The roof quote covers the shingles. Then a line near the bottom says rotten wood extra. That line deserves more attention than its font size suggests.
Ask what can and cannot be known beforehand
An initial inspection may reveal warning signs without exposing every part of the roof deck. IKO's sheathing guide explains the role of the substrate and why damaged areas may need replacement. The actual extent can remain uncertain until the covering is removed.
Ask the roofer what evidence supports the current allowance and what discovery process they will use. Neither a zero allowance nor an enormous contingency is automatically the right answer.
Make the price understandable
Request the charging basis for replacement, including material specification, labour, disposal, and any minimum charges. Ask how supporting-framing repairs would be handled separately if discovered. Replacing sheathing and repairing structure are not identical scopes.
Agree how decisions happen on the day
- Who receives photographs and the proposed additional scope?
- How quickly must approval be available while the roof is exposed?
- What temporary weather protection is included if work pauses?
- How will the final quantity and repair locations be recorded?
Keep someone reachable, but do not let urgency substitute for evidence. A good contractor can explain the finding and the next step clearly.
The practical next step is to choose transparency over an artificially tidy initial number. The best allowance is not the one that promises no surprises. It is the one that makes a real discovery manageable.