How to Insulate a Garage Ceiling

Lead Image
  • 4-15 hours
  • Intermediate
  • 200-2,000
What You'll Need
Tape measure
Piece of paper
A pen or pencil
Insulation pads (Enough to cover ceiling)
A high powered staple gun
Copper or sheathing (Enough to cover ceiling)
An electric saw
A ladder
Safety goggles and gloves

Insulating the garage ceiling is a quick and simple way to warm up one of the coldest parts of your home. This will make the garage space more appealing to work in and allow you to store a greater variety of items that may currently be cluttering up your house. Garage ceiling insulation is cheap, accessible, and easy to install. It will save a great deal of energy as you won't have to power up your mobile heaters.

Step 1 - Measure the Ceiling

Measure the length and width of the garage ceiling. Use the ladder and tape measure to take detailed readings of all sides of the roof. Calculate the same measurements from the floor. These measurements should be the same as on the ceiling. Write down the measurements and multiply them together. This will give you the square foot of the ceiling area.

Step 2 - Measure Joists

insulation filled joists and walls

Measure the distance between each wooden joist because this will determine the amount of insulation you purchase. Also measure how deep the joists drop. This will commonly be eight or ten inches in the majority of garages. Write down the measurements. The further down the joists extend, the bigger the insulation pads will need to be. Some companies will cut you tailored insulation pads if you give them specific measurements. This will cost a little extra but will stop you having to modify them as you go.

Step 3 - Assemble Pads

Use the ladder to get up close to the ceiling. There are different garage ceiling insulating materials you can use but fiberglass is the most widely available. It is strong, cheap, and adjustable. Start putting the pads into place and use a high strength staple gun to secure them into position. Overlap and adjust the size of each pad as you go. Use any leftover pieces or scraps to fill in all gaps on the ceiling. You should end up with a roughly flat ceiling surface which is level with the bottom of each joist beam. Use goggles and safety gloves if you need to adjust the size of an insulation pad using the electric saw.

Step 4 - Attach Copper/Sheathing Layer

insulated garage

Finish by attaching a sheet of copper or sheathing all the way over the surface of the insulation pads. These materials are commonly used to line roofs and to stop warmth from escaping. This is not totally necessary but is a good idea for even more added insulation. You can cut sheets similar to the size of the pads. Fix these by stapling the layers into place around the perimeter of your new ceiling.

Step 5 - Seal Garage

Once you have finished the job, lock the garage. Leave it for two or three days and it should feel noticeably warmer the next time you go in. Sealing the garage will give the insulation time to start working.