Typically plaster ceiling cracks have two causes.
What causes cracks in drywall ceiling.
Small cracks can be repaired by applying plaster.
A wall is constructed with vertical studs that extend from floor to ceiling.
Then sagging may result and the stress from this may create cracks.
When the ceiling joist or trusses are undersized for the drywall ceiling weight that they re carrying.
When the wood rafters expand and contract naturally with changing temperature and humidity it pulls the ceiling joists away from the wall plates.
This article describes the common causes of all types of cracks that appear in drywall or gypsum board or plasterboard walls ceilings in building interiors.
See if the door or window.
This is a sign of structural damage usually related to a weak wall.
The best way to repair a crack in drywall is to re tape the joint.
If they are bigger and sections of plaster are falling you will probably have to remove the plaster and replace it with a drywall section.
Illustrations show where cracks are most likely to appear explain why and suggest both repair approaches to drywall cracks and how to prevent cracking in plasterboard or gypsum board.
Ceiling cracks in plaster ceilings.
If you find cracks in these areas beery recommends another test.
Drywall cracks in ceilings or walls.
Cracks around door frames windows and the ceiling can also indicate your foundation is settling.
House settling and temperature or moisture fluctuations in an attic which result in the expansion or contraction of framing members.
Damaged ceiling joist or trusses.
If you live in a home with plaster ceilings and you begin to see cracks they may be caused by moisture and or movement.
Too much mud too little mud missing drywall tape and drywall secured with internal stresses are some causes removal of pop corn textured or cottage cheese looking ceiling material may leave a drywall taping job that tends to crack at the drywall joint.
Causes of cracks in walls.
Cracks that cause concern are those which run across the length of a ceiling and then continue down a wall along the same line.
These structural members sit on top of the wall plates and are often connected to the plates with nails.
Occasionally a ceiling joist or a truss becomes damaged or cracked this weakens the framing member and the ceiling will bow or sag in.