What the scenario represents
The geometry estimates roof surface from footprint, pitch and a 5% overhang assumption, then divides by 100 for squares. Dormers, additions and complex intersections need actual measurements. The dollar bands are chosen budgeting coefficients, not observed market averages or a confidence interval.
Read the output line by line
For shingles, the model adds assumed tear-off, materials, underlayment, labor, flashing and permit amounts. Pitch and story choices scale the labor assumption. Metal uses a different assumed per-square budget. Decking is the quantity you enter multiplied by a modeled per-sheet allowance; its actual condition is unknown before inspection.
A lower modeled total does not establish that an overlay is permitted, safe or appropriate. Check manufacturer instructions, local requirements and the actual roof condition with the responsible contractor.
Turn the scenario into a quote comparison
Request the measured area, material specification, included tear-off layers, flashing scope, disposal, permit responsibility and written concealed-damage unit prices. Compare the same scope, rather than comparing a total against an unsupported national range.
Use our scope and payment worksheet alongside the FTC contractor guidance. For a purchase paid over several years, the ownership budget worksheet keeps the holding period and recurring costs consistent.