The House of 42 Doors is leaky, and I suspect I'll be spending the better part of the next five years trying to find and plug all the cracks and holes that help drive up our heating bill. Great Stuff foam and caulk are two tools that I'm learning to love.
Access to the basement is via the back entry, which is unheated. There is a door at the bottom of the stairs that separates this space from the "heated" basement (which stays at a constant 48 degrees). I suspect that the basement is so cold due to two reasons. First the basement has no insulation in it and second there is a lot of cold air leaking in from the outside. One of the places that this air leaks in is around the door frame at the bottom of the stairs.
Somebody in the past had taken newspaper, wadded it up and stuffed it into the cracks around the door frame to help cut down on drafts. I took this out over the weekend and replaced it with Great Stuff. Based on the dates on the newspapers I found, I'd say that 1956 must have been a very cold winter.