There is an obvious answer to the question of when a building is finished: when the work is complete. But I’m not sure a building is ever really finished. Construction may stop, the contractor leaves, the architect signs off the project and the occupants move in. For a brief period the building can appear complete: everything is new, the surfaces are untouched and the original design is still easy to read. Then it starts to change. Furniture arrives, pictures go on walls, plants grow, rooms begin to be used differently from how they were imagined, storage appears where none was planned, and the garden starts to mature. The building begins to respond to the people using it.
That is not necessarily a loss of the original architecture. It is simply what happens when architecture becomes part of everyday life. Buildings are often presented as finished objects, particularly when they are newly completed, but unlike most objects they are expected to remain useful for decades, sometimes centuries. During that time their occupants, technologies and functions will change. A family home might be altered as children arrive, grow up and eventually leave. A workspace might be reorganised several times as the way people work changes. Extensions are added, walls removed, heating systems replaced, windows changed and gardens redesigned. Some of these changes are substantial, others are so gradual that they are barely noticed, but either way the building is never quite the same.
Even without deliberate alteration, time changes architecture. Timber silvers, metal oxidises, brickwork darkens, concrete stains, and trees grow until they begin to obscure elevations that were once completely visible. What looked finished on the day of completion was really only one stage. Perhaps it makes more sense to think of a building as something transient: not temporary, but continually adjusting to the needs of its inhabitants and its surroundings.
This becomes particularly interesting in architectural photography. A photograph can make a building appear fixed. The image records a particular arrangement of furniture, a particular season, a particular quality of light and a particular stage in the life of the building. That moment can easily become the way the project is remembered, but it is only a moment. Photograph the same building five years later and it may tell a different story. The architecture will still be there, but occupation, weathering and adaptation will have become part of it. Neither version is necessarily more truthful. One records intention more clearly, the other records what has happened since. Perhaps that is the difficulty with the idea of a finished building: completion suggests an end point, when architecture is really the beginning of a much longer process. The drawings are completed. Construction finishes. The photographs are made. The building carries on.