Thanks to Dad’s help [again], we now have a new rear steel entry door into the garage and two new storm doors on the back of the house. Since the previous owner never put storm doors on or painted the rear door frames, the garage entry door was pretty much rotted at the bottom of the frame.
To make matters more fun, they poured the concrete garage floor AFTER they put in the door. Half of the space under the door threshold was empty space and they didn’t waste any effort in insulating under or around the door.
After we installed the new door, we used that expanding foam insulation around and under the door. I swear it’s warmer in that garage already. Should be interesting to see if it makes a difference next winter, especially if I get a new garage door seal on as well.