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Master
Earthwork
Estimating
A complete interactive course covering site preparation, soil analysis, quantity takeoff, foundations, paving, and landscaping — with live calculators and a practice quiz.
What You Will Learn
Soil & Rock
Classify soils, understand swell factors, angle of repose, and how soil type drives equipment selection and excavation cost.
Quantity Methods
Master the cross-section and average end-area methods to calculate excavation volumes from site plan data.
Foundations & Piles
Differentiate driven vs. bored piles, calculate concrete volumes for pile caps and caissons, and read foundation drawings.
Site Methods
Understand demolition, shoring, soil stabilization, dewatering, and utility installation — and how each affects the bid.
Pavement
Estimate concrete and asphalt pavement volumes, subbase quantities, curb linear feet, and reinforcement.
Landscaping
Take off irrigation linear feet, lawn areas, trees and shrubs, fencing, and site amenity costs from landscape plans.
Site Preparation Materials
Before any work begins, the estimator must understand what exists at and below the ground surface. These materials and their properties directly drive project cost.
Soil Classification
Soil is classified into four primary types based on how easily it can be loosened and moved. This classification determines equipment selection and excavation cost.
⬇ SOIL PROFILE — Difficulty & Equipment Required
Angle of Repose
| Soil Type | Dry | Moist | Wet | Estimating Note |
|---|---|---|---|---|
| Sand | 20–35° | 30–45° | 20–40° | Wide slope — more material removed |
| Earth | 20–45° | 25–45° | 25–30° | Highly variable; verify conditions |
| Gravel | 30–48° | — | — | Relatively stable when dry |
| Gravel/Sand/Clay | 20–37° | — | — | Use conservative (lower) angle |
Soil Swell
| Soil Type | In-Place | After Excavation | Swell |
|---|---|---|---|
| Earth clay | 100 | 125 | +25% |
| Sand & gravel | 100 | 150 | +50% |
| Broken stones | 100 | 150 | +50% |
| Rock | 100 | 150 | +50% |
Rock Classification & Other Materials
Soft Rock
Example: Shale. Often removable with heavy equipment alone. Lowest rock removal cost.
Medium-Hard Rock
Example: Slate. May need specialized equipment or light blasting. Moderate additional cost.
Hard Sound Rock
Example: Schist, metamorphic bedrock. Almost always requires drilling and blasting. Highest removal cost.
Geotextile
Synthetic fabric stabilizing soil on slopes. Applied after rough grading. Diverts groundwater and controls erosion.
Hazardous Materials
Risk to health/safety/property. Remediation required — licensed contractors, special equipment, legal disposal. Major cost addition.
Soil Amendments
Materials (clay, slurry, local fill) added to soil to increase compaction and maintain desired angle of repose.
Site Preparation Methods
Site preparation involves a planned sequence of operations transforming raw land into a construction-ready site. Each operation has specific estimating cost items.
Subsurface Investigation
Soil engineers drill test borings and analyze samples. Geotechnical report describes subsurface materials. Provides live/dead load bearing data. Cost items: number, depth, diameter of holes, rock/soil type analysis.
Clearing and Grubbing
Removal of vegetation and obstacles from the site. Cost basis: per acre (or hectare metric). Items include removal equipment, labor, disposal, and temporary erosion control (straw bales, silt fence).
Demolition
Organized destruction of existing structures. Cost items: heavy equipment, labor, truck loading/hauling, dumping fees, overhead. Hazardous material check required — asbestos and lead paint add major regulated disposal costs.
Groundwater Management — Dewatering
Well points — perforated pipes driven and pumped to lower the water table. Cost items: driving well points, installing/maintaining pipes, fueling pumps, labor, and removal of the temporary system.
Shoring
Temporary support system for excavation walls. Required for unstable soil, deep excavations, nearby structures. Must meet OSHA 1926 Subpart P. Cost items: linear feet, type and strength, excavation depth.
Site Utility Installation
Storm sewers, sanitary sewers, water, gas, electrical, telephone. All must be installed before foundations and streets. All existing utilities must be located first with color-coded flags. Cost basis: linear feet of trenching.
Shoring Types
Trench Boxes
Reinforced wood or metal assembly set into excavation by crane to prevent cave-in. Used for small excavations. Costs include ownership/rental and crane installation.
Sheet Piles
Interlocking vertical steel supports driven into ground. Forms continuous wall retaining horizontal earth thrust. Multiple designs: Z, U, flat, arch, ball and socket, double jaw, and others.
Grouting / Slurry
Cementitious grout pumped into adjoining areas or shot onto surface of banks after excavation. Holes drilled prior to excavation and filled with grout or slurry before digging begins.
Cofferdams
Watertight enclosures of sheet piles driven to form interlocking cells. Used for below-water construction — bridges, dams. Material inside the cell removed to allow worker access.
Earthwork Quantity Takeoff
The estimator turns site plan elevations into cubic yard quantities using two primary calculation methods. One cubic yard equals 27 cubic feet — the most important conversion in earthwork.
Method 1 — Cross-Section Method
Used when the excavated area is roughly square or rectangular. Four corner elevations calculate an average depth, then multiplied by grid area.
Depths: A=10.35, B=14.52, C=6.78, D=4.63 → Avg = 9.07′
V = 5,625 × 9.07 = 51,019 cu ft ÷ 27 = 1,889.6 cu yd
Method 2 — Average End-Area Method
Used when the sides of the excavation are irregularly shaped and not parallel. Calculate area at each end, average them, multiply by length.
Avg = 45 sq ft | V = 50 × 45 = 2,250 cu ft ÷ 27 = 83.33 cu yd
Key Excavation Terms
🔄 Overdig
Excavation beyond building dimensions to provide worker space for setting forms, tying rebar, and waterproofing. Must be backfilled at completion.
🔙 Backfilling
Replacing soil around subsurface structures after construction. Free of large boulders. Backfilled areas must be compacted per specification requirements.
📏 Payline
The exact excavation line for which the contractor is responsible — defined precisely in specifications (e.g., “2 ft from top edge of footing, then slope per OSHA”).
⛰️ Slope Cut
Inclined wall excavation used in soft, shifting soil. Angle determined by angle of repose for the soil type per OSHA safety guidelines.
🔧 Trencher
Machine with toothed conveyor system digging narrow (8″–12″) grooves for utility line installation — pipe trenches, electrical conduit, etc.
🪵 Cradling
Temporary support of existing utility lines in or around an excavated area — timbers jacked up as excavation deepens to keep lines at original level.
Gridding for Cut and Fill
Gridding divides a topographic site map into small squares (25’×25′ or 100’×100′) for cut and fill calculations. A contour line — dashed (existing grade) or solid (finished grade) — provides elevation at each corner. Cut = negative (material removed). Fill = positive (material added). The zero line connects points where existing and planned elevations are equal. Total cut or fill value × excavation cost per cubic yard = total cost.
Foundation Materials and Methods
Any structure that cannot be fully supported by surface soil requires a footing and foundation system to transfer loads to solid bearing material below grade.
Footing
Supports and distributes structural loads directly to the bearing surface of soil, piles, or rock below. The base that spreads weight over a larger area.
Foundation
Primary support through which all imposed loads are transmitted to footings or earth. Holds the structure in place and provides stability.
Caisson
Large-diameter, cast-in-place concrete pile created by boring a hole and filling it with concrete. Used for deep foundations where soil bearing is poor.
Pile Cap
Large concrete unit placed on top of a pile or group of piles to distribute the structural load across individual piles. Can require many cubic yards of concrete.
Driven Piles vs. Bored Piles
🔨 Driven Piles
Hammered into ground with pile-driving rig
- Pipe pile: Steel pipe; supported by friction; concrete filled after driving
- HP-pile: Steel H-shape (beam); supported by subsurface layer
- Timber pile: Tapered treated poles; metal shoes protect tip in hard strata
- Precast concrete: Square cross-section; all cut off at given elevation
🔄 Bored Piles (Auger Cast)
Drilled into ground, filled with concrete
- Drilled to specified depth and diameter; usually stepped to various diameters
- Reinforcing steel set in place; hole filled with concrete
- Bottom may be belled out for enlarged bearing surface
- Metal sleeves used in unstable areas; removed after concrete placed
Pile Quantity Takeoff
Foundation takeoff depends on materials used and site conditions. Different pile types require specific calculation approaches for depth, volume, and cost.
Bored Pile — Concrete Volume
d = 36/12 = 3 ft | A = 0.7854 × 9 = 7.07 sq ft
V = 7.07 × 56 = 395.9 cu ft ÷ 27 = 14.66 cu yd
Pile Cap — Concrete Volume
V = 150 cu ft ÷ 27 = 5.56 → rounds UP to 6 cu yd
Pile Types — Takeoff Method Summary
| Pile Type | Takeoff Method | Key Cost Factors |
|---|---|---|
| Precast Concrete | Count piles by type & depth | Crane, proper hammer, lead system; transporting, lifting, setting; site accessibility |
| Steel Pipe / HP | Count each length required | Driving method, pile type, depth, site accessibility |
| Timber | Count by diameter & length | Driving method, penetration depth, metal shoe cost for hard strata |
| Vibratory | Bid by soil analysis | Number of piles, depth, diameter of compacted piles |
Pavement & Landscaping Materials and Methods
After the majority of a building is constructed, surrounding areas are finished for access and landscape design. Many local codes require minimum landscaping and green space.
Pavement Types
Cast-in-Place Concrete
- Cement + water + fine and coarse aggregate
- Shallow excavations, formwork, rebar or welded wire fabric reinforcement
- Estimated by cubic yards (material) + square feet (labor)
Asphalt (HMA)
- Dark-colored pitch — crushed stone + bituminous materials
- Placed on compacted limestone/other subbase
- Compacted after placement; striping painted per site plans
- Priced by the ton of material delivered
Pervious Concrete
- Allows stormwater to penetrate and minimize runoff
- Additional costs for subsurface preparation
- Estimator must account for subbase treatment costs
Subgrade / Subbase
- Granular subbase — crushed gravel or sand, spread and compacted
- Stabilization fabric may be required
- Volume in cubic yards → quarry converts to tons
Landscaping Components
| Component | Takeoff Basis | Cost Items |
|---|---|---|
| Lawns | Square feet or acres — sodded, seeded, or natural | Finish grading, surface prep, sod/seed, fertilizer, water, straw for germination |
| Trees & Shrubs | Count by species on plant schedule | Nursery cost per plant (includes planting + staking); spec may require maintenance period |
| Irrigation | Linear feet of each pipe size; count valves + spray heads | Pipe, valves, timers, drains; installed LAST after all heavy construction |
| Fencing | Linear feet of each type | Posts (set in concrete below frost line), rails, fencing material, gates |
| Site Amenities | Item count | Obtained from suppliers as-needed; estimator determines number and type |
Pavement & Landscaping Quantity Takeoff
Area is calculated to determine quantities for subsurface and paving materials as well as labor. Landscaping materials and locations are noted in specifications and site plans.
Concrete Pavement Volume
V = 0.5 × 20 × 140.9 = 1,409 cu ft ÷ 27 = 52.18 cu yd
Asphalt Quantity
Pavement Estimate Checklist
Primary Info Needed
- Type of pavement material
- Exterior dimensions of paved area
- Dimensions of any voids (islands, planters)
- Pavement thickness
- Reinforcement requirements
- Surface finish spec
Subgrade Prep Items
- Spreading granular subbase (CY → tons)
- Stabilization fabric if required
- Compaction of subgrade and structural fill
Curb & Gutter
- Linear feet of each curb type
- Cost per LF: materials + formwork + labor
- Formwork varies with radiuses, curves, aprons
Landscaping Estimate
- Finish grading, sodding, seeding
- Excavation for trees/shrubs
- Specs may include maintenance obligations
- Hydroseeded areas: sq ft of coverage
Earthwork Calculators
Practice the exact calculation methods from the textbook with live calculators. Enter your own values and see full step-by-step solutions.
📐 Cross-Section Method
Calculate excavation volume from four corner elevations of a square/rectangular grid.
📦 Average End-Area Method
For irregularly shaped excavations — enter triangular end dimensions and length.
🔵 Bored Pile Concrete Volume
Calculate concrete required for a cylindrical cast-in-place pile.
📦 Pile Cap Volume
Calculate concrete volume for a rectangular pile cap.
🛣️ Concrete Pavement Volume
Calculate concrete required for a slab — driveway, parking lot, or walk.
Test Your Knowledge
15 questions covering all sections of Chapter 5. Click an answer to see if you are correct and read the explanation.
Key Terms Glossary
All key vocabulary from Chapter 5. Search to filter terms.
Estimator’s Field Checklist
Use this on every earthwork estimate. Click each item to mark it complete.
Work through sequentially on every new earthwork estimate. Each item represents a category of costs or information that, if missed, can result in underbidding or expensive field surprises.
Pre-Bid Investigation
- Obtain and review the geotechnical / soils engineering report
- Identify all soil types present and their classification
- Determine angle of repose — calculate additional excavation quantity needed
- Note groundwater table elevation — determine if dewatering is required
- Check site plans and specifications for any identified hazardous materials
- Identify all rock types — determine if blasting will be required
- Locate ALL existing site utilities; contact utility companies to mark the site
Earthwork Quantities
- Choose calculation method: cross-section (square) or end-area (irregular)
- Calculate total cut and fill quantities using gridding from topographic plan
- Determine overdig required based on soil type and angle of repose
- Apply soil swell factor to calculate actual truck loads for spoil removal
- Compare cut vs. fill — if fill exceeds cut, plan for borrow fill purchase and hauling
- Include dust control and erosion protection costs (silt fence, straw, water spray)
Demolition and Site Prep
- Identify all structures to be demolished; check for hazardous materials
- Calculate clearing and grubbing quantity in acres — include disposal costs
- Identify shoring requirements — verify system meets OSHA 1926 Subpart P
- Calculate site utility excavation in linear feet per utility type
Foundations and Piles
- Identify all pile types from foundation drawings and specifications
- Calculate concrete volume for all bored piles (0.7854 × d² × depth)
- Calculate concrete volume for all pile caps (L × W × H ÷ 27, round up)
- Take off steel reinforcement separately from pile details and rebar schedule
- Include crane costs, pile-driving equipment, leads, and hammers
Pavement, Landscaping, and Overhead
- Calculate pavement area (sq ft) — deduct islands and void areas
- Calculate concrete volume (cu yd) and asphalt quantity (sq ft × depth → tons)
- Calculate subbase volume (cu yd) converted to tons by quarry
- Calculate curb and gutter in linear feet by type
- Take off landscaping: lawn area (acres), tree/shrub count, irrigation LF, fencing LF
- Apply overhead and mobilization (~25%) to appropriate bid items
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