ROOFING
How to Estimate a Roof Replacement Job
Step-by-step method for contractors to estimate a roof replacement: measurements, waste, tear-off and labor.
Roof replacement estimates fail when contractors undercount waste, skip the pitch factor or forget tear-off and disposal. Here is the process that keeps bids accurate.
THE SHORT ANSWER
How do you estimate a roof replacement?
Measure the true footprint, apply a pitch factor (x1.15 medium, x1.35 steep) and 5-15% waste, then price material per sq ft, labor, tear-off layers and disposal. A 2,000 sq ft asphalt roof runs $10,000-$16,000 installed.
Measure the actual footprint
Walk the roof and measure the footprint in sq ft — do not trust the old paperwork. For a two-story home, include the overhangs and the porch or garage rooflines.
- Measure every plane separately
- Add the overhang
- Note hips, valleys and dormers
- Re-measure at the ridge line
Apply pitch and waste factors
A medium pitch (6/12-8/12) adds 15% to labor because crews work slower; a steep pitch (10/12+) adds 35%. Cut waste runs 5-15% depending on how complex the roof is.
Price material, tear-off and disposal
Shingles run $3.50-$5.50/sq ft, metal $7-$12, tile $8-$15. Each layer of old shingles adds tear-off labor, and a dumpster for the debris costs real money. Use the Roof Replacement Cost Calculator to build the line items.
Add labor and check the total
Labor averages $1.50-$3/sq ft depending on crew and region. Your final number should be within 10% of the calculator output before you add your markup.