Special trade contractors primarily engaged in excavation work and digging foundations, including digging and loading. Contractors in this industry may also perform incidental concrete work. Contractors primarily engaged in concrete work are classified in Industry 1771; and those primarily engaged in trenching or in earth moving and land clearing not related to building construction are classified in Major Group 16.
- Excavation work-contractors
- Foundation digging (excavation)-contractors
- Grading: except for highways, streets, and airport runways-contractors