How to Insulate a Garage | 4 Types of Garage Insulation Methods


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The majority of homeowners use their garage for many purposes. You can use it as a warehouse or turn it into a home office or even a home gym. However, since a garage space is usually not as weather-resistant as the rest of your home, it ends up in a sauna on a hot day. Temperatures can reach extreme values, which is unfortunately unpleasant for any activity. It can also reach freezing temperatures in winter, which can damage equipment and water pipes. In this guide, we will discuss how to insulate a garage.

Therefore, if you want to use the space in the garage by converting it into another room, it is worth paying attention to the garage insulation. Insulation reduces heat transmission through your garage’s walls, ceiling, and floor, which is beneficial in any climate, regardless of whether you’re heating or cooling the room.

What to Consider When Insulating a Garage

How To Insulate A Garage

Before starting the insulation process, you need to take care of several things, such as checking the moisture content of the concrete floor and not covering the electrical boxes. If you insulate yourself, it is best to purchase scaffolding for safety and smooth operation.

  • Install the vapor barrier to prevent moisture from accumulating on the insulation foil.
  • Do not cover electrical cabinets installed on the garage ceiling. Also, do not tighten the insulation around the boxes.
  • Concrete is a porous material that quickly transfers moisture. Water can infiltrate through the concrete slab and influence the insulation if it is insulated without a vapor barrier.
  • All suspended objects must be removed to prevent damage to the wall insulation.
  • Cracks, holes, or fissures in the outer wall must be repaired before installing the insulation to prevent moisture damage and mold growth.
  • Polystyrene and plywood added above can significantly increase floor thickness. This leaves an elevated area from the entrance to the garage. You will need edging strips to smooth the edges.
  • When insulating the ceiling, leave a 12-inch gap between the fiberglass insulation and the underside of the wooden roof sheathing. This will help the steam dry out and prevent the growth of mold.
  • Keep insulation three to five inches from light sources. Installation too close to light sources can cause a fire.
  • Be sure to cover the bottom of the garage door and windows with sealing tape.

Tools Needed to Insulate the Garage

Here is a list of the tools you will need to insulate your garage perfectly:

  • Insulation of your choice
  • Ladder or scaffolding
  • Construction tape
  • Utility knife
  • Measuring tape
  • Universal screws
  • Drill driver
  • Hammer
  • A set of screwdrivers.
  • Face mask
  • Eyeglasses
  • Gloves
  • Stapler
  • Vapor barrier
  • Expandable foam to fill cavities
  • Locking pins
  • Sealing gun
  • Plywood or plasterboard
  • Plasterboard screws
  • Sealer
  • Edge strips

How to Insulate a Garage Ceiling

How to Insulate a Garage Ceiling
  • Prepare a ladder or scaffolding. If you are using a ladder, ask a family member or friend for help.
  • Take the measurement. Measure the length and width of the ceiling of your garage. Measure the length and width of your garage ceiling. Then measure the distance between the beams and their depth. They are usually 8-10 inches deep.
  • Cut the insulation material according to the measurements made.
  • Install the insulation in the ceiling and secure it with a clip.
  • If any corner remains, cut the insulation so that it fits exactly. To fill in the spaces, you can also use expanding foam.
  • Complete the process by covering the ceiling with plywood or plasterboard.

How to Insulate a Garage Door

  • Clean the door panels with a cleaning spray.
  • Measure the height and width of each panel, as they may vary in size.
  • Ensure you cut the insulation to the necessary dimensions.
  • Locate 12 inches from the edge of the panel and halfway between the horizontal rails.
  • Take the locking pin, install it, and push it into the panel.
  • Install two locking pins in each panel.
  • Next, place the insulation on the panel and press it onto the locking pin.
  • Take the cap and slide it over the pin.
  • Repeat for all panels.
  • Then, install the seal on the insulation and fasten the nails.
  • Push back the previously installed bottom seal and install a new vinyl seal.
  • Check the function of your door. It should stay in place if you lift it and then release it.
  • If it is loose and dropped, contact the door service to request adjustment.

How to Insulate Garage Walls

How to Insulate Garage Walls
  • Take down the screws and hooks from the walls. For this, you’ll need a hammer and a screwdriver.
  • Clean the insulated space by removing the wall covering.
  • Look for cracks in the walls. Mold might grow if water remains in the holes.
  • Cover its places with sealant.
  • Allow for complete drying of the sealant before installing the insulation.
  • Begin installing fiberglass insulation.
  • Rather than pressing the insulation close to the square, cut it to fit the gaps between the wall studs.
  • Once the insulation is complete, cover it with a vapor barrier and fasten it with clips.

How to Insulate the Garage Floor

  • Begin by putting down a vapor barrier on the floor. Then go with polyethylene, which works well as a moisture barrier.
  • Cover the vapor barrier with a layer of stiff foam. It’s best to use strong pressure-resistant foam boards.
  • Use a sharp knife, cut the pieces on the ground.
  • Cover the insulation layer with plywood sheets. To avoid the plywood seams lining up with the foam seams, make sure it’s perpendicular to the large size of the foam.
  • Separate the panels by 1/4 inch. Allow for seasonal shrinkage and plywood expansion by leaving a 1/2-inch gap around the outer rim.

Frequently Asked Questions

Should you insulate the garage?

If you have the proper insulation in your garage, this will reduce the amount of noise entering your house. In addition, it helps to keep the garage quieter from any noise in the house. While this may seem like a trifle now, you will find that it can be very useful in the future.

What is the best insulation for garage walls?

Rigid foam is a good choice since it has a high R-value, which means it can withstand a lot of heat and provide adequate garage insulation. Rigid foam is best used to insulate garage doors and thin walls in terms of applications.

How do I heat a garage?

Replace damaged seals and seal any air leaks. Add insulation to garage walls and garage doors. Buy a separate heat source, such as electric heaters.

  • Infrared heaters
  • Propane heaters
  • Wall heating
  • Ductless heating systems

How much does garage insulation cost?

The cost of garage insulation depends on the size of the room and the type of insulation you buy. Sebring estimates that garage insulation costs between $ 50 and $ 1.25 per square foot. This means that insulating a garage for two cars will cost about $ 338-845.

Do you need a vapor barrier for your garage?

Yes, this is necessary if you want to insulate and use heat / alternating current. The vapor barrier should only cover an isolated area.

Is it worth isolating a detached garage?

Most free-standing garages will not require an HVAC system. Including thermal insulation and quality windows and doors will be more than enough. However, if you have other features, such as a home gym, office, or living space, then HVAC is probably a necessity.

Is it possible to insulate the garage after its construction?

If the garage is already finished (but not insulated), cut important holes in the wall material, spray insulation into the spaces between the framing elements, and glue the gaps. 


Adding thermal insulation to your garage will protect the space from sudden temperature changes. In addition, the insulation of the garage will allow you to have a comfortable working space all year round.

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