1Maintenance and repairs are incidental costs that keep a property in ordinary working condition.
2Additions and alterations to property outside the structure include walks, driveways, walls, fences, pools, garages, sheds, etc.
3Additions refer to actual enlargements of the structure.
4Alterations refer to changes or improvements made within or on the structure.
5Major replacements are relatively expensive and are not considered repairs and include furnaces, boilers, roof replacement, central air conditioning, etc.
Source: Bureau of the Census, Department of Commerce