Roofing bid cost calculator

Roofing bid math — squares first, then everything else

A roofer's bid is built on squares, not square feet. One square = 100 sqft of roof surface. Pitch and complexity matter, but the squares number anchors every other line item: shingles, underlayment, dump fees, labor.

The four cost buckets

1. Materials — shingles, underlayment, ice & water shield, drip edge, vents, ridge cap. Architectural 30-year shingles run $90-130/sq, premium / impact-rated $150-220/sq.
2. Labor — install + tear-off. Most reroofs include tearing off the old layer (code in most jurisdictions if you're already on layer two). Combined labor is $150-300/sq depending on pitch and access.
3. Dump fees + permit — a 20-yard dumpster handles 20-25 squares of tear-off. Permit is jurisdiction-dependent, $150-500.
4. Overhead + profit — 20-25% markup on the rest covers warranty, insurance, vehicles, and the contractor's actual profit. If a bid doesn't include this, the contractor will eat into job quality to survive.

Why bids vary 30%

Steep pitch (>8/12) adds harness time. Multiple layers of existing roof double tear-off labor. Skylight flashing, satellite mounts, and chimney crickets all add line items. The squares × rate formula gives the floor — adjust upward for complexity.