What is excavationin construction?

Excavation removes soil to reach a required depth or elevation, and it is priced by volume in bank cubic yards. Grading shapes what remains to the design elevations and slopes on the grading plan, and it is usually priced by area. On most sites they run together: the excavator makes the bulk cut, then dozers and graders trim the surface to grade. Estimators carry them as separate line items because the units, equipment, and production rates differ.

Because soil expands when you dig it. A bank cubic yard, the undisturbed in-place volume, swells into roughly 1.25 loose cubic yards for common earth once excavated (the exact factor depends on the soil). The drawings define the in-place volume to be removed, so the pay quantity is bank measure, while trucking gets sized off the swelled loose volume. Mixing the two states is one of the most common earthwork estimating errors.

Under OSHA's excavation standard, a trench 5 ft deep or more requires a protective system such as sloping, shoring, or a trench box, unless the cut is entirely in stable rock. Trenches 4 ft or deeper also need a ladder, ramp, or other egress within 25 ft of workers. Estimators should carry protection costs on any deep dig, because a competent person on site, not the bid, makes the final call.