I have lived in my home for 33 years- never had any problems with the plaster. House is in the UP of Mich and over 100 years old. There was NO insulation ever and this year we had the attic insulated and vented = cellulose. The first floor is fine- the second floor (which has always been unheated but never a problem) suddenly has many plaster cracks. Looks like expansion. Opinions please...did the attic insulation cause this and how? .