How to Insulate Your Garage Door

by Michael Franco
Garage door metal panel hinge

Garage Door Insulation at a Glance

  • Step 1: Mark where retainer pins will go
  • Step 2: Affix retainer pins
  • Step 3: Measure and cut insulation panels
  • Step 4: Hang insulation panels
  • Step 5: Apply weatherstripping
  • Step 6: Test for balance

Your garage door could be costing you money or not offering your home enough protection from the weather if it’s not properly insulated. If you’re now suddenly reaching for the phone to call your local handyman to come and insulate it for you, stop right there. You can insulate a garage door yourself in just a few short hours with the right materials and know-how.

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Read on to learn what you need to do.

Decide If It's Worth It

The first step in this process is to give it some thought. Garage doors are, by their nature, meant to be large openings and, therefore, not very heat efficient. If your door opens many times a day, you'll be letting the heat out anyway and you may not want to bother. In such a scenario, you might want to replace your garage door with one that already comes insulated; steel doors are generally better insulated than wood variants.

You'll also need to consider the location of your garage. If it's detached and unheated, is there really any reason to insulate the door? On the other hand, if it's attached to your home and usually closed, then it might be a good idea to shore up the door's insulation. And if it has its own heat source or, say, a living space above it, you'll not only want to insulate the door, but the rest of the garage, as well.

Importance Of ‘R’

If you do go ahead with a garage-door insulation project, your next decision will be choosing the appropriate R-value for your insulation. The "R" in this term refers to its resistance to heat flow and a higher number means it’s stronger insulation.

Again, the location as well as the use of your garage will come into play here. Not all of us use our garages to park our cars, as counterintuitive as that might seem. Sometimes, the garage can be an extra living area or workshop, meaning the last thing we want is for it to get too hot or cold. If that happens, it means we need to rely even more on heating and cooling systems to create a comfortable climate, which can inflate the energy bill.

If you have a detached, unheated garage, your insulation's R-value can be down around the zero to 6 range, which will save you money. If there's an attached garage without its own heat source, you should be fine with an R-value of 7 to 9, while a heated garage connected to your home would be better served with insulation in the 10 to 13 range. Finally, a heated garage with living space attached should use insulation with an R-value that's at least 14.

A side benefit of insulating your garage door is that insulation can also reduce noise penetration by up to 20% because it absorbs sounds and vibrations as well thermal energy. That means less noise comes from the outside if you’re using the garage as a chill spot. And if it’s your workshop (and weekend band-practice space), your power tools (and power chords) will make less noise outside — enabling you to preserve polite relations with your neighbors.

What Materials to Get

When getting down to work, you'll likely want to buy a garage-door insulating kit. These largely come with two forms of insulation: vinyl-faced fiberglass batting or expanded polystyrene (EPS) foam board.

Each garage door insulation kit comes with its own benefits. For example, the batting insulation made from fiberglass is fire-rated, meaning it was tested for fire resistance and it passed. And polystyrene rigid foam panels offer great heat resistance without being too thick — always an important consideration when planning this project because, if you intend your door to remain usable, you’ll want to make sure that your insulation doesn't interfere with its joints and hinges.

You can complete the project with just the above-mentioned kits, but no garage door insulation job is complete without doorstop vinyl weatherstripping. This will be used to seal the gaps at the top and sides of the garage doors to keep the elements out. Not only will this help maintain the internal temperature, but it’ll also protect the inside of your home from damage that can occur due to rainwater or melted snow seeping in.

Step-by-Step Garage Door Insulation Guide

Now that you’ve determined the level of insulation your situation calls for and procured the necessary implements, it’s time to get started.

1. Make Your Mark

To get the insulation installed, start by grabbing your tape measure and finding the spot that is 12 inches away from the horizontal edge of each garage-door panel and marking it. Then, measure from the vertical rail to the center of the panel and place a mark on that spot, as well. In the end, the mark should look like a plus sign. Do this for every panel, making sure that each panel has two markings.

2. Affix Retainer Pins

Next, take out the retainer pins that came with your kit. These are small spikes with flat bases. Peel the release paper to reveal the adhesive on the base (or use double-stick tape if they don't have adhesive), then firmly place that side on the mark. Repeat this process until you have covered all the marks.

3. Measure and Cut Panels

Before you place the insulation onto the garage door, you’ll need to cut it to fit. If you’re using foam board as your material and want to skip this step, you can purchase pre-cut foam core panels.

Measure each panel’s height and width using the tape measure — and do not assume that each panel will be the exact same size. Add an extra inch to the measurements to ensure a tight fit. Place the batting or foam board panels straight on the floor with the vinyl side down and trim it using a utility knife and straight-edge ruler.

4. Hang the Insulation

With that piece cut, tuck it into the rails of the garage door panel — making sure the insulation is facing the panel. Feel around for the retainer clips and then press the insulation against them until they push through the vinyl facing. Then, insert retainer caps on the pins to secure the insulation firmly against the garage door. Repeat this process until all the garage panels are complete.

And, before you know it, you will have insulated your garage door. See? That wasn’t so hard. But before you pat yourself on the back, don’t forget the weatherstripping.

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5. Apply Weatherstripping

Now that you’re done with the inside, it is time to make sure that the drafts, rainwater and melted snow don’t find their way in from the outside. You'll do this by using doorstop weatherstripping, a mix of a firm material like wood or plastic and a flexible rubber strip.

Check for Fit

Before you hammer in the doorstops, you’re going to want to test fit them first to ensure a tight seal. Place the firm part of the doorstop on the top and side jambs of the garage door. This will make sure that the vinyl weatherstrip is 45 degrees from the doorstop. You’re going to want to temporarily secure the door stops for the test, so just partially hammer a nail into them.

Next, you’ll need to simulate strong winds by applying pressure to the door. If there’s a gap, just move the doorstop to fill it. Repeat these steps on different parts of the door to ensure an even seal. Start from the top and work your way to the bottom.

Install the Bottom Seal

Before you do this, you’ll have to remove the old bottom seal. This can be done by locating the crimped area underneath the garage door, jamming a flathead screwdriver into it and twisting at both ends until it comes apart. This will expose the bottom track’s slot, which you’ll then lubricate with either dishwashing soap or silicone; apply the soap or silicone spray liberally, and don’t skimp. Slide the new vinyl seal into the tracks, and you’re done.

6. Test for Balance

Your garage door should be balanced at all times, otherwise, it can suffer all types of damage over time. Normally, if you open it halfway and let it go, the garage door should remain in place. If you have done the above steps correctly, that should remain the case and you can give yourself a high-five for a job well done: The garage is now a more comfortable and energy-efficient space.

However, if the door falls, it means it’s not balanced and the spring tension needs re-adjustment. At this point, it would be wise to call in the professionals to handle that part.

Speaking of professionals, being prepared with a plan from HomeServe can help ensure that you always have a squad of pros on hand to help with many major home repairs. When an issue arises, you can call the 24/7 repair hotline, and HomeServe will send a local, expert technician to handle repairs, up to the benefitted amount. Learn more about plans from HomeServe today.