Base building or base build indicates the construction/development work done by any developer for creating the base components/elements of the structure. Once the building is rented out to tenants, they have the responsibility for the interior fit-outs.
Base building systems indicate electrical, mechanical, and plumbing systems of buildings, along with HVAC units, exterior, structural components, and fire safety measures of buildings. It also means the construction work that is done for the foundation and basic components of any building. Occupants will hold the responsibilities for interior fit-outs.
This is the portion of a building with multiple tenants that directly affects everyone, including the base/primary structure, the lobby, elevator, hallway, stairwell, primary systems like water supply, electricity, telephone lines, HVAC systems, and so on. These are the structural parts and their equipment within the core of the building, which impact every occupant. It may also mean handing over the base building with completed construction to buyers/tenants, who will take care of the fit-outs for the interiors. There are varying meanings of the term in the real estate sector.