How I Winterized My Cheap Garage Door

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.

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. 

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.

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

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

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. 

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

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.

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.

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.