Special trade contractors primarily engaged in the erection of structural steel and of similar products of prestressed or precast concrete.
- Building front installation, metal-contractors
- Concrete products, structural precast or prestressed: placing of-
- Concrete reinforcement, placing of-contractors
- Curtain wall installation-contractors
- Elevator front installation, metal-contractors
- Iron work, structural-contractors
- Metal furring-contractors
- Steel work, structural-contractors
- Storage tanks, metal: erection-contractors
- Store front installation, metal-contractors