How I Winterized My Cheap Garage Door

Valerie Burge
by Valerie Burge
5 Materials
2 Hours

My garage door is very cheaply made, it’s basically hardboard (which is the thin material at the back of bookcases). The garage also isn’t heated. I use it as a workshop, but during the winter it’s pretty much useless, due to the cold temperatures. The temp inside the garage is the exact same as outside. I’m about to work on a pretty big painting project, which requires a minimum of 12° C (53.6 F) for the paint to properly dry and cure, so I decided it was finally time to invest in a new insulated door! I got the quotes, all set to order…but…they were looking at an install date of March 2022! Whomp whomp.

Since I’m stuck with the crappy door for another cold Canadian winter, I decided to winterize it. But I will forewarn you, this post is about functionality and comfort, NOT beautification!


Bottom Seal

To rewind a little, last year snow was coming in underneath the door and forming snow drifts inside the garage. I bought the rubber strip to replace it, but when I tried to remove the old one, I realized the door was not put together properly. I won’t bore you with the details but the bottom line is that was not going to work. So instead, I cut away the old rubber track and applied three layers of foam tape, the wide, thick stuff that is meant to line your truck when you put a camper on there. It’s called ‘Camper & Truck Panel Foam Air Sealing Tape.’ Surprisingly, it worked really well! A few times last winter the door froze to the cement as it was lifting and I though “Uh oh, that seal is coming off for sure.” But it didn’t!!! Impressive. 

But over the past year the foam had compressed and there was another small gap, so I added one more layer of foam. Now the bottom is sealed tight again.

Foam Air Sealing Tape

The Door

I measured the panels inside the door, as well as the depth (the distance the metal ledges stuck out around each panel). I decided to go with polystyrene insulation sheets. I found two types at Home Depot at 1” depth, but I went with the one with a higher R-value (the higher the R-value the better the insulation). 


I needed two panels to fill my door and because the full sheets would not fit in my car, a really nice young man at HD helped me cut them into pieces. We cut them at 20” (the height of my garage door panels), three strips from each. 

Cut into car-sized strips

Because we had already cut to the correct height at HD, all I needed to do was trim each panel to the correct width. They are super easy to cut using a utility knife and a straight edge.

Trimming the width

Once I sliced through I snapped the piece back and used the utility knife to cut the plastic backer on the opposite side.

So easy to cut

I glued the panels to the door, using construction adhesive for foam boards. 

Foam board adhesive

The cut pieces fit nice and tight into the spaces. I pressed on them to make sure they got a good adhesion to the doors. But not too hard, I had visions of me flying through the door like the Kool-Aid man if I pressed too hard.


Next was the two top panels, which had windows. I measured out the panels and windows and cut my foam according to those measurements. 

Cutting out for windows

Once I had the first one done, I used it as a template to draw out my cuts for the second panel. 

Template transferred

Sides of Door

I wanted to seal the sides of the door as well. I had tried using weather stripping, but it didn’t work and actually jammed the door. Since I knew I couldn’t use anything that would obstruct the door, I drew a pencil line where the edge of the door came in contact with the door frame.

Marking the edges of the door

Then I attached strips of the leftover polystyrene underneath the door track, just a little outside the pencil line. It’s not a perfect seal, but it helps! I didn’t want to use glue on the door frame, because that won’t be replaced when I get a new door, so I used brad nails to attach it.

Sides of door
Door fully insulated

I had two pieces of insulation left over and wondered if they would fit above the door, to cover in the fiberglass insulation, and they were the perfect width!! I didn’t even have to trim them. They’re about an inch too short to fit perfectly to the top, but still much better than it was before.

And done!


I turned on the heater to see if I could get the temperature up to 12° C (for painting)…and it went up to 15° after a few hours!! At that point I switched off the heater. Roughly 12 hours later, my garage is still 9° warmer than the outside! In previous years, when I used a heater, the garage dropped down to the same temp as outside within an hour of shutting off the heater. 

I’m very happy that I’ll be able to use my workshop over the winter months. It was a quick and easy project and well worth the effort. My only regret is that I didn’t do it years ago! It’s not pretty, but it’s functional! It was never pretty to begin with, so there's no loss there.

Suggested materials:
  • Polystyrene panels x 2   (Home Depot)
  • LePage PL 300 Foam Board Adhesive   (Home Depot)
  • Camper & Truck Panel Foam Air Sealing Tape   (Home Depot)
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Frequently asked questions
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3 of 4 questions
  • Patti Patti on Dec 02, 2021

    Awesome….I’ve been thinking about doing this for some time! My only question is: why didn’t you go for the high density foam board insulation panels? (Usually blue). They have much higher r-values.

    Just curious! 😊Patti

  • Mary Mary on Dec 02, 2021

    I wonder if this would extend our ability to use our garage in Arizona. It’s too hot for about 5 months a year. Any thoughts?

  • Kathy Dorn Kathy Dorn 2 days ago

    Will this in any way help keep mice and bugs out? Or would it be even more inviting looking for warmth?

Join the conversation
4 of 38 comments
  • Sandy Sandy 2 days ago

    What a great idea! I never thought about insulating my garage doors with insulation panels, but it makes sense. My two garage doors leak like sieves and you can see daylight flood underneath the doors. This is a simple solution and would give me back my workspace. Thanks for the excellent instructions! 👍😁

    • Valerie Burge Valerie Burge 2 days ago

      I'm glad I was able to help!! They really are super easy fixes that have a big impact. Best of luck winterizing yours! 🥰

  • Carol Harris Carol Harris 2 days ago

    I think it looks great and anyway no one sees it but you, well done.