Roofing Estimating Guide
How to Bid a Roofing Job
Accurate roofing bids require understanding pitch factors, material costs, labor rates, and complexity adjustments. This guide walks through the complete process of calculating profitable roofing estimates.
Quick Answer
Calculate roof squares (area ÷ 100), apply pitch factor, price at $350-$700/square for shingles installed. Add tear-off costs ($100-$175/square), overhead (30-45%), and profit (15-25%). A 25-square roof at $500/square = $12,500 before adjustments.
Step 1: Measure the Roof
Accurate measurements are the foundation of accurate bids. You have several options:
- Ground measurements + pitch factor: Measure footprint from ground, multiply by pitch factor
- Direct measurement: Walk the roof with a measuring wheel or tape
- Aerial measurement services: EagleView, GAF QuickMeasure, or satellite tools provide accurate reports
Pitch Multipliers
| Roof Pitch | Pitch Factor | 2,000 sq ft Footprint Becomes |
|---|---|---|
| Flat to 3/12 | 1.031 | 2,062 sq ft |
| 4/12 | 1.054 | 2,108 sq ft |
| 5/12 | 1.083 | 2,166 sq ft |
| 6/12 | 1.118 | 2,236 sq ft |
| 7/12 | 1.158 | 2,316 sq ft |
| 8/12 | 1.202 | 2,404 sq ft |
| 9/12 | 1.250 | 2,500 sq ft |
| 10/12 | 1.302 | 2,604 sq ft |
| 12/12 | 1.414 | 2,828 sq ft |
Roofing Squares Formula
Squares = (Footprint sq ft × Pitch Factor) ÷ 100
Step 2: Calculate Material Costs
List all materials needed for the job:
| Material | Typical Cost | Per |
|---|---|---|
| 3-tab shingles | $90-$110 | Square |
| Architectural shingles | $120-$180 | Square |
| Premium/designer shingles | $200-$400 | Square |
| Synthetic underlayment | $50-$80 | Square |
| Ice & water shield | $80-$120 | Roll (2 squares) |
| Drip edge | $1.50-$3.00 | Linear foot |
| Ridge cap | $40-$60 | Bundle (covers 25-35 LF) |
| Starter strip | $25-$40 | Bundle |
| Roofing nails | $50-$70 | Box (enough for ~10 squares) |
| Pipe boots/flashing | $15-$40 | Each |
Add Waste Factor
Add 10-15% waste for standard roofs, 15-20% for complex roofs with many hips, valleys, and cuts. Material waste is inevitable and must be included in your bid.
Step 3: Calculate Labor Costs
Labor depends on crew size, production rate, and complexity:
| Task | Production Rate | Notes |
|---|---|---|
| Tear-off (1 layer) | 15-25 squares/day (4-person crew) | Slower for multiple layers |
| Install underlayment | 30-50 squares/day | Depends on type |
| Install shingles | 15-25 squares/day (4-person crew) | Slower for complex roofs |
| Flashing/details | Varies | Add time for chimneys, skylights |
Example: 25-square roof, 6/12 pitch, 1 layer tear-off
- Tear-off: 1.25 days × 4 workers × 8 hours × $35/hour = $1,400
- Install: 1.5 days × 4 workers × 8 hours × $35/hour = $1,680
- Details/cleanup: 0.5 days × 2 workers × 8 hours × $35/hour = $280
- Total labor: $3,360
Step 4: Add Overhead and Profit
Use the standard contractor pricing formula:
Roofing Bid Formula
Bid = (Materials + Labor + Subs) × (1 + Overhead) ÷ (1 – Profit Margin)
Continuing the example:
- Materials: $4,200 (shingles, underlayment, accessories, waste)
- Labor: $3,360
- Dumpster: $450
- Permits: $150
- Direct costs: $8,160
- With 35% overhead: $8,160 × 1.35 = $11,016
- For 20% profit: $11,016 ÷ 0.80 = $13,770 bid price
That works out to about $551 per square installed, including tear-off.
Step 5: Adjust for Complexity
Add premiums for challenging conditions:
| Factor | Price Adjustment |
|---|---|
| Steep pitch (8/12+) | +15-30% |
| Multiple layers tear-off | +$75-$125/square per layer |
| Wood rot repair | $50-$150/sheet + labor |
| Limited access | +10-20% |
| Skylights (existing) | +$150-$300 each |
| Chimney flashing | +$300-$600 |
| Story height (3+) | +15-25% |
| Cut-up roof (many hips/valleys) | +20-35% |
Don’t Forget Disposal
Dumpster rental and dump fees add $400-$600 per 20-yard container. One container typically handles 20-25 squares of tear-off. Heavy shake or tile roofs need larger containers and cost more to dispose.
Roofing Bid Checklist
Include these items in every roofing estimate:
- Tear-off scope (number of layers, material type)
- Disposal method and cost
- Underlayment type and coverage
- Shingle brand, product line, and color
- Warranty information (manufacturer and workmanship)
- Flashing replacement/repair scope
- Drip edge, vents, pipe boots
- Ice and water shield locations
- Timeline and crew size
- Payment terms and schedule
- Exclusions: structural repairs, gutters, interior damage, permits (if not included)
Free Tool: Use our Roof Replacement Cost Calculator to get instant estimates for your area.
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