Is $50k to convert a bedroom into a home office (recessed wall to storage closet, doorway, recessed lights) an asset or expense? Does not logically increase home value.

I paid a contractor $50k to convert a bedroom in my home into my home office. Scope included converting a recess in the wall into a closet, a new door to the backyard for clients, recessed lights, etc. Should I record this cost as an asset or expense? It's more like repairs/maintenence than it is a building improvement (at least per my city's property tax guidelines). Wouldn't it be odd to record this as a business asset but not an improvement to the book value of my home asset in city records, being the same property?