Question about wierd sheetrock situation

[PDArch]

A friend of mine's ceiling in his garage is having a sheetrock problem. He was sitting inside and heard a noise and went out into the garage to find this....

http://i796.photobucket.com/albums/yy245/jwojnas/SRPart1.jpg

And then a couple of days later it got bigger....

http://i796.photobucket.com/albums/yy245/jwojnas/SRPArt2.jpg

My question is what would cause this? I asked him several questions that I will give you the answers to.

Was anything stored above that area? - No
Any signs of water damage? - No
Any signs of critters in the attic? - No
Any signs of person in the attic? - No . I asked if someone was living up there. You never know.

So other than those things I am kinda at a loss as to what would cause this. It is more curiosity than anything else.

Also the house is around 20 years old and has never had these type of sheetrock problems before. I appreciate any theories about what would cause this. I have never seen anything like this in the time I have been designing houses without an obvious cause.

Thanks for your time.

[Don_P]

Looks like insufficient fasteners, or good connections, for the load. Once it started to pull away it just zippered.

I see a what looks like a crack in the wall in the first pic. Is there damage from a hit recently anywhere... did the ceiling diaphragm react to the building being bumped?

[PDArch]

Looks like insufficient fasteners, or good connections, for the load. Once it started to pull away it just zippered.

I see a what looks like a crack in the wall in the first pic. Is there damage from a hit recently anywhere... did the ceiling diaphragm react to the building being bumped?

I asked him about that crack as I noticed it too. He said it is from settling over the years and not from his wife hitting the wall with the car :). Yeah insufficient fasteners sounds like that would cause this. It is just crazy it took over 20 years for it to fall down. Thanks for the reply.