The three cubic yards that are not the same cubic yard
Every earthwork quantity is one of three states, and converting between them is not optional:
- BCY — Bank Cubic Yards: the volume of soil as it sits undisturbed in the ground. This is usually what a cut quantity is reported in from the surveyor.
- LCY — Loose Cubic Yards: the same soil after excavation, in a truck bed or stockpile. Bulkier due to swell. This is what you pay the trucker by.
- CCY — Compacted Cubic Yards: the same soil placed and compacted in a fill, at or near the Proctor density. This is what the fill quantity is reported in.
A common mistake: the plan says 42,000 CY of cut and 38,000 CY of fill, "balanced on site." The estimator writes "net 4,000 CY export." That is wrong by a factor that depends entirely on the soil. A clay with a 15% swell and 10% shrink converts as: 42,000 BCY cut yields 48,300 LCY to haul and 37,800 CCY placed. If the fill is 38,000 CCY, you are actually 200 CCY short — meaning you have to import dirt, not export. A 6,000 CY swing in the wrong direction at $14/CY loaded, hauled, and placed is $84,000 you did not bid.
Swell and shrink factors by soil class
USCS and AASHTO classifications drive the swell/shrink numbers. Rough working ranges every sitework estimator should have memorized:
- Dry sand (SW, SP / A-1, A-3): 10–12% swell, 12–15% shrink. Relatively easy to compact.
- Common loam (SM, SC / A-2): 18–25% swell, 8–12% shrink.
- Clay (CL, CH / A-6, A-7): 25–40% swell, 10–15% shrink. Moisture-sensitive, requires moisture conditioning for compaction.
- Rock, shot or ripped: 50–70% swell, variable shrink depending on gradation and fines content.
- Organic topsoil: strip and stockpile separately; do not use as structural fill per AASHTO T99 / ASTM D698.
The geotechnical report — the document the estimator often does not read — states the soil classification and recommended compaction (typically 95% of standard Proctor per ASTM D698 or 95% of modified Proctor per D1557 for structural fills). Without the geotech, you are guessing. With the geotech, the math is mechanical.
Haul distance: the line item that silently blows up
Excavation is priced per BCY. Hauling is priced per LCY per mile or per load per round trip. The two are not interchangeable. A short-haul on-site balance is maybe $3–$5/BCY. A 12-mile off-site export haul to a spoils site, with a 45-minute round trip and $15/ton tipping fee, is $18–$28/BCY. If the surveyor's earthwork report says "net 12,000 CY export" and the estimator prices it at on-site equipment rates, the bid is missing $150,000–$280,000 in trucking.
- Round-trip cycle time: load (3–5 min), haul out, dump (2–3 min), return. A 24-yard articulated dump on a 6-mile haul is 35–50 minute cycle. An off-road 40-ton on a 2-mile on-site pull is 12–18 minutes.
- Spoils or borrow cost: metropolitan clean-fill sites run $8–$22/ton for inbound (export) and $4–$12/ton for outbound (borrow). Contaminated or non-clean loads can spike to $90–$180/ton.
- Permitted haul routes: some jurisdictions restrict truck routes, which adds miles. Chicago, NYC, SF, and Seattle all have restrictions that can add 20–40% to haul distance.
"The earthwork bids I audit that missed by 10% or more — four out of five times the miss is the haul. They bid the cut, they bid the fill, and they put a guess on the haul because they did not map the actual route to the actual spoils site. The map is a half hour of work that can save you a quarter million dollars."
Renée Kovach, Civil Estimating Consultant, former Chief Estimator at two ENR top-100 civil contractors
Strip and stockpile: the line item before the line item
Every earthwork job starts with stripping topsoil. On a 14-acre commercial site with 8 inches of topsoil, that is 14 x 43,560 x 0.667 / 27 = roughly 15,100 BCY of topsoil to strip and stockpile. Labor, equipment, stockpile area, erosion control around the pile, and eventual re-spread at landscape areas all need line items. On jobs I have audited, topsoil strip and re-spread was missed entirely on roughly one in six bids. Recovery is painful because the topsoil strip is on the critical path of the grading schedule.
ALTA survey overlay and the boundary you cannot trust
An ALTA/NSPS survey shows boundary, easements, existing utilities, setbacks, and improvements. Civil grading plans are drawn on site-plan topo that sometimes pre-dates the ALTA. Estimators who do not overlay the ALTA on the grading plan miss:
- Easements that restrict grading or require flowable fill under a utility.
- Existing utilities in the cut area that need to be saved, relocated, or exposed by hand.
- Tree protection zones that change the haul routes and staging.
- Right-of-way dedications that change the effective site area.
A missed existing 12-inch sanitary main in a cut zone is a change order, a delay, and sometimes a lawsuit. The ALTA is the insurance policy against those, and it is free on every job that has one.
Proctor density and the compaction delta
Specified compaction drives equipment selection and passes per lift. 90% standard Proctor under landscape is a light sheepsfoot in 3–4 passes. 98% modified Proctor under structural slabs and pavements is a heavy smooth drum in 6–8 passes with moisture conditioning. The labor/equipment hours for compaction can vary 2.5x between those two. Bidding one when the spec requires the other is the classic "I saw 95%, I didn't see modified vs standard" miss.
What changes when you get it right
A civil earthwork bid that reads the geotech, converts BCY to CCY with the correct soil-specific shrink factor, separates on-site haul from off-site haul at realistic cycle times, carries strip-and-stockpile as a named line, overlays the ALTA against the grading plan, and prices compaction against the specified Proctor and modifier — that bid has a shot at 6–9% net on sitework. Everything else is speculation dressed up as estimating, and the speculators are why civil contractor bankruptcy rates lead every commercial sector.