Should You Insulate Your Garage Ceiling?

If you’re planning on heating or cooling your garage, you need to have as much insulation as you can. We’ve talked before about the need to insulate your garage door and walls, but what about the ceiling?

Usually, I recommend having insulation on any exterior wall, but there are a couple of times when it’s absolutely critical.

If you have living space above your garage, or a roof that traps the heat, then insulating your garage ceiling is a no-brainer.

But is insulating your garage ceiling right for you?

Let’s look at some of the benefits and briefly overview the installation process.


The Benefits of Insulating Your Garage Ceiling

Insulating your garage ceiling has several benefits, and you don’t have to spend a lot of money to get them.

Here are what I think are some of the most important ones:

  1. Insulation is the only way to keep the heat out: Your garage is the largest non-insulated space in your house. I’ve talked a lot about insulating your garage door. Still, it’s essential to keep your garage ceiling dialed in and efficient too.
  2. Heat rises: If you have living space above your garage like I do, that heat will go straight through your garage ceiling into the floor above. That can easily increase the overall temperature by several degrees in the summer. That adds to your air conditioning bill, especially if you’re using a portable air conditioner.
  3. Insulation is an excellent sound barrier: Whether you use your garage for making music, storage, parking cars, or working out, a little less noise sound-deadening insulation will be perfect for everyone else in the house.
  4. Insulation often raises the value of a home: Having a well-insulated home can often mean the difference between a potential buyer choosing your home or your neighbor’s. It might be simple, quick, and cheap, but it’s nice to move into a home that already has insulation.
  5. Increases the life of the roof and the floor above it: Drastic temperature changes can expand and shrink the wood and drywall in your home.

To me, that’s more than enough reasons to insulate the roof of your garage.

Better yet, many homeowners who’ve completed the project point to this as one of the cheapest home modifications that you can make.


How to Insulate a Garage Ceiling

If you’re the DIY type, I want to give a little overview of how you’d go about adding insulation to your garage ceiling.

This isn’t meant to be a ‘how-to’ guide. Instead, think of it as a way to determine if you should DIY it or hire a professional.

First, let’s take a look at some of the stuff you’ll need.

Tools and Materials

Before you get started, you’ll need to gather a handful of supplies. Insulating your ceiling can be finished in a day, but I still recommend having a helping hand or two.

Supplies:

  • Insulation (obviously): This can be spray foam, insulation batts, cellulose, injection foam, or whatever other of insulation you prefer. There are pros and cons to each, so make sure to research before you picking the cheapest option. Humidity, temperature, and packing all change the effectiveness of each material.
  • Standard tools: This will vary depending on whether you have a ceiling in your garage and what type of ceiling it is. Expect to need cordless screwdrivers, cordless drills, and a hammer.
  • An A-frame ladder or scaffolding: Scaffolding is always a safer choice, but it can be a bit pricey for such a quick and easy job. Another option is to rent some scaffolding from your local big-box store.
  • Safety goggles, gloves, and long-sleeve clothing: Itchiness and irritation are common side effects, regardless of which material you choose. I also recommend grabbing a safety mask to prevent fiberglass from entering your lungs.
  • Vapor barrier: A vapor barrier is a plastic or foil sheet that helps block moisture from collecting where you don’t want it. Without it, mold and bacteria can form throughout the garage, including inside the insulation. Once mold starts to grow, you’ll have to rip out everything and start over again.

How to Insulate a Garage Ceiling

Once you’ve got all the materials you need, it’s time to get started.

  1. Remove everything from inside your garage: Insulation is messy, and you don’t want to get any of it on your valuables. Fiberglass has a tendency to get caught in weird spaces!
  2. Locate all electrical boxes: Make sure that they have room to heat up without causing a fire hazard. There should be plenty of space around all wiring and other electrical parts.
  3. Install the vapor barrier by stapling it into place: Remember, a vapor barrier is just as important as the insulation. If there’s any condensation or mold on the surface, remove it before installing the vapor barrier.
  4. Place insulation snugly against walls and rafters: Batt insulation can be moved around if it doesn’t overlap another piece. If you overdo spray foam, you can cause gaps in the insulation. Most importantly, never allow gaps or spaces between any insulation.
  5. Replace your ceiling panels

That’s all there is to it!

Adding insulation is one of the most straightforward projects that you can do around your house. I’ve added insulation to my garage walls, and you can see all of the details (and a lot of pictures) here.


Common Mistakes

As with any project, there are some common mistakes to watch out for:

  • Mind the gap: Insulation needs a small amount of air to work properly. If you tightly pack fiberglass insulation together, it’ll lose it’s effectiveness. Batt insulation needs small air gaps between the fiberglass to help block outside temperatures.
  • Stay safe! Use proper safety equipment. Seriously. Fiberglass is itchy, so wear long sleeves and gloves. Safety glasses keep small particles out of your eyes too.
  • Using too little insulation: Insulating one job where you really can’t cut corners. Overlapping, gaps and excessively thin insulation will all cause problems down the road.
  • Insulating over an electrical box: This should go without saying, but covering up an electrical box is a fire hazard. Don’t do it!
  • Use flame retardants if code requires it: Some garages require flame retardants to be installed in addition to the insulation. Make sure you check local fire codes before you start working.
  • Don’t skip the vapor barrier! Nothing is worse than needing to re-do a project because there were problems down the line. Vapor barriers help control moisture and let your insulation do its job: control temperature & deaden sound.

These may seem like simple mistakes, but they’re all too common.

The good news is that if you’re not confident in your ability to DIY the project, you can hire someone else to do it for you. Not only that but they’ll be held responsible for any damages rather than yourself.

John Manville R-21 Unfaced Fiberglass Insulation Batt 15 in. x 93 in. (10-Bags)
Buy at Home Depot
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