How much weight does wood hold?

Question:We have several boxes - some of books and papers - in our attic, which is reimbraced. I worry sometimes, however, that we have too much up there, since it's pretty crammed in, but the ceiling isn't bowing or anything. How many pounds can a ceiling, or wood, be expected to hold for an extended period of time?

Answers:
Unless you have a pickup truckload up there and packed and stacked very densely, you are probably OK.