulation is the most common type in garages, just as it is in homes. Fiberglass is available in long blankets or precut batts that can be fitted between ceiling joists and wall studs. Also available is loose-fill fiberglass that can be blown into garage attics above a finished ceiling.
It’s a good idea for ceilings and walls to be exposed (not covered with plywood or drywall), to use paper-faced fiberglass bats or encapsulated fiberglass balls that have been wrapped in plastic film. These will give your walls a more polished look and prevent the insulation’s itchy fibers from getting in the way.
- It is easy to use
- It is easy to frame
- It’s affordable
It is easy to use
It is easy to frame
- Fiberglass irritates skin, eyes, lungs
- Sensitive to moisture
- Incorrectly installed, fire hazard risks
Fiberglass irritates skin, eyes, lungs
Sensitive to moisture
Incorrectly installed, fire hazard risks
Cellulose Insulation
Cellulose, a loose-fill insulation, is on the rise. Cellulose is made mainly from recycled newspapers and treated using a fire retardant. It’s usually blown into ceiling and wall cavities with a special blowing device that also aerates and fluffs up the cellulose. You can rent a blower at most tool rental shops, or ask your local home center to loan one for you if you purchase your cellulose.
Cellulose is not suitable for garage ceilings or walls because it is loose-fill. If your garage is not finished but uninsulated, you can add cellulose to it by drilling strategic holes in the wall material and spraying insulation into the spaces between the framing members.
- Environment friendly
- Fire-resistant
- Insect-resistant
- Inflexible
- There is a risk of settlement over time
- Requires drywall
- Costly
There is a risk of settlement over time
Insulation with rigid foam
Rigid foam is available in sheets measuring 4×8 feet and thicknesses ranging from 1/2 inch to 4 inches. Expanded polystyrene is similar to Styrofoam, extruded and polyisocyanurate are the most popular materials. Rigid foam has a high R value per inch and can be cut to fit any space. Rigid foam is a great choice for garage doors and thin walls.
- High R-value
- Good noise reduction
- Option affordable
Good noise reduction
- Cut-to-fit installation
- Tunneling can be a problem for pests and insects.
- There is a risk of being too tight/not adhering to air-venting codes
Tunneling can be a problem for pests and insects.
There is a risk of being too tight/not adhering to air-venting codes
You can use rigid foam with plywood or another subfloor material to insulate your garage.
Warn!
You should check the fire rating of rigid foam. Some types are not fire-resistant, and therefore are not suitable to be used in exposed areas.
Spray foam insulation
Spray foam, beyond the low-expanding canned products, is great for air sealing and R-value. Spray foam is a high-end product that’s often used to construct energy-efficient garages. It might be a good choice if the garage is being converted into a living space.
- Seals tightly
- Ideal for tight spaces
- Resistant to mold and insects
- High R-value
Seals tightly
Ideal for tight spaces
Resistant to mold and insects
- Costly
- Professionals install the best
- Can you expand too fast or too slow?
- As it ages, there is a risk of shrinkage
Professionals install the best
Can you expand too fast or too slow?
As it ages, there is a risk of shrinking
Garage Door Insulation
Insulating your big garage door and garage ceiling is a must. For standard garage doors made of metal, you can either buy insulation kits or cut Reflectix sheets or rigid foam insulation to fit each section. Garage doors’ structural metal ribs are a great conductor of heat and don’t usually get insulated. The door’s overall thermal performance will fall well below that of the insulation.
Garage doors require special attention when sealing with air. Use a special garage door trim that has an integrated weather-seal strip to seal the sides and top of your door. Use a “bottom seal”, a rubber gasket to seal the door’s bottom. You can choose from a variety of sizes to fill in small or large gaps between your garage floor and your door.
- Temperature inside can be affected by approximately 20 degrees
- Door stability and durability are increased
- Reduces/dampens noise
Temperature inside can be affected by approximately 20 degrees
Door stability and durability are increased
Reduces/dampens noise
- It may not be necessary
- Door springs can be prematurely worn by extra weight
- If panels are not properly installed, they could become misaligned.
It may not be necessary, door springs can be prematurely worn by extra weight. If panels are not properly installed, they could become misaligned.
