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💼 Afrexai Construction Estimator

afrexai-construction-estimator

住宅、商業施設、インフラなどあらゆる建設プロジェクトにおいて

⏱ 議事録 30分 → 3分

📺 まず動画で見る(YouTube)

▶ 【自動化】AIガチ勢の最新活用術6選がこれ1本で丸分かり!【ClaudeCode・AIエージェント・AI経営・Skills・MCP】 ↗

※ jpskill.com 編集部が参考用に選んだ動画です。動画の内容と Skill の挙動は厳密には一致しないことがあります。

📜 元の英語説明(参考)

Complete construction estimating and cost management system. Use when preparing project estimates, bid proposals, cost breakdowns, value engineering, change order management, or construction budget tracking. Covers residential, commercial, and infrastructure projects. Trigger on 'estimate', 'construction cost', 'bid', 'takeoff', 'cost breakdown', 'change order', 'value engineering', 'construction budget', 'unit pricing', 'RSMeans'.

🇯🇵 日本人クリエイター向け解説

一言でいうと

住宅、商業施設、インフラなどあらゆる建設プロジェクトにおいて

※ jpskill.com 編集部が日本のビジネス現場向けに補足した解説です。Skill本体の挙動とは独立した参考情報です。

⚡ おすすめ: コマンド1行でインストール(60秒)

下記のコマンドをコピーしてターミナル(Mac/Linux)または PowerShell(Windows)に貼り付けてください。 ダウンロード → 解凍 → 配置まで全自動。

🍎 Mac / 🐧 Linux
mkdir -p ~/.claude/skills && cd ~/.claude/skills && curl -L -o afrexai-construction-estimator.zip https://jpskill.com/download/4288.zip && unzip -o afrexai-construction-estimator.zip && rm afrexai-construction-estimator.zip
🪟 Windows (PowerShell)
$d = "$env:USERPROFILE\.claude\skills"; ni -Force -ItemType Directory $d | Out-Null; iwr https://jpskill.com/download/4288.zip -OutFile "$d\afrexai-construction-estimator.zip"; Expand-Archive "$d\afrexai-construction-estimator.zip" -DestinationPath $d -Force; ri "$d\afrexai-construction-estimator.zip"

完了後、Claude Code を再起動 → 普通に「動画プロンプト作って」のように話しかけるだけで自動発動します。

💾 手動でダウンロードしたい(コマンドが難しい人向け)
  1. 1. 下の青いボタンを押して afrexai-construction-estimator.zip をダウンロード
  2. 2. ZIPファイルをダブルクリックで解凍 → afrexai-construction-estimator フォルダができる
  3. 3. そのフォルダを C:\Users\あなたの名前\.claude\skills\(Win)または ~/.claude/skills/(Mac)へ移動
  4. 4. Claude Code を再起動

⚠️ ダウンロード・利用は自己責任でお願いします。当サイトは内容・動作・安全性について責任を負いません。

🎯 このSkillでできること

下記の説明文を読むと、このSkillがあなたに何をしてくれるかが分かります。Claudeにこの分野の依頼をすると、自動で発動します。

📦 インストール方法 (3ステップ)

  1. 1. 上の「ダウンロード」ボタンを押して .skill ファイルを取得
  2. 2. ファイル名の拡張子を .skill から .zip に変えて展開(macは自動展開可)
  3. 3. 展開してできたフォルダを、ホームフォルダの .claude/skills/ に置く
    • · macOS / Linux: ~/.claude/skills/
    • · Windows: %USERPROFILE%\.claude\skills\

Claude Code を再起動すれば完了。「このSkillを使って…」と話しかけなくても、関連する依頼で自動的に呼び出されます。

詳しい使い方ガイドを見る →
最終更新
2026-05-17
取得日時
2026-05-17
同梱ファイル
2

💬 こう話しかけるだけ — サンプルプロンプト

  • Afrexai Construction Estimator で、私のビジネスを分析して改善案を3つ提案して
  • Afrexai Construction Estimator を使って、来週の会議用の資料を作って
  • Afrexai Construction Estimator で、現状の課題を整理してアクションプランに落として

これをClaude Code に貼るだけで、このSkillが自動発動します。

📖 Claude が読む原文 SKILL.md(中身を展開)

この本文は AI(Claude)が読むための原文(英語または中国語)です。日本語訳は順次追加中。

Construction Estimator Pro

Complete construction estimating methodology — from quantity takeoff to bid submission. Zero dependencies.


Phase 1: Project Classification & Estimate Type

Estimate Type Decision Matrix

Project Stage Estimate Type Accuracy Basis Use Case
Concept Order of Magnitude -30% to +50% SF/unit costs Go/no-go decisions
Schematic Conceptual/Budget -15% to +30% Assembly costs Budget approval
Design Dev Detailed -10% to +15% Quantity takeoff GMP/bid preparation
Construction Docs Definitive/Bid -5% to +10% Full QTO + subs Lump sum bid
Construction Control Actual costs Committed + forecast Cost management

Project Brief YAML

project:
  name: ""
  number: ""
  type: residential | commercial | industrial | infrastructure | renovation
  delivery: design-bid-build | design-build | CM-at-risk | IPD
  location:
    city: ""
    state: ""
    zip: ""
    location_factor: 1.00  # RSMeans city cost index / national average
  owner: ""
  architect: ""

scope:
  gross_sf: 0
  stories: 0
  site_acres: 0
  description: ""

schedule:
  bid_date: ""
  construction_start: ""
  substantial_completion: ""
  duration_months: 0

estimate:
  type: order-of-magnitude | conceptual | detailed | definitive
  base_date: ""  # Date costs are based on
  escalation_rate: 0.04  # Annual construction cost escalation

assumptions:
  - ""
exclusions:
  - ""
allowances:
  - item: ""
    amount: 0

Project Type Quick Reference

Type Key Considerations Typical $/SF Range (2024-2026)
Single Family Residential Foundation type, finishes grade, energy code $150-$400/SF
Multi-Family Unit mix, parking ratio, amenities $200-$450/SF
Office (Class A) Curtain wall, MEP density, TI allowance $250-$550/SF
Retail Shell vs TI, storefront, grease traps $150-$350/SF
Healthcare/Hospital Life safety, med gas, shielding $400-$900/SF
K-12 Education Prevailing wage, hazmat, phasing $300-$600/SF
Warehouse/Distribution Clear height, slab flatness, dock count $80-$180/SF
Hotel Star rating drives finish, FF&E budget $200-$500/SF
Infrastructure (road/mile) Soil conditions, utilities, traffic control $2M-$10M/mile

Phase 2: Quantity Takeoff (QTO)

CSI MasterFormat Division Structure

Use CSI MasterFormat 2018 for ALL estimates. Every line item maps to a division.

Division Name Typical % of Total
01 General Requirements 8-12%
02 Existing Conditions 1-5%
03 Concrete 8-15%
04 Masonry 2-6%
05 Metals (Structural Steel) 8-15%
06 Wood, Plastics, Composites 3-8%
07 Thermal & Moisture Protection 4-8%
08 Openings (Doors/Windows) 3-7%
09 Finishes 8-15%
10 Specialties 1-3%
11 Equipment 1-5%
12 Furnishings 1-5%
13 Special Construction 0-3%
14 Conveying Equipment (Elevators) 1-4%
21 Fire Suppression 2-4%
22 Plumbing 4-8%
23 HVAC 8-15%
26 Electrical 8-15%
27 Communications 1-3%
28 Electronic Safety & Security 1-3%
31 Earthwork 3-8%
32 Exterior Improvements 2-6%
33 Utilities 2-5%

QTO Best Practices

  1. Measure twice, price once — QTO errors cascade through the entire estimate
  2. Use consistent units — SF for areas, LF for linear, CY for volume, EA for items
  3. Add waste factors by material:
    • Concrete: 5-8%
    • Masonry: 3-5%
    • Drywall: 10-12%
    • Roofing: 8-10%
    • Flooring (tile): 10-15%
    • Lumber: 8-10%
    • Rebar: 5-7%
    • Paint: 10-15%
  4. Document measurement methodology — so anyone can verify
  5. Cross-check totals — SF of drywall ≈ 2.5-3x floor area (both sides of walls + ceilings)

QTO Line Item Template

line_item:
  division: "03"
  spec_section: "03 30 00"
  description: "Cast-in-Place Concrete - Elevated Slabs"
  quantity: 450
  unit: CY
  unit_cost:
    labor: 85.00
    material: 165.00
    equipment: 25.00
    subcontractor: 0.00
  total_unit_cost: 275.00
  extended_cost: 123750.00
  waste_factor: 0.07
  adjusted_quantity: 481.5
  notes: "4500 PSI, #5 rebar @ 12\" OC EW, 6\" slab"
  source: "Sub quote - ABC Concrete (02/15/2026)"
  confidence: high | medium | low

Quantity Verification Cross-Checks

Check Formula Flag If
Concrete per SF Total CY ÷ Building SF >0.15 CY/SF (unless heavy structure)
Steel per SF Total tons ÷ Building SF >15 PSF (unless high-rise)
Drywall SF Total drywall SF ÷ Floor SF <2.0 or >4.0 ratio
Electrical per SF Electrical $ ÷ Building SF >$35/SF (standard office)
Plumbing fixtures Count vs occupancy Missing fixtures for code compliance
Parking spaces Per local code requirements Below minimum ratio

Phase 3: Pricing & Cost Assembly

Unit Cost Development

Cost source hierarchy (most reliable first):

  1. Subcontractor quotes (3 minimum per trade) — best for bid estimates
  2. Historical project data — adjusted for location, time, scope
  3. RSMeans/Gordian data — industry standard reference
  4. Vendor quotes — for specific materials/equipment
  5. Published cost guides — Marshall & Swift, Craftsman

Labor Cost Build-Up

labor_rate_build_up:
  trade: "Carpenter"
  base_wage: 42.50
  fringe_benefits: 18.75   # Health, pension, vacation, training
  payroll_taxes: 8.90      # FICA, FUTA, SUTA, workers comp
  total_burden: 27.65
  burdened_rate: 70.15

  productivity_factors:
    weather: 1.00           # 1.0 = normal, 1.15 = winter
    overtime: 1.00          # 1.0 = straight time, 1.5 = OT
    height: 1.00            # 1.0 = ground, 1.10 = >30ft
    congestion: 1.00        # 1.0 = open, 1.15 = tight
    shift: 1.00             # 1.0 = day, 1.10 = swing, 1.15 = night
  adjusted_rate: 70.15

Subcontractor Quote Evaluation

Score each sub quote (use minimum 3 per trade):

Factor Weight 1-5 Score
Price competitiveness 30%
Scope completeness (covers all spec sections?) 25%
Qualifications/exclusions (red flags?) 20%
Past performance/reputation 15%
Bond capacity/insurance 10%
Weighted Total 100%

Red flags in sub quotes:

  • "As needed" or "TBD" line items (scope gap)
  • Short validity period (<30 days)
  • Unusual exclusions (e.g., electrician excluding wire)
  • No reference to spec sections
  • Price significantly below others (they missed something)

Crew Rate Assembly

Crew Daily Cost = Σ(Workers × Daily Rate) + Equipment Daily Cost
Crew Daily Output = Units per 8-hour day (from labor standards)
Unit Cost = Crew Daily Cost ÷ Crew Daily Output

Example — Concrete Placement Crew:

  • 1 Foreman @ $75/hr × 8 = $600
  • 4 Laborers @ $55/hr × 8 = $1,760
  • 1 Vibrator operator @ $60/hr × 8 = $480
  • Concrete pump (daily rental) = $1,200
  • Crew Daily Cost = $4,040
  • Daily output: 50 CY
  • Unit Labor+Equipment Cost = $80.80/CY
  • Material (concrete delivered) = $165/CY
  • Total in-place cost = $245.80/CY

Phase 4: Indirect Costs & Markups

General Conditions (Division 01) Checklist

Item Duration-Based? Typical Range
Project Manager Yes $12K-$18K/month
Superintendent Yes $10K-$16K/month
Project Engineer Yes $8K-$12K/month
Field Office (trailer) Yes $1K-$3K/month
Temporary utilities Yes $2K-$5K/month
Temporary toilets Yes $200-$500/month each
Dumpsters/waste removal Yes $1K-$4K/month
Safety equipment/supplies Yes $500-$2K/month
Small tools & consumables Lump 1-2% of labor
Final cleaning Lump $0.15-$0.50/SF
Permits (building) Lump Varies by jurisdiction
Insurance (Builder's Risk) Lump 0.5-1.5% of cost
Performance/Payment Bond Lump 1-3% of contract
Testing & inspection Lump 0.5-1.5% of cost
As-built documentation Lump $5K-$25K
Commissioning support Lump $10K-$50K

Rule of thumb: General conditions = 8-15% of direct costs (lower for large projects, higher for small/complex).

Markup Stack

markup_calculation:
  direct_costs: 2500000

  general_conditions:
    percentage: 0.10
    amount: 250000

  subtotal_1: 2750000

  overhead:
    percentage: 0.05     # Home office overhead
    amount: 137500

  subtotal_2: 2887500

  profit:
    percentage: 0.05     # Varies by market/risk
    amount: 144375

  subtotal_3: 3031875

  contingency:
    design_contingency: 0.05    # For incomplete drawings
    construction_contingency: 0.03  # For unforeseen conditions
    amount: 242550

  bond:
    percentage: 0.015
    amount: 49118

  escalation:
    rate: 0.04           # Annual
    months_to_midpoint: 8
    amount: 88536

  total_estimate: 3412079
  cost_per_sf: 341.21    # For 10,000 SF building

Contingency Guide

Estimate Type Design Contingency Construction Contingency
Order of Magnitude 15-25% 10-15%
Conceptual 10-15% 5-10%
Detailed 3-8% 3-5%
Definitive/Bid 0-3% 2-3%

Contingency is NOT profit padding. Track and justify every contingency draw.


Phase 5: Bid Preparation & Strategy

Bid/No-Bid Decision Scorecard

Score 1-5 for each (minimum 30 to bid):

Factor Weight Score
Project type experience 3x
Client relationship/history 2x
Current workload capacity 3x
Geographic fit 2x
Profit potential 3x
Competition level (fewer = better) 2x
Risk profile (lower = better) 3x
Schedule feasibility 2x
Bonding capacity available 2x
Weighted Total /110

Bid Day Checklist

48 hours before:

  • [ ] All sub quotes received (minimum 3 per trade)
  • [ ] All material quotes current (check expiration dates)
  • [ ] Addenda reviewed and incorporated (ALL of them)
  • [ ] Scope gaps identified and plugged
  • [ ] Math verified (independent check)

Day of bid:

  • [ ] Final sub quotes plugged in
  • [ ] Markup/profit decision finalized
  • [ ] Alternates priced if required
  • [ ] Unit prices calculated if required
  • [ ] Bid bond secured
  • [ ] Bid form completed correctly (every blank filled)
  • [ ] Acknowledge ALL addenda on bid form
  • [ ] Authorized signature
  • [ ] Delivered before deadline (allow 1+ hour buffer)

Competitive Bid Strategy

Market conditions affect markup:

  • Hot market (lots of work): Markup 8-12% (O&P combined)
  • Normal market: Markup 6-10%
  • Slow market: Markup 3-6%
  • Must-win/strategic: Markup 2-4% (minimum to cover overhead)

Bid spread analysis (track your results):

Bid Spread = (Your Bid - Low Bid) ÷ Low Bid × 100
  • Consistently >10% high → Your costs are inflated or productivity assumptions too conservative
  • Consistently <2% from low → You might be leaving money on the table
  • Target: Within 3-5% of winning bid

Phase 6: Value Engineering (VE)

VE Opportunity Matrix

System VE Opportunity Typical Savings Risk Level
Structural Steel vs concrete frame 5-15% of structure Medium
Foundations Spread vs mat vs piles 10-30% of foundation High (geotech dependent)
Envelope Curtain wall vs storefront 15-30% of facade Low-Medium
Roofing TPO vs modified bitumen 10-20% of roofing Low
Mechanical VAV vs VRF 10-25% of HVAC Medium
Electrical LED fixtures, panel optimization 5-15% of electrical Low
Finishes Material substitutions 10-40% of finishes Low
Site Reduce import/export of soil 10-30% of sitework Medium

VE Proposal Template

ve_item:
  number: VE-001
  description: "Substitute VRF system for conventional VAV"
  division: "23"

  original:
    description: "VAV air handling system with ductwork"
    cost: 850000

  proposed:
    description: "Variable Refrigerant Flow (VRF) with DOAS"
    cost: 680000

  savings: 170000
  savings_pct: 20%

  impact:
    schedule: "Reduces mechanical rough-in by 2 weeks"
    quality: "Better zone control, lower operating cost"
    maintenance: "Higher per-unit cost but less ductwork"
    code_compliance: "Meets ASHRAE 90.1, verify local amendments"

  risk: medium
  recommendation: accept | reject | modify
  requires_redesign: yes | no
  redesign_cost: 15000
  net_savings: 155000

VE Decision Rules

  1. Never VE life safety — fire protection, structural integrity, egress
  2. Calculate lifecycle cost — cheap upfront ≠ cheap over 20 years
  3. Get architect/engineer sign-off before bidding VE alternates
  4. Document everything — VE that isn't documented becomes a scope gap
  5. Owner decides — present options with data, let them choose

Phase 7: Change Order Management

Change Order Pricing Rules

Contractor markup on changes (typical): | Tier | Self-Performed Work | Subcontractor Work | |---|---|---| | Overhead | 10% | 5% | | Profit | 10% | 5% | | Bond | Add actual % | Add actual % |

Time & Material (T&M) documentation requirements:

  • Daily time sheets signed by owner's rep
  • Material invoices with delivery tickets
  • Equipment logs with hours
  • Photos of work in progress

Change Order YAML Template

change_order:
  number: CO-001
  date: ""
  description: ""

  reason:
    type: owner-directed | unforeseen-condition | design-error | code-change | scope-clarification
    rfi_number: ""

  cost_breakdown:
    labor:
      hours: 0
      rate: 0
      total: 0
    material:
      items: []
      total: 0
    equipment:
      items: []
      total: 0
    subcontractor:
      items: []
      total: 0
    direct_cost: 0
    markup: 0.15
    total_cost: 0

  schedule_impact:
    days: 0
    critical_path: yes | no
    explanation: ""

  status: pending | approved | rejected | negotiating

Change Order Negotiation Tips

  1. Price it immediately — delay weakens your position
  2. Submit with backup — labor rates, material quotes, productivity analysis
  3. Separate time from money — negotiate schedule impact independently
  4. Track cumulative impact — 20 small changes = major schedule disruption (even if each is "0 days")
  5. Constructive acceleration — if owner delays approval but expects same completion, document it
  6. Unit price book — agree on unit prices at contract start for common change types

Phase 8: Cost Control During Construction

Earned Value Management (EVM)

Budget at Completion (BAC) = Total budget
Planned Value (PV) = Budgeted cost of work scheduled
Earned Value (EV) = Budgeted cost of work performed
Actual Cost (AC) = Actual cost of work performed

Schedule Performance Index (SPI) = EV / PV
  >1.0 = ahead of schedule
  <1.0 = behind schedule

Cost Performance Index (CPI) = EV / AC
  >1.0 = under budget
  <1.0 = over budget

Estimate at Completion (EAC) = BAC / CPI
Variance at Completion (VAC) = BAC - EAC

Monthly Cost Report Template

cost_report:
  project: ""
  period: ""
  report_date: ""

  summary:
    original_contract: 0
    approved_changes: 0
    pending_changes: 0
    current_budget: 0
    committed_cost: 0      # Subcontracts + POs
    actual_cost_to_date: 0
    forecast_to_complete: 0
    estimate_at_completion: 0
    variance: 0
    contingency_remaining: 0

  schedule:
    percent_complete: 0
    spi: 0
    cpi: 0
    days_ahead_behind: 0

  cash_flow:
    billed_to_date: 0
    collected_to_date: 0
    retention_held: 0

  risk_items:
    - description: ""
      potential_cost: 0
      probability: high | medium | low
      mitigation: ""

Cost Control Red Flags

Signal What It Means Action
CPI < 0.95 in first 25% Systemic cost overrun Root cause analysis NOW
Contingency burn > schedule % Burning contingency too fast Tighten change management
>5 pending COs unsigned Cash flow risk, scope dispute Escalate to PM/owner
Sub invoices > committed Sub performing extra work Verify scope, issue CO or stop work
Retainage release requests early Sub cash flow problems Monitor closely, check lien waivers

Phase 9: Specialty Estimate Types

Renovation/Remodel Estimating

Add these factors to renovation estimates:

  • Selective demolition: Price item-by-item (never lump sum)
  • Hazmat survey: Asbestos ($3-5K), lead paint ($2-4K) — MANDATORY before bid
  • Abatement: 2-5x removal cost vs new construction equivalent
  • Protection of existing: Dust barriers, floor protection, HVAC isolation
  • Working hours: Occupied buildings = nights/weekends = premium labor
  • Discovery allowance: 10-15% for hidden conditions behind walls
  • Temporary facilities: HVAC, power, restrooms during renovation
  • Phasing/sequencing: Adds 15-30% management overhead

Sitework Estimating

Critical factors:

sitework_checklist:
  geotechnical:
    - Soil bearing capacity
    - Water table depth  
    - Rock depth (blasting vs mechanical?)
    - Contamination (Phase I/II ESA results)

  earthwork:
    cut_cy: 0
    fill_cy: 0
    import_export: 0    # Net CY to haul
    haul_distance_miles: 0
    compaction_required: standard | proctor_95 | proctor_98

  utilities:
    water_tap_fee: 0
    sewer_tap_fee: 0
    fire_line: 0
    storm_detention: required | not_required

  paving:
    asphalt_sy: 0
    concrete_sy: 0
    curb_lf: 0
    striping_lf: 0

  landscape:
    sod_sf: 0
    trees_ea: 0
    irrigation: yes | no
    erosion_control: silt_fence | inlet_protection | retention_pond

MEP (Mechanical/Electrical/Plumbing) Quick Checks

System $/SF Benchmark (Commercial Office) Flag If
HVAC $25-$50/SF >$55 or <$20
Plumbing $12-$25/SF >$30 or <$8
Fire Protection $4-$8/SF >$10 or <$3
Electrical (power) $18-$35/SF >$40 or <$12
Low voltage/data $5-$12/SF >$15 or <$3
Total MEP $64-$130/SF >$150 or <$46

Phase 10: Escalation & Location Adjustments

Construction Cost Escalation

Future Cost = Current Cost × (1 + Annual Rate) ^ (Months to Midpoint ÷ 12)

Recent escalation trends (US):

  • 2020-2022: 8-15% annually (pandemic/supply chain)
  • 2023-2024: 4-6% annually (normalizing)
  • 2025-2026 forecast: 3-5% annually
  • Long-term average: 3-4% annually

Always escalate to the MIDPOINT of construction, not the start.

Location Factor Application

Local Cost = National Average Cost × City Cost Index

Sample RSMeans City Cost Indices (100 = national average):

City Index City Index
New York, NY 130-145 Dallas, TX 88-95
San Francisco, CA 125-140 Atlanta, GA 90-97
Boston, MA 115-130 Phoenix, AZ 88-94
Chicago, IL 110-120 Denver, CO 95-105
Seattle, WA 108-118 Nashville, TN 88-95
Washington, DC 100-110 Charlotte, NC 85-92
Miami, FL 92-100 Houston, TX 85-93
Minneapolis, MN 105-112 Rural areas 70-85

Phase 11: Estimate Quality Review

100-Point Estimate Quality Rubric

Dimension Weight Criteria
Scope completeness 20 All spec sections priced, no gaps, exclusions documented
Quantity accuracy 20 QTO verified, cross-checks pass, waste factors applied
Pricing basis 15 3+ sub quotes per trade, current material prices, documented sources
Indirect costs 10 GCs detailed (not lump), schedule-based items tied to duration
Markup appropriateness 10 Market-competitive, risk-adjusted, contingency justified
Documentation 10 Assumptions listed, basis of estimate narrative, organized by division
Adjustments 10 Location factor applied, escalation to midpoint, seasonal factors
Presentation 5 Professional format, clear summary, alternates separated

Grading: 90+ = Bid-ready | 75-89 = Needs refinement | 60-74 = Major gaps | <60 = Redo

Peer Review Checklist

  • [ ] All addenda acknowledged and incorporated?
  • [ ] Spec sections cross-referenced to QTO? (no orphan specs)
  • [ ] Sub quotes match scope of work? (read exclusions!)
  • [ ] General conditions duration matches schedule?
  • [ ] Bond premium calculated on TOTAL including markups?
  • [ ] Sales tax applied correctly? (varies by state, some exempt)
  • [ ] Prevailing wage rates used if required? (Davis-Bacon, state)
  • [ ] Owner-furnished items excluded from pricing?
  • [ ] Alternates priced separately and clearly?
  • [ ] Math checked independently? (not just formula check — spot-check quantities)

Phase 12: Common Mistakes & Edge Cases

10 Estimate-Killing Mistakes

# Mistake Prevention
1 Missing addenda Checklist: log every addendum, initial when incorporated
2 Incomplete sub scope Write scope sheets with inclusions AND exclusions
3 Wrong labor rates Verify union vs open shop, prevailing wage, location
4 No escalation ALWAYS escalate to construction midpoint
5 Lump sum general conditions Detail every line item tied to schedule
6 Ignoring phasing Multi-phase = mobilize/demobilize multiple times
7 Missing temporary work Shoring, dewatering, winter protection, dust control
8 Under-priced site conditions Get geotech report BEFORE estimating foundations
9 Scope gaps between trades Who installs the backing for the TV mount?
10 Not reading the fine print Liquidated damages, retainage, payment terms

Edge Cases

Occupied building renovation:

  • Work hours restriction → labor premium 15-40%
  • Dust/noise control → add $2-5/SF
  • Security/escort requirements → add supervision cost
  • Existing condition discovery → 10-15% allowance minimum

Remote/rural project:

  • Travel/per diem for crews → $150-$250/worker/day
  • Material delivery premium → 5-15% depending on distance
  • Limited sub market → fewer quotes, less competitive pricing
  • Equipment mobilization → long haul costs for cranes, excavators

Fast-track schedule:

  • Overtime premium → plan 20-30% labor cost increase
  • Acceleration costs → additional supervision, equipment
  • Out-of-sequence work → productivity losses 10-25%
  • Premium material delivery → expediting fees

Public/government work:

  • Prevailing wages → 20-40% labor cost increase
  • DBE/MBE/WBE goals → subcontracting requirements, good faith effort
  • Buy American/Buy America → material cost premium 10-30%
  • Bid protest risk → ensure perfect compliance with ITB

Design-Build:

  • Design contingency higher (incomplete docs at pricing)
  • Self-perform vs sub trade-offs
  • Design liability insurance (professional liability)
  • Allowances for owner decisions not yet made

Natural Language Commands

Command Action
"Estimate this project" Run full estimate workflow from Phase 1
"Price [division/trade]" Develop unit costs for specific trade
"Check my quantities" Run QTO verification cross-checks
"Value engineer [system]" Generate VE alternatives with savings
"Write change order for [scope]" Generate CO with pricing and backup
"Compare sub quotes for [trade]" Score and compare subcontractor bids
"Monthly cost report" Generate EVM-based cost report
"Bid/no-bid analysis for [project]" Run decision scorecard
"Location adjust to [city]" Apply RSMeans location factor
"Escalate costs to [date]" Calculate escalation to future midpoint
"Review my estimate" Run 100-point quality rubric
"Generate bid summary" Format estimate for bid submission

同梱ファイル

※ ZIPに含まれるファイル一覧。`SKILL.md` 本体に加え、参考資料・サンプル・スクリプトが入っている場合があります。