Q: I have a den above a garage in a soft-story house. I am considering a floor-to-ceiling bookcase and a baby grand piano. The piano will weigh 800 to 1,000 pounds. As for a wall of books, I have no idea how much that would weigh. Do you see the need for some kind of reinforcement so it won't sag the floor, etc.?
A: Putting that much extra weight in the den will stress the framing below, especially on a soft-story structure, which has ground-floor space located where a wall might otherwise be. This makes the building's frame prone to twisting and buckling in an earthquake.