It may be a dumb question, but I don't know the answer so I'll ask it anyway.
I'm planning on building floor-to-ceiling bookshelves completely covering one wall (at least). The room is currently carpeted, subject to change to hardwood in the future.
Do I build these shelves directly on the carpet, or do I go to the subfloor and trim the carpet to match?
If it were a hardwood floor, same question: on top of the hardwood or not?