Building Cost Protection: $15,000 Limit
Usually, if you are in a co-op or condominium, the association that owns the building will have insurance and will pay to rebuild your unit if it is damaged or destroyed in a fire or other accident. But there are reasons you may still want "building cost protection insurance."
First, if something like a fire happens, your association may increase your dues or assess fees to everyone in the building to help pay for repairs or the increased cost of future insurance.
Second, if your association has a "bare walls policy" and there's a fire or other disaster, the association will only pay the costs of repairing damages to the outside of your unit. You will be responsible for everything on the inside, including things like cabinets, plumbing, and bathroom fixtures (which aren't covered by "personal property protection").
Building cost protection would cover up to $15,000 in damages to the inside of your unit.