After a deed states that ownership lasts as long as a building is not destroyed, what kind of interest does the original grantor retain?

The situation described involves a deed that specifies ownership of a property is contingent upon the preservation of a building. In this context, the original grantor retains a reversionary estate.

A reversionary estate is a type of interest that allows the grantor to regain ownership of the property under certain conditions, particularly when the specified events outlined in the deed occur. Here, if the building is destroyed, the original grantor would automatically regain ownership, as the terms of the deed indicate that ownership is only valid as long as the building exists.

In contrast, a life estate, while it provides ownership over a property for the duration of someone's life, does not pertain to conditions regarding the property's physical state or condition. Ongoing ownership is not a recognized legal term in property law, making it an inappropriate choice. A fee simple estate denotes the most complete form of ownership in land and does not include conditions that could terminate or revert ownership based on the state of the property. Therefore, it wouldn’t accurately reflect the grantor's retained interest under the circumstances described.