● Blue = What we use
Estimating, calculations, and processes for underground utility and civil work
● Blue = What we use
We specialize in underground utilities and civil work. Typical scope includes:
Quantities are typically measured in linear feet, sizes/diameters, depths, and areas for surface work.
Before estimating comes business development — finding and securing the right opportunities to bid.
Most public work is posted online. Key resources:
Set up alerts and check regularly. Public work has defined timelines and clear bid requirements.
Most private work comes through relationships. Building a network takes time:
Lunches, site visits, and staying in touch keep relationships warm. People work with people they trust.
An area we need to improve. Marketing efforts that help:
Word of mouth and reputation drive most of our leads. But intentional marketing would help expand reach.
Keeping track of what's in the pipeline:
Organized tracking prevents missed opportunities and helps improve hit rate over time.
A streamlined 7-phase approach that moves from opportunity assessment through field handoff.
Before committing to a bid, we evaluate the opportunity and our capacity to execute. Key questions:
Relationships and trust factor heavily into bid/no-bid decisions. Funding verification is critical — it's one of the first red flags we look for. We try to bid strategically so projects don't have massive overlaps where resources compete.
Strong subcontractor relationships are essential. Building and maintaining those relationships (even simple gestures like holiday cards) matters for when we need to grow capacity.
Before diving into detailed takeoffs, we gather the information that will affect everything downstream:
Understanding what you're digging into matters — soil conditions, rock, water table, and access issues all affect production rates, equipment selection, and risk pricing. Getting this information upfront prevents rework later.
This is where the detailed measurement work happens. With site conditions understood and clarifications in hand, takeoffs are more accurate:
Having a clear direction from the information gathering phase makes everything here more accurate and reduces rework.
With quantities in hand, we build out the full cost picture:
Capturing more production data from completed jobs is an ongoing goal — the more historical data, the more accurate future estimates become.
After the bid is built, we go through it with a fine-tooth comb. This is a dedicated review session:
Field staff validate what estimators assume. Their reality check on production rates and installation approach is critical — especially on larger or complex jobs.
Final push to get the bid out the door:
For smaller jobs that come in last-minute, we evaluate capacity and go after them if we can — historically we've done well on small jobs.
After award, we hold another estimating meeting to re-evaluate and make sure nothing was missed. If everything checks out:
The goal is to set up the field team for a successful start with production from day one. A clean handoff means the field isn't inheriting estimating's assumptions without context.
Cubic Yards (CY) = Length (ft) × Width (ft) × Thickness (ft) ÷ 27
Shortcut for slabs (thickness in inches):
CY = Square Feet × Thickness (inches) ÷ 324
| Thickness | CY per 1,000 SF |
|---|---|
| 4" | 12.35 |
| 5" | 15.43 |
| 6" | 18.52 |
| 8" | 24.69 |
| 10" | 30.86 |
| 12" | 37.04 |
PSI = Pounds per Square Inch of compressive strength at 28 days.
| PSI Rating | Typical Use | Mix Characteristics |
|---|---|---|
| 2000 PSI | General fill, non-structural, lean concrete | Low cement content, economical |
| 2500 PSI | Light-duty slabs, foundations in good soil | Minimum for most structural work |
| 3000 PSI | Sidewalks, driveways, residential slabs | Standard residential/light commercial |
| 3500 PSI | Commercial slabs, moderate loads | Common commercial spec |
| 4000 PSI | Structural concrete, beams, columns, heavy slabs | Standard structural specification |
| 4500 PSI | Heavy structural, pre/post-tensioned | Higher cement, lower water/cement ratio |
| 5000+ PSI | High-performance, industrial, bridges | Specialty mixes, additives |
| Type | Approx. CY per 100 LF |
|---|---|
| Standard Vertical Curb (6" × 18") | 3.0 |
| Rolled/Mountable Curb | 2.5 |
| Integral Curb & Gutter (24" wide) | 4.0 - 4.5 |
| Valley Gutter (24" wide × 6") | 4.5 |
Calculate from actual cross-section dimensions when available.
Tons = Area (SF) × Thickness (inches) × Asphalt Weight (lbs/CF) ÷ 2000 ÷ 12
Hot Mix Asphalt (HMA) weighs approximately 145-150 lbs per cubic foot.
Tons = SF × Thickness (inches) × 0.0604
Even simpler (industry rule of thumb):
Tons = SF × Thickness (inches) × 0.055 to 0.06
| Thickness | Tons per 1,000 SF | Notes |
|---|---|---|
| 1" | 6.0 | Thin overlay |
| 1.5" | 9.1 | Surface course |
| 2" | 12.1 | Standard overlay |
| 2.5" | 15.1 | Thicker surface |
| 3" | 18.1 | Full-depth patch |
| 4" | 24.2 | Heavy duty |
| 6" | 36.3 | Base course or full-depth |
1 SY = 9 SF
Tons per SY per inch ≈ 0.055
Example: 5,000 SF of 2.5" asphalt
5,000 × 2.5 × 0.06 = 750 tons (approximately)
Same calculation - what goes in is approximately what comes out.
Removal Tons = SF × Existing Thickness (inches) × 0.055 to 0.06
Notes:
CY = Length (ft) × Width (ft) × Depth (ft) ÷ 27
CY = Length × [(Top Width + Bottom Width) ÷ 2] × Depth ÷ 27
| State | Definition | When It Applies |
|---|---|---|
| Bank (In-Place) | Soil in its natural, undisturbed state | Measuring what's in the ground |
| Loose | Soil after excavation, expanded | Hauling, stockpiling |
| Compacted | Soil after placement and compaction | Fill, backfill, embankment |
When you dig soil, it expands. This is "swell."
| Material | Swell Factor | Loose CY per Bank CY |
|---|---|---|
| Sand | 10-15% | 1.10 - 1.15 |
| Loam / Topsoil | 15-25% | 1.15 - 1.25 |
| Common Earth | 20-30% | 1.20 - 1.30 |
| Clay | 30-40% | 1.30 - 1.40 |
| Rock (blasted) | 50-80% | 1.50 - 1.80 |
Formula:
Loose CY = Bank CY × (1 + Swell %)
Example: 100 CY bank measure of clay (35% swell)
Loose CY = 100 × 1.35 = 135 CY to haul
When you place and compact fill, it shrinks below loose volume.
| Material | Shrink Factor | Compacted CY per Loose CY |
|---|---|---|
| Sand | 10-15% shrink | 0.85 - 0.90 |
| Gravel | 10-12% shrink | 0.88 - 0.90 |
| Common Earth | 10-15% shrink | 0.85 - 0.90 |
| Clay | 15-20% shrink | 0.80 - 0.85 |
For ordering import material:
Loose CY Needed = Compacted CY Required ÷ (1 - Shrink %)
Example: Need 100 CY compacted fill (15% shrink)
Loose CY = 100 ÷ 0.85 = 118 CY to order
| Material | Tons/CY (Bank) | Tons/CY (Loose) |
|---|---|---|
| Sand (dry) | 1.35 - 1.45 | 1.10 - 1.20 |
| Sand (wet) | 1.50 - 1.70 | 1.25 - 1.40 |
| Gravel | 1.40 - 1.55 | 1.15 - 1.30 |
| Crushed Stone | 1.45 - 1.60 | 1.20 - 1.35 |
| Road Base (ABC) | 1.50 - 1.65 | 1.25 - 1.40 |
| Topsoil | 1.10 - 1.25 | 0.90 - 1.05 |
| Clay | 1.50 - 1.80 | 1.15 - 1.40 |
| Native Soil (avg) | 1.25 - 1.40 | 1.00 - 1.15 |
How much to order:
Tons = Compacted CY Required × Weight (tons/CY) × (1 + Shrink Factor)
Example: Need 200 CY compacted road base
Tons = 200 × 1.55 × 1.15 = 356 tons to order
Volume:
Backfill CY = Trench Volume - Pipe Displacement - Bedding Volume
Pipe Displacement (CF per LF):
| Pipe Diameter | CF per LF |
|---|---|
| 4" | 0.087 |
| 6" | 0.196 |
| 8" | 0.349 |
| 12" | 0.785 |
| 18" | 1.767 |
| 24" | 3.142 |
Bedding: Typically 4-6" below pipe, pipe zone to springline, and initial backfill to 12" above pipe.
CY = Length (LF) × Width (ft) × Depth (ft) ÷ 27
| Pipe Size | Minimum Trench Width | Notes |
|---|---|---|
| 4" - 8" | 24" | Or pipe OD + 12" |
| 10" - 12" | 30" | Or pipe OD + 18" |
| 15" - 18" | 36" | Or pipe OD + 18" |
| 24"+ | Pipe OD + 18" min | Per spec requirements |
Given: 500 LF of 8" water line, 5' deep, 30" wide trench
Excavation CY = 500 × 2.5 × 5 ÷ 27 = 231 CY
With 25% swell for hauling:
Loose CY = 231 × 1.25 = 289 CY
| Structure | Typical Depths | Material |
|---|---|---|
| Sewer Manhole | 4' - 20'+ | Precast concrete |
| Water Valve Box | Surface - 6' | Cast iron, concrete |
| Pull Box (Electrical) | 18" - 36" | Polymer or concrete |
| Vault (Telecom) | 3' - 6' | Precast or polymer |
| Catch Basin | 3' - 8' | Precast concrete |
Total LF = (Length ÷ Spacing + 1) × Width + (Width ÷ Spacing + 1) × Length
| Bar Size | Diameter | Weight (lbs/LF) |
|---|---|---|
| #3 | 3/8" | 0.376 |
| #4 | 1/2" | 0.668 |
| #5 | 5/8" | 1.043 |
| #6 | 3/4" | 1.502 |
| #7 | 7/8" | 2.044 |
| #8 | 1" | 2.670 |
| #9 | 1-1/8" | 3.400 |
| #10 | 1-1/4" | 4.303 |
Bars running 50' direction:
(30 ÷ 1 + 1) = 31 bars × 50' = 1,550 LF
Bars running 30' direction:
(50 ÷ 1 + 1) = 51 bars × 30' = 1,530 LF
Total:
3,080 LF × 0.668 lbs/LF = 2,057 lbs of #4 rebar
| Calculation Type | Primary Tool | Verification |
|---|---|---|
| Area/Length measurement | Construction Takeoff | Bluebeam |
| Volume calculations | Excel / HCSS | Manual check |
| Material quantities | HCSS Bid Items | Takeoff cross-ref |
| Tonnage conversions | Excel formulas | Reference tables |
| Cost extension | HCSS | Spreadsheet backup |
| Pipe Size | Sand Bedding (CF/LF) | Crushed Stone (CF/LF) | Notes |
|---|---|---|---|
| 4" - 6" | 0.5 - 0.75 | 0.4 - 0.6 | 6" bedding depth |
| 8" - 10" | 0.75 - 1.0 | 0.6 - 0.8 | 6" bedding depth |
| 12" - 15" | 1.0 - 1.5 | 0.8 - 1.2 | 6" bedding depth |
| 18" - 24" | 1.5 - 2.5 | 1.2 - 2.0 | 6-8" bedding depth |
| 30"+ | 2.5 - 4.0 | 2.0 - 3.2 | 8" bedding depth |
Bedding CY = Length (LF) × Bedding Width (ft) × Bedding Depth (ft) ÷ 27
Width: Pipe OD + 12" min | Depth: 6" below invert to springline
CY = π × (ID/2)² × Height (ft) ÷ 27
| Inside Diameter | Wall Thickness | CY per Foot Height |
|---|---|---|
| 48" | 5" | 0.70 |
| 60" | 6" | 1.10 |
| 72" | 7" | 1.60 |
| 96" | 8" | 2.85 |
Risers = (Total Depth - Base - Cone) ÷ 1.0 ft
Standard: 12" tall rings
Steps = (Depth - 2') ÷ 1.0 ft × 2
12" spacing, offset pattern
Gaskets = Number of Joints
Typically one gasket per joint
| Pipe Material | Standard Length | Joints per 100 LF |
|---|---|---|
| Ductile Iron | 18' - 20' | 5 - 6 |
| PVC | 20' | 5 |
| HDPE | 40' - 50' | 2 - 3 |
| Concrete | 8' | 12 - 13 |
| RCP | 8' | 12 - 13 |
Count from plans: Elbows, tees, reducers, flanges, end caps
Gallons = Pipe ID (inches)² × Length (feet) × 0.0408
Add 10-20% for filling, purging, and test pressure
| Utility Type | Test Method | Typical Pressure | Duration |
|---|---|---|---|
| Water | Water pressure test | 150 PSI (1.5× operating) | 2 hours minimum |
| Gas - Low Pressure | Air pressure test | 3-5 PSIG | 24 hours |
| Gas - High Pressure | Hydrostatic (water) or air | 1.5× operating pressure | 24 hours |
| Gas - Distribution | Air pressure test | 50-100 PSIG | 24 hours |
| Sewer - Gravity | Water infiltration test | Head pressure | Per spec |
| Sewer - Force Main | Water pressure test | 1.5× operating | 2 hours |
| Storm Drain | Visual inspection or water test | N/A or head pressure | Per spec |
Example 1: 1,000 LF of 8" water line
8² × 1,000 × 0.0408 = 2,611 gallons
Add 20% = 3,133 gallons total
Example 2: 500 LF of 12" sewer force main
12² × 500 × 0.0408 = 2,938 gallons
Add 15% = 3,379 gallons total
Ideal conditions, 50-minute hour
| Excavator Size | Loose CY/Hour | Bank CY/Hour | Notes |
|---|---|---|---|
| Mini (1-3 CY) | 15 - 25 | 12 - 20 | Tight spaces, shallow |
| Small (3-5 CY) | 40 - 60 | 32 - 48 | Standard utility work |
| Medium (5-8 CY) | 80 - 120 | 64 - 96 | Deep trenches, large pipe |
| Large (8-12 CY) | 150 - 220 | 120 - 176 | Mass excavation |
| Pipe Size | LF/Day (Crew of 3-4) | Factors |
|---|---|---|
| 4" - 6" | 200 - 400 | Small, fast handling |
| 8" - 12" | 150 - 300 | Standard utility size |
| 15" - 18" | 100 - 200 | Heavier, slower |
| 24" - 30" | 50 - 100 | Requires larger equipment |
| 36"+ | 25 - 75 | Heavy equipment, careful placement |
| Equipment | SF/Hour | CY/Hour |
|---|---|---|
| Plate Compactor | 200 - 400 | N/A |
| Jumping Jack | 100 - 200 | N/A |
| Vibratory Roller | 1,000 - 2,000 | 50 - 100 |
| Sheepsfoot Roller | 800 - 1,500 | 40 - 75 |
Rates vary by soil conditions, depth, access, weather, and crew experience. Use historical data when available.
| Truck Type | Loose CY Capacity | Tons Capacity | Notes |
|---|---|---|---|
| Single Axle | 8 - 12 | 10 - 15 | Small jobs, tight access |
| Tandem Axle | 12 - 18 | 15 - 22 | Standard dump truck |
| Tri-Axle | 18 - 22 | 22 - 28 | Larger loads |
| End Dump (Semi) | 20 - 25 | 25 - 30 | Mass hauling |
| Bottom Dump | 25 - 30 | 30 - 35 | Spreading applications |
Cycle Time = Load Time + Haul Time + Dump Time + Return Time
Trucks = (Production Rate CY/Hour × Haul Time Hours) ÷ Truck Capacity CY
Example: Excavating 100 CY/hour, 30-minute round trip, 18 CY trucks
Trucks = (100 × 0.5) ÷ 18 = 2.8 trucks (round up to 3)
SF = Trench Width (ft) × Length (ft) + Overlay
Overlay: Extend 6-12" beyond trench edges
Thickness: Surface 1.5-2", Base 2-4" (if needed), or match existing
For concrete surfaces:
CY = SF × Thickness (inches) ÷ 324
For grass areas:
| Trench Width | Typical Restoration Width |
|---|---|
| 24" - 30" | 36" - 48" |
| 36" - 48" | 48" - 60" |
| 60"+ | Trench width + 12" each side |
Gallons = Area (SF) × Depth (ft) × 7.48
GPM needed based on water table and infiltration:
| Application | Typical GPM | Pump Size |
|---|---|---|
| Small trench (4-8" pipe) | 10 - 30 | 2" - 3" pump |
| Medium trench (12-18" pipe) | 30 - 75 | 3" - 4" pump |
| Large trench (24"+ pipe) | 75 - 150 | 4" - 6" pump |
| Manhole/vault excavation | 20 - 50 | 3" - 4" pump |
| Mass excavation | 100 - 300+ | Multiple pumps |
For deeper excavations or high water tables:
Required during excavation, pipe installation, and backfill (if water table high)
LF = Work Length + Taper Length + Buffer
| Speed Limit | Taper Length |
|---|---|
| 25 mph | 100' |
| 35 mph | 150' |
| 45 mph | 200' |
| 55 mph | 300' |
Required for work in roadway, lane closures, sidewalk closures, intersection work
| Type | Description | Method |
|---|---|---|
| Riprap | Loose rock, can be ripped | Ripper attachment |
| Soft Rock | Can be excavated with hoe ram | Hoe ram, breaker |
| Hard Rock | Requires drilling/blasting | Drill & blast |
Requires specialty subcontractors and permits. Rates vary by rock type, depth, and access.
| Material | Formula | Notes |
|---|---|---|
| Concrete | CY = SF × inches ÷ 324 | Add 5-10% waste |
| Asphalt | Tons = SF × inches × 0.055 | Standard HMA |
| Excavation | CY = L × W × D ÷ 27 | Bank measure |
| Import fill | Tons = CY × 1.5 × 1.15 | Avg weight + shrink |
| Backfill | CY = Trench - Pipe - Bedding | Add compaction factor |
Don't cut corners. Estimating is scrupulous, highly detailed work with a lot of moving parts. Data needs to be captured accurately, analyzed, cross-referenced, and checked. Cutting corners always comes back to bite you. You can't wing it.
Andrew and I lead the estimating efforts, with support from project managers, superintendents, and our operations manager as needed. The goal is to grow this process — better data capture, stronger subcontractor relationships, and more involvement from field leadership on larger bids.