Broadly speaking, it depends! Preservation planners answer this question quite frequently - some answers are best practices, others are legal depending on whether the building is protected by local, state, or national laws.

In Seattle, landmarking typically does not protect the interior of the building. So if a building requires updates to electrical, water, or other systems, those updates can continue to happen after landmarking status. And it should be made clear that Seattle's Landmarks Preservation Board (LPB) always approves safety and ADA updates.

While landmark designation in Seattle always protects the exterior of buildings, they occasionally undergo dramatic changes. The Firestone Tire Building at 400 Westlake Avenue is a two-story terra-cotta clad building to which an gleaming glass office tower has been added. The Seattle Asian Art Museum, a beloved landmark in Volunteer Park, sports a modern addition on its eastern (rear) facade. The Lincoln Mercury and Ford dealerships at 615 Westlake Avenue N. and Mercer Street are side by side landmarks that were totally dismantled, moved eight feet to the north and reconstructed as part of the widening of Mercer Street and the construction of the Allen Institute that sits above and west of them.

When a building is landmarked by the city of Seattle, the .paperwork must describe precisely what is being protected. The LPB staff will discuss with the building owner a set of "controls and incentives" specifying what changes will be permitted in the future. Those changes will be included in the designating ordinance, and all changes must be approved by the LPB (except for minor changes that can be approved by staff).