If you own a condo or co-op and the building starts to degrade, the owners will vote (via an elected board) whether to make repairs to the building. If they vot

If you own a condo or co-op and the building starts to degrade, the owners will vote (via an elected board) whether to make repairs to the building. If they vote to do that, in addition to the apartment, you own your unit's share of the repair bill, which gets passed to you as an assessment. So when you buy the apartment you're buying an obligation to pay for the building's repairs (assuming a majority of the other owners want to keep the building standing as well). If you disagree with everyone else and don't pay the assessment, the other owners (again via the condo board) can put a lien on your property and sell it to cover the amount you owe. If it got really really bad there's probably a situation in which the owners of the building could vote to have it demolished and rebuilt. The take away is that in addition to the apartment itself, you're actually buying shares in a legal entity and get certain rights and obligations as a result of that. It's that entity that owns the building and the land underneath. How exactly the entity is structured depends on whether it's setup as a condominium or cooperative.