afrexai-construction-estimator

# 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 ```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 ```yaml 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 ```yaml 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 ```yaml 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 |