plaster wall cracks? help!
i have lived in a 1925 home from seven years. the walls have always had a few lines in them, but no real cracks. my wife painted right after we moved in and it seemed to hide them all. this summer i had several layers of ceder shakes taken off and ashpalt shingles installed. at the same time i had a couple of roof vents installed and a bathroom fan installed. we were in the house when they were taking the shingles up on the roof and throwing them around. we felt the house bang and shake. we noticed a couple of new cracks right away.
this was six months ago. it is now January and we well into our second full month of record cold winter (10 to 20 below on a regular basis). we have started to notice a lot of cracks in the last six weeks. i feel like i am seeing cracks grow on a daily basis noe. they almost aren't craks though. a few of them are cracks, but most of them are little ridges that are raised to the touch.
what does everyone think is happening? what should i do?