Building improvement costs are costs that materially extend the useful life of a building or increase the value of a building or both. Examples of costs for building improvements are structures attached to a building such as covered patios, sunrooms, garages, carports, etc; installation of heating and cooling systems; structural changes such as reinforcement of floors, walls; replacement of beams, joints, steel grids; exterior renovation such as installation of siding, roofing, and masonry. Examples of what not to include generally are maintenance costs that do not extend the life or improve the value of a building. Examples of what not to include are plumbing and electrical repairs; interior and exterior decoration; exterior maintenance such as replacement of deteriorated siding, roof or masonry sections; cleaning or other periodic maintenance such as repainting both interior or exterior or touch up plastering. Maintenance type costs should be recorded as maintenance expense.