What is the cause of a spreading crack in an old ornate plaster ceiling?

Question

The crack starts in one corner of the room and follows the curves of the plaster design in the corner of the ceiling. It is about 12'' long and has got noticeably longer in the last 6 months.

Answer 1

the ceiling is falling in, repair it.

Answer 2

Settling, or moisture change can contribute to this. check DIY.net, HGTV.com or other home improvement sites for info and videos that can walk you through a minor repair. If it's major, you will need a pro.  You should be able to find all the info you need online to make the repair.  

Answer 3

Selleys no more gaps will fix it.

Answer 4

ll cracks are caused by movement in the ground .It could be just the earth drying which cuases shrinkage which in turn will make a house flex also after a long dry spell rain will make it expand. Tree roots growing under the house can also cause this problem.

Sort out the cause if it is the first two it's natural and nothing can be done except for fixing the crack and not just filling with spackfilla will do the job as it will return just as fast, you will have to use gyprock tape over the crack and then paint to remove it properly. ( see your local hardware for the how and material, it's quite easy to do but if you are hopeless in basic repair ring a plasterer to do the job.

Answer 5

movement

Answer 6

It's from the wood in the ceiling flexing due to humidity. You can't prevent it you'll just have to fill it and paint over it.