Roofing business guide
Roofing job costing guide
For roofing work, a reliable process should compare estimated and actual labor, material and overhead. Record measured area, pitch, layer count, material and weather, and itemize each roof square, labor hour, material and disposal that affects the price.
Cost a roofing job from measured roof surface, material specification, tear-off, access, labor, equipment and disposal. Convert roof area into the supplier’s ordering unit and state any allowance; plan-area measurements alone can understate a pitched roof’s surface.
Use roof surface area and the correct unit
A roofing square is 100 square feet of roof surface. A measured surface of 2,000 square feet equals 20 squares before allowance. An illustrative 10% material allowance produces 22 squares; it is not a universal requirement for every layout or product.
For a simple uniform pitched plane, a pitch of 6 inches rise per 12 inches run gives a factor of √(1 + (6 ÷ 12)²), approximately 1.118. Complex geometry, overhangs, valleys and dormers require separate measurement. A calculator does not replace an appropriate site assessment.
Build the complete cost schedule
Use actual supplier quantities and prices for the specified roofing system. Confirm included layers and accessories, then add job-specific labor and equipment.
| Cost category | What to record |
|---|---|
| Roofing materials | Measured surface, product unit and allowance |
| Underlayment, flashing and accessories | Specified items and quantities |
| Tear-off and disposal | Existing layers and removal scope |
| Labor | Crew person-hours by task |
| Access and equipment | Hire, setup and handling |
| Overhead and profit | Explicit allocation and price method |
Describe uncertain substrate work
Where the condition of concealed decking cannot be known before removal, explain how additional repairs will be measured, priced and approved. Distinguish these provisional items from the known replacement scope. State weather, access and schedule assumptions.
Keep material delivery records, removed quantities, actual crew time and approved changes with the job. Show deposits, stage payments and the remaining balance separately when invoicing. Review estimate-to-actual differences before using the same productivity assumptions on another roof.
Frequently asked questions
How many roofing squares are in 2,000 square feet?
Twenty roofing squares, because one roofing square equals 100 square feet. Add any stated allowance separately and confirm the supplier’s ordering units.
Can I use building floor area as roof area?
Floor or plan area is not necessarily roof surface area. Pitch, overhangs and roof geometry affect the measured surface and material quantity.