Interesting experience no matter what the source of the bang was. I want to believe it was electrical... but I find it rather odd that something would make that much of a noise (with force) and not have the power go out (or a fire). I am a believer in paranormal circumstances... but like others have said, that long ago we can all only guess. I can't imagine plumbing having anything to do with that.

hauntinghelper

Yes you hit the nail on the head there bud
The power of the noise something should have stopped working or broken but this was not the case and the brass ashtrays should have just dropped to the floor but or no they flew to otherside of the room!
It didn't happen once but I can recall 5 times in a 1 year period.
I was looking at the ceiling thinking why is there no damage
Its baffled me ever since.

When logic fails, you may have to be open to more outside the box explanation. I have come to neither believe nor disbelieve in the paranormal, as anything is possible when you have no understanding of what's actually happened (ing)

I agree talaniman. It's not the first suggestion I like to jump to... but it very well could be a supernatural explanation. Who knows. Interesting experience anyway!

I could not see the attachments, they are no longer available is the message. I'll Google. Out of curiosity though, do you still have access to this building or are the keys no longer available to the family? It is always nice to meet the new owners of such a place and see how they like the place, sometimes in those conversations when you are reminiscing, when something has happened and it sticks with them too, it may come up. Never hurts to talk to new people, anyway, just a thought.