Start With the Recommendations, Then Read the Logs
The earthwork or site preparation recommendations section is where most of the cost lives. Read it first. Then read the boring or test pit logs, because the recommendations tell you what the engineer wants and the logs tell you what you'll actually be digging in.
1. Over-Excavation Depth
Look for how deep to remove and replace below building pads, footings, slabs, and pavements. These are often different numbers. It might be measured below existing grade, below finished grade, or below the bottom of footing, and that reference changes the quantity. A 12-inch vs. 24-inch over-ex across a large pad is a big swing in cubic yards, equipment hours, and water.
2. Lateral Limits
Over-ex rarely stops at the building line. Reports commonly require the removal to extend a set distance beyond the footprint or footing edge. That extra perimeter adds up fast, and it's one of the most commonly missed quantities.
3. Compaction and Moisture
Note the required relative compaction and the test method (for example, a percentage of maximum dry density by ASTM D1557 or D698), plus the moisture range. Tight moisture windows on clay mean more water, more discing, and slower production. Compaction specs that differ by area change the effort.
4. Unsuitable and Expansive Soils
Watch for language about soils that are unsuitable for reuse as structural fill: organics, high-plasticity clay, collapsible soils, debris, or undocumented fill. Anything that can't go back in has to be exported, and something has to be imported to replace it.
5. Import Fill Requirements
Structural fill specs usually limit plasticity, particle size, and gradation. Check whether local borrow meets the spec or whether you're buying a manufactured material and trucking it.
6. Rock, Caliche, and Excavatability
Boring logs showing refusal, cemented layers, or rock tell you about equipment and production. Some reports comment on ripability directly. If trenches or footings go into it, that's a price and schedule item, not a footnote.
7. Groundwater
Depth to groundwater drives dewatering, trench stability, subgrade support, and whether wet soils need drying or stabilization. Check the date the borings were drilled; seasonal groundwater can be higher.
8. Shrink, Swell, and Bulking
Some reports include estimated shrinkage or bulking factors for converting between bank and compacted volumes. If they're there, use them in the balance. If they're not, the estimator has to make and document an assumption.
9. Pavement Sections
Compare the geotech pavement section recommendations with the civil plans. When they don't match, you need an RFI or a clarification in the scope letter.
Carry It Into the Bid
Every requirement above should show up as a quantity, a production assumption, or a line in the scope letter. That's how earthwork estimating is done at Earthworks NV, and it's one of the first things we check on every estimate.