How to Insulate a Garage in 4 Simple Steps

Adding insulation to your garage is a relatively simple DIY project that can save you money on energy bills. The benefits don’t start and end with improved energy efficiency, though.

Insulation can prevent heat loss, increase your return on property value, and reduce noise pollution.

If you want to insulate your garage but don’t know where to start, this article has the answers you need in a step-by-step process. We provide a roadmap to enhance your doors, walls, and ceiling. 

So, without further ado, here’s your go-to DIY guide on how to insulate a garage in four simple steps.

What You’ll Need

Your equipment will depend on your insulation type. While we can recommend different options, you need to determine the proper amount of material to insulate your garage.

Here’s a list of all the materials and tools you’ll need for insulating a garage to the same standard as a professional contractor:

• Fiberglass insulation – The most common type of insulation comes in rolls or batts, also known as blanket insulation. A batt is a pre-formed rectangle, while a roll wraps up like a tube of wrapping paper. You can also find loose-fill, reflective, and foam board insulation.

• Garage door insulation kit – You don’t need a garage door insulation kit, but it will make your life easier. The kits take little time to install and can save you a fortune on cooling and heating costs.

• Foam insulation – You’ll need to spray foam insulation to fill gaps and cracks in your garage. Expanding foam fills the crevices to prevent unwanted moisture from getting in and heat and cold air from escaping.

• Drywall – Drywall provides a final layer to keep your insulation in place. Measure your garage’s linear feet and multiply it by the height to determine how much material you need. We recommend buying extra drywall just in case.

• Gloves and long sleeves – Fiberglass insulation can cause rashes and inflammation if it comes in contact with your skin. Wear gloves and long sleeves to avoid irritation.

• A utility knife – A sharp high-quality utility knife will make cutting insulation materials effortless.

• Wood – Wood serves as a guide on top of the insulation, making it simple to shape insulation to the proper size.

• A staple gun with staples – Staples are the leading DIY choice to hold the insulation securely in place.

• A tape measure – A tape measure (ideally 8ft plus) will give you precise cutting lines and panel sizes.

Types of Insulation

When you think of insulation, you probably think of a batt or roll. These foam packs provide sheets of insulation, either cut into rectangular foam panels or wrapped up like a log.

Here are the most popular options for insulation:

• Loose-fill insulation – This type of insulation contains small pieces of foam, fiber, and other materials. These tiny particles conform to the space, whether they’re in your garage door, ceiling or wall. The common types contain fiberglass or cellulose.

• Spray or foam insulation – Foaming insulation has two separate liquids that combine to form foam. When you spray the insulation, the foam expands within seconds, filling the garage cavity. It can inflate 40 to 100 times its original size, making it ideal for filling in hard-to-reach areas.

• Rigid insulation – This type of insulation uses polyisocyanurate, extruded polystyrene, and expanded polystyrene to insulate a garage. The materials offer significant energy savings and improved heat retention. While the foam panels lack the flexibility of loose fill or foaming insulation, they still deliver top-tier performance.

• Radiant barriers – This insulation material uses highly reflective surfaces to retain heat and cool air in the home. It contains several substrate materials, like plastic films, backing paper, and cardboard. Radiant barriers also rank as one of the most durable and easiest to insulate a garage.

How to Insulate a Garage Wall

Step 1: Clear the Garage Walls

If your garage has drywall, you’ll need to remove it before installing insulation or foam board. If you have a multi-car garage, you may need to rent a dumpster so that you can throw away the unwanted material.

Make sure to remove dirt or debris from the wall cavities, too, before continuing with your project.

Keep your eyes peeled for any areas with mold or chemicals. A patch of fungus or a small pool of gasoline can undermine your insulation’s integrity. Gather and deposit these materials at a hazardous waste collection site.

Step 2: Repair Damage to Garage Walls

Grab a can of foaming insulation and shake it vigorously. Attach the straw to the nozzle and spray the insulation in the desired area. Use enough foam to fill 50% of the area since the insulation will expand to occupy the rest of the space.

Give the foaming insulation five to 15 minutes to harden. You can continue adding more foam once the first layer is tack-free. The insulation will take up to eight hours to cure.

Step 3: Install Fiberglass Insulation

Use the staple gun to attach the insulation with the paper side facing the wall stud. The stud should never face you. Leaving the stud exposed will help you apply drywall on top of the insulation.

Place a piece of wood on top of the insulation, using it to trim the insulation to the proper size. Cut excess insulation with your utility knife. Once the panel fits the stud, tuck it into the wall.

Next, simply place staples down the side of the insulation to prevent it from moving during your project.

Step 4: Place Drywall over the Insulation

Drywall protects your garage insulation from moisture, mold, and debris. All you need to do is screw and glue the drywall to the stud.

Don’t let any insulation peek out from behind the walls, and make sure the glue is set before moving on. Excess materials can create a fire hazard for your home.

How to Insulate a Garage Door

Garage doors require slightly more experience when installing insulation. This DIY option utilizes some of the same tools and only takes one or two days to complete.

If you don’t have the proper equipment or expertise, consider hiring a garage door service company.

Step 1: Install the Retainer Pins

Use a tape measure to find a spot one foot from each side of your garage door panel and one halfway between the rails. Mark the locations with a pencil. Center the markings vertically and note the subsections.

Remove the adhesive from the retainer pins. Press the base onto the door panel. Repeat this process for each marking on the panel.

Step 2: Cut the Foam Board Insulation

Cut the foam board to the desired length. Some types of garage insulation come in pre-cut slabs, so you don’t have to adjust them. If you need to cut the materials, roll out the insulation vinyl side down, measure it with a ruler, and cut it with a utility knife.

Remember that no two garages are the same. Measure the insulation individually, making sure that it matches the panel length. Place the insulation on a hard surface, such as concrete or plywood, to ensure a crisp cut.

Step 3: Secure the Insulation in Place

Center the garage door insulation with the panel. Once you have it in the right place, press it against the retaining pin. The insulation will stick to the garage door when the needle pierces the vinyl seal. Repeat this process until all the panels on your garage door have insulation.

Step 4: Apply the Vinyl Weatherstripping

Place the vinyl weatherstripping along the garage door edge. It should form a 45-degree angle. Once it’s in the correct position, flush with the garage floor, and partially nail or staple the weatherstripping into the garage door.

Make sure the weatherstripping can hold up to brisk gusts. Apply pressure to the garage door’s exterior and move the doorstop inward until you create a firm bottom seal. If the gaps between the weatherstripping and garage floor aren’t uniform, readjust the material.

Begin at the top of your garage door. Replicate the effect of strong wind, then pound the nail or staple into place. Continue this process, working your way along the edge of the garage door until you reach the bottom.

Not sure if your weatherstripping is in the right place? Turn off the lights and shine a light under the garage door. You shouldn’t see lighting peaking through the bottom space. You may need to replace your garage door hinges or adjust the spring tension.

Step 5: Add the Bottom Seal Track Slots

You’re in the home stretch. Your insulated garage door has the sides and back in place. Now you need to secure the final space: the bottom seal. Start by removing the bottom seal track slots with a flathead type of screwdriver.

Use your utility knife to remove extra vinyl and fasten the ends with pliers. Remember to crimp each side of the vinyl seal. Securing this area will prevent the materials from cracking.

Step 6: Check Your Garage Door Insulation

After you finish your garage door insulation kit, it’s time to test your work. A properly balanced garage door should remain in place when you lift it halfway. If the door falls, it doesn’t have the optimal balance.

An unbalanced garage door can damage the rest of your garage. It will strain your garage door opener and let cooled air seep out of your home. Homeowners that don’t have the proper tools should consider contacting a garage door service company to calibrate the spring tension.

Tips for Insulate Your Garage Ceiling

You can use the same process to insulate a garage ceiling that you used for your garage wall. Just use thicker insulation. As a rule of thumb, look for materials with R-30 insulation or higher.

Why do you need thicker insulation on your ceiling? Because heat rises. Most of the heat loss in your house involves warm air escaping through cracks and gaps in your roofing or ceiling.

While repairing a garage door or wall deserves your attention, your ceiling should be your top priority.

Cost to Insulate a Garage Door

The cost to insulate a garage door or wall will depend on several factors. How large is your garage? Are the materials low, average, or high quality? Do you need to purchase garage door insulation kits before you start?

It should cost you 50 cents to $1.25 per square foot to insulate a garage door. If you have a two-car garage, expect to pay between $330 and $850. This estimate presumes that you’ll take care of the project from start to finish.

Hiring a professional contractor increases the cost per square foot because you have to pay for parts and labor. Garage insulation basics will set you back at approximately $1.75 per square foot.

If you want a high-quality insulated garage door, prepare to pay more than $3 per square foot.

Choosing the Right R-Value

The right choice of R-value can make all the difference for your next garage door insulation project. But what is R-value? R-value measures the temperature difference between the warmer and cooler surface of a barrier.

The “R,” which stands for resistance, helps consumers understand how well specific insulation works for their DIY projects.

For instance, USAInsulation.net recommends that people in Florida use R-30 to R-49 materials for their attics since the state has a relatively high average temperature.

Meanwhile, states like Maine, North Dakota, and Wisconsin have the highest recommended R-values.

Use insulation with the highest R-value in your ceiling. Higher resistance is more suitable for energy savings in cool climates and can help your house retain its temperature.

You can use insulation with lower R-values for your walls and garage door, especially if you have an older property.

The Bottom Line

An insulated garage door can transform your living space. It can reduce your energy bills and protect your house against Mother Nature while keeping the interior temperature on point.

A little cellulose, drywall, and elbow grease can also enhance your property value.

You don’t need to be a master craftsman to tackle an insulation installation. Insulation kits can save you time and money on your next endeavor, with some home centers even letting homeowners rent kits.

Make sure to check out The Tool Scout blog for more helpful tips and tricks on all your beginner DIY projects.  Best of luck with your home improvement projects, and feel free to reach out to us if you have any further queries.