A capital improvement refers to any permanent structural change or restoration that adds value to a property, increases its usefulness or adapts it for new purposes. These improvements are usually significant upgrades, such as renovations or structural alterations. Capital improvement projects often seek state reimbursement grants. It can be used to describe the new building construction projects like the New Westhill High School and the New Roxbury K-8 school but it can also be smaller projects.

Other examples of capital improvements include adding new rooms, replacing flooring, installing new HVAC systems, addressing accessibility, and upgrading electrical systems. In municipalities, capital improvements are often made to existing buildings to improve their functionality, longevity, and aesthetics.