We live in Northern Illinois. Five or six years ago we had the roof replaced on our detached, single family house. The job seemed to be well done and we had no complaints. This afternoon, however, as I lay down on my bed for a moment, and, looking straight up, noticed a nail protruding through the white, finished ceiling directly above me. I look at that spot in the ceiling multiple times a day, and there is no way that the nail was protruding before this afternoon. The house has two stories, and a 16 foot ceiling in that room. No one, to my knowledge has been on that part of the roof since the new roof was put on. So, is it normal for a nail to come through so long after the new roof was put on? In any case, what dangers/issues are there with this situation, and what steps might I take to correct the problem? Picture attached.
Looks to me like a drywall screw or nail has "bubbled out". It happens sometimes due to wall movement, especially with weather swings (like a real wet winter or a long drought). It also happens when moisture gets to a nail or screw and causes it to corrode. Hopefully your kinda new roof is not leaking. I don't see any signs of plaster discoloration indicating a leak.
Get a ladder and bang the nail back in (or give the screw a turn) and spackle over it.