Work performed at a construction site in erecting buildings and structures. Construction work may be general or specialized. General construction work is classified according to the materials being used or processed or according to the structures being built as reinforcement placement, concreting, earthwork, masonry, roofing, finishing, carpentry, piling work, erection and installation, and other types. Specialized work includes waterproofing, heat insulating, sanitary-engineering work, and electrical installation work. Some construction work is designated according to the parts or components of the buildings and structures being erected, for example, cribbing, furnace work, and flooring, or according to environmental characteristics, for example, winter work, underground work, and underwater work.