Roof measurement, waste & material handoff
Separate the roof you measured from the covering you will order, and keep edge work visible in the supplier list.
Use the horizontal footprint with pitch, or use an already measured sloped area. Applying a pitch factor to an area that is already sloped counts the slope twice.
Footprint or roof surface?
Mark which kind of area your plan gives. Footprint length and width include overhangs; pitch describes the same plane. Add each distinct pitch as a separate section. Use plans or a professional measurement rather than accessing the roof.
Waste belongs after area
Sum the sloped sections, then apply the allowance you choose for this covering and layout. Keep measured squares and ordering squares separate. The allowance is not a design for hips, valleys or dormers.
Make the accessory list measurable
Write down eave, rake, ridge and hip lengths. Add underlayment roll coverage and usable edge/cap coverage after overlap. Ask separately about starters, flashing, sheathing, penetrations and ventilation.
Hand off the same scope
Take the measured area, allowance, package label and edge lengths to each supplier or roofer. Confirm whether their stated area already includes cuts before comparing quantities.
See the measurement become an order
Example: a 30 × 20 ft horizontal footprint at 6:12 pitch, with a chosen 10% allowance. The editable bundle coverage is 100/3 sq ft.
This example gives 23 shingle bundles.
- Section 1: 600 sq ft × 1.118 = 670.82 sq ft
- 670.82 × (1 + 10/100) ÷ 33.3333 = 22.14 bundles before rounding.