Why are roofing quotes so different for the same house?

One-Minute Answer

Roof quotes are different because the scope is different, even when the shingle name matches. One bid includes tear-off, flashing at walls and chimneys, ventilation corrections, and clear cleanup. Another price new shingles and leaves the rest as “if needed.” [Owens Corning]

To compare quotes, ignore the total first and compare three things: the written scope, photo proof of what is wrong, and the change order process. A change order should be written and should list scope, cost, and schedule impact before extra work happens. [Procore]

Next step:
Have every contractor fill out the same one-page checklist of inclusions and exclusions. If they will not, move on.

If you are choosing between two quotes, we can give you a range for each scope path so the decision is clear.

1) What people usually get wrong:

• They compare only the bottom-line price and ignore what was excluded.
• They assume “same shingles” means “same roof,” even though transitions and ventilation drive a lot of performance.
• They accept “repair as needed” with no unit pricing, photo proof, or approval step.

2) The decision guide:

A) If you want the lowest number (Confirm what is not included. Then decide if you are OK with change orders later for missing items.)

B) If you want the lowest risk of leaks and surprises (Choose the bid with the clearest written scope and the strongest photo documentation. The goal is fewer unknowns.)

C) If you want the roof to look better from the street (Confirm what is not included. Then decide if you are OK with change orders later for missing items.)

3) What can go sideways:

• Decking charges that feel like a shock
  • Cause: the quote did not define how decking replacement is measured and approved.
    Prevent: require written unit pricing or a written approval process with photos.

• Leaks at walls, chimneys, and valleys
  • Cause: ventilation is easy to skip and hard to notice from the driveway.
    Prevent: the scope should name each major transition and what gets replaced.

• Ventilation left unchanged
  • Cause: the quote did not define how decking replacement is measured and approved.
    Prevent: ask for the intake and exhaust plan in writing and how it will be verified.

• Cleanup that is not actually complete
  • Cause: disposal and nail pickup were not planned.
    Prevent: require daily cleanup and a magnetic sweep of the perimeter.

4) Proof you should ask for (even if you never hire us).

• A written scope that lists tear-off, underlayment, flashing, ventilation, and cleanup.
• Photos of the actual roof conditions, not only a satellite measurement.
• A written change order process for decking and hidden conditions, with an approval step.
• Milestone photos of the deck, underlayment, and flashing before the shingles cover it.
• A jobsite protection checklist plus daily cleanup, magnetic sweep, and perimeter checks.

5) Related resources.

• Residential Roofing