rivka

I suspect that it was just a structural weak spot (it appears that the bay windows on floors 2 & 3 were added on, as the laths in the ceiling have a very definite "these start here, and those start there" pattern, where they are attached to different joists), and us using the third-floor bedroom right above that spot added vibration and variable loading to it. That combination put a lot more small flexing on the plaster, and I had the misfortune to be under it at just the wrong moment. It had definitely already started cracking -- I had noticed the crack propagating a while back, but I never could pin down just how much it was moving. I found a fair bit of plaster dust underneath the spot when I came down yesterday morning. I wasn't doing anything that could have triggered it directly, as I was just checking my email. I wasn't happy about the performance of my fantasy baseball squad, but that displeasure isn't what you'd call tangible.

I hadn't realized the plaster could fall; I expected it to be just a cosmetic issue. I know better now, though. :)