Using the recomendation above we just had "A Touch of Drywall" repair about 25 feet of defective ceiling seams. Lori, the owner does all the work herself. Prompt, reasonable and very professionally done. Plus she is a pleasant person to deal with. She matched the existing knock down plaster patterns perfectly. If you have a drywall repair, we think she's the one to call.
Phone her at 352-636-6859.
A post above asked why these cracks appear. Lori explained and demonstrated. The orginal installers chinzed during installation and only put in 2/3 the proper number or drywall anchors, so over 10 years the ceiling sheets of drywall begin to sag and shift at the joints from weight and temperature changes. To repair, she strips away all old morter and tape, cleans out the joint, and screws in additional anchors every six inches to stablize the plasterboard. When she screwed in the anchors you could actually see the drywall snug up against the rafters. After stablizing the joint she reapplies the spackling, tape and finishing materials.