Want to add 10' x 10' bookcase in room. Wall that bookcase would sit on is parallel to floor joists. Floor joists are 2x10 crossing 16' span. Access beneath floor is difficult as it would require messing with ducts, pipes, etc. Worried that joists are not strong enough to support bookcase's added weight. Could send beam across span above bookcase and hang it from that. Would be a lot of work and would prefer someone to tell me that floor should support bookcase.
In most cases, the floor SHOULD handle it just fine. The edges are supported by rim joists or sill plates and should hold that weight easily enough. I'd add some screw-in support along the back of the case to the wall studs for tip stability/security as well.
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