My wife and I watched this on DVD a number of years ago, and it was relatively recent at the time, which would put it somewhere between 2000 and 2010 or so. I believe it was American.
The setting was a rundown hotel or apartment building. I remember it was a large white building (at least ten stories, probably more), with cinder block hallways and, if I recall, seemingly located in the middle of nowhere.
The story revolved around a mother and her child (I want to say a daughter, but I don't really remember) moving in. The child was around 12 to 15. She goes exploring and meets an older teenager. It gets fuzzier from there.
I believe the teenager leads her to a hidden loft at the top of the building. Later in the movie it's revealed the loft is over a shaft all the way down to the basement. I believe there was also one or more people chained up in the basement (I seem to recall something about a radio, too). The teenager's mother is revealed to be the villain and is killed when thrown down the shaft.