👷 Module 5: Labor Estimation
Convert takeoffs into manhours, apply realistic productivity, build composite crew rates, and translate hours into schedule and cost. This is where your estimate becomes field-ready.
📘 Overview
Labor is your largest variable and the easiest place to win or lose a bid. In this module you’ll select labor units, apply productivity factors (height, congestion, phasing, shift), build composite crew rates with burden, calculate durations, and roll everything into a clean labor summary for pricing and scheduling.
🎯 Learning Objectives
- Pick appropriate base labor units by task (LF pipe, each fitting/fixture, each penetration).
- Apply productivity multipliers for height, access, congestion, occupied work, and weather.
- Build a composite crew rate (base wage + burden) and understand union/prevailing wage implications.
- Translate manhours into durations and crew plans with realistic calendars and shift rules.
- Produce a Labor Summary that maps directly to your estimate and schedule.
1) Labor Units Library
Define baseline manhours under normal conditions: e.g., 1" Cu press = 0.10–0.15 MH/LF; 4" PVC DWV = 0.18–0.25 MH/LF; WC rough-in = 2.5–3.5 MH/ea. Use your company’s historicals where possible.
2) Productivity Factors
Add multipliers for real-world conditions: height (>10 ft), lifts/scaffolds, tight ceilings, occupied/after-hours, congestion, split-face block or thick concrete cores, and inspections/testing.
3) Composite Crew Rates
Build blended rates from crew mix (Foreman, Journeyman, Apprentice) + burden (FICA, WC, GL, fringes, small tools). Use these rates for cost and scenario testing.
4) Union, Prevailing Wage & OT
Account for wage determinations, fringes, travel/subsistence, shift differentials, and overtime premiums (often 1.5×) plus the productivity drop common with extended OT.
5) Durations & Crew Planning
Convert hours to days: Days = MH ÷ (Crew Size × Hours/Day). Add calendar logic (access, inspections, delivery windows), then align with your bid schedule.
6) Risk & Allowances
Carry targeted allowances for high-risk scopes: core drilling, specialty valves, shutdowns, infection control (healthcare), and startup/commissioning support.
🧮 Quick Calcs
- Adjusted Manhours = (Qty × Base Unit Hrs) × Productivity Factor
- Composite Crew Rate ($/hr) = Σ(Role Rate × Qty × (1 + Burden%)) ÷ Crew Size
- Labor Cost = Adjusted MH × Composite Crew Rate
- Duration (Days) = Adjusted MH ÷ (Crew Size × Hours/Day)
- OT Impact ≈ (OT Hours × 1.5 × Rate) and add 5–15% MH growth if extended OT reduces productivity
📊 Sample Labor Summary (Excerpt)
| Area | Task | Qty | Unit Hrs | Factor | Adj MH | Crew Rate | Labor $ |
|---|---|---|---|---|---|---|---|
| L1 Core | 4" PVC DWV Main (LF) | 160 | 0.22 | 1.10 | 38.7 | $78.50 | $3,039 |
| Restrooms A/B | 1" Cu Branch (LF) | 120 | 0.12 | 1.20 | 17.3 | $78.50 | $1,360 |
| Roof | Roof Drains (EA) | 3 | 2.00 | 1.15 | 6.9 | $78.50 | $542 |
Notes: Crew Rate shown as blended (Foreman/Journeyman/Apprentice) with burden.
📂 Module 5 Downloads & Templates
Copy from the blocks below and save as CSV/TXT. Import into your estimating sheet or software.
📚 Labor Unit Library (CSV)
Task,Unit,Base Unit Hrs,Notes PVC DWV 4" (straight),LF,0.22,Normal height/clear access PVC Wye + 1/8 Bend 4",EA,0.45,Branch tie-ins Copper 1" Press (straight),LF,0.12,Includes couplings per 20 LF Ball Valve 1",EA,0.40,Press Core Drill 4",EA,0.75,Concrete ≤ 6" Roof Drain Set,EA,2.00,Includes flashing/tie-in Hanger per LF (typical),LF,0.05,Rod/strap/channel average
📈 Productivity Factors Matrix (CSV)
Condition,Factor,Notes Height > 10 ft,1.20,Lifts/ladders Tight Ceiling/Above Grid,1.15,Coordination delays Occupied/After-Hours,1.10,Noise & access limits Heavy Congestion,1.25,Multi-trade overlap Shaft/Riser Work,1.20,Elevations & safety Extended OT Week,1.05-1.15,Fatigue/efficiency loss
👥 Composite Crew Builder (CSV)
Role,Qty,Base Rate $/hr,Burden %,Eff Rate $/hr Foreman,1,50.00,38%,69.00 Journeyman,1,44.00,38%,60.72 Apprentice,1,28.00,38%,38.64 Crew Size,3,,, Composite Rate $/hr,,,56.45
Composite Rate = (Σ Eff Rate × Qty) ÷ Crew Size
🧾 Labor Summary Sheet (CSV)
Area,System,Task,Qty,Unit,Base Hrs/Unit,Factor,Adj MH,Crew Rate,Cost L1 Core,DWV,4" PVC Main,160,LF,0.22,1.10,38.72,56.45, Restrooms,Water,1" Cu Branch,120,LF,0.12,1.20,17.28,56.45, Roof,Storm,Roof Drain Set,3,EA,2.00,1.15,6.90,56.45,
⏱️ OT & Shift Rules (CSV)
Rule,Premium,Add'l Factor,Notes OT (over 8/day),1.50x,+0.05-0.10,Efficiency hit 2nd Shift Diff,$2.00/hr,0,Add to base rates Weekend Work,1.50x-2.00x,+0.05,Access advantages offset?
🗓️ Weekly Crew Plan (CSV)
Week,Area,Task,Target MH,Crew Size,Hours/Day,Expected Days,Notes Wk 1,L1 Core,4" DWV Main,40,3,8,1.7,Scaffold share with Elec Wk 1,Restrooms,CW/HW Branch,18,3,8,0.8,Above grid Wk 2,Roof,Roof Drains,7,3,8,0.3,Weather watch
📝 Labor Clarifications (Copy/Paste)
• Labor units assume normal access ≤10' AFF unless noted. • Overtime not included unless specifically requested. • Shutdowns and after-hours work carried as allowances where indicated. • Testing/inspections are included per spec; re-tests by others unless caused by our work. • Commissioning support includes (X) hours; additional by change order.
💡 Pro Tips
- Start with “greenfield” units then layer factors—don’t guess a lump sum add.
- Separate hanger/insulation labor from pipe labor for clearer buyout and tracking.
- Document assumptions (access, shifts, shutdown windows) in clarifications.
- Use durations to validate your manpower against the project schedule early.
🧪 Practice Exercise (45–60 min)
- Populate the Labor Unit Library with your company’s typical units.
- Apply the Productivity Matrix to Module 3 quantities for Level 1.
- Build a 3-person composite crew in the Crew Builder and compute the blended rate.
- Complete the Labor Summary Sheet and total Labor $.
- Create a Weekly Crew Plan showing expected durations and notes.
👩🏫 Teacher Notes (Facilitation Guide)
- Demo (10 min): Pick two tasks; show unit selection and factor stacking.
- Workshop (20–25 min): Teams build a composite crew and cost three lines.
- Apply (10–15 min): Convert hours to durations; compare two crew mixes.
- Debrief (5 min): Discuss top labor misses and how to prevent them.