I moved into a house 5 months ago that is from 1960.It was being renovated and new drywall was installed. After the first month hairline cracks appeared in the ceiling running from one end of the room to the next. The cracks are getting more pronounced as time goues by. The cracks seem to be on the seams of the drywall pieces. cracks are also above doors and also corners have drywall cracking off revealing underneath metal. It seems the drywall was not done correctly?