It's annoying, no, it's really annoying when you spend all kinds of time in the summer repairing, then smoothing out your walls and ceiling, painting them with primer, insulating the attic and then, only then, when the weather gets cold, they crack up like hell! It looks like a plate tectonics map on my wall! Don't even mention the ceiling. The cracks are all hairline cracks. That is the only good thing. That and the fact that we haven't painted the walls with anything other than white primer. These cracks could have always been in the original wall and are now appearing because the weather got cold. On the other hand, since the attic is now insulated they may be forming because the air flow pattern of the room has changed for the first time in 163 years and the house is pissed off. Anyway, I already fixed them and it seems to be working. (I had to do something between coats of paint on a closet door.)Years ago I saw something on "Good Morning America" or something like it about fixing cracks in walls. One solution was to fill the cracks with latex caulk. I have done that before but these cracks are way too fine to fill with caulk. So I did the next thing that I remembered. I found the bucket of white exterior latex paint that I had stashed away in basement and, using a 1" brush, painted over all the cracks with three coats of paint. I made sure to fill the cracks with paint if it was possible. The theory behind this is that as the walls expand and contract the latex paint will stretch over the cracks and they shouldn't reappear through the paint. Of course when I came back to put the second or third coats on I would always find a few more cracks and I bet if I looked again today there would be even more. I would post a picture but with all that white it would be like trying to spot a white cat in a snow storm. Oh well. The way I see it the house is just living up to its name!