What the service should establish
Ask for photographs and a description of the deposits, the proposed removal method and its compatibility with the liner. Inspection levels and informal descriptions of creosote stages are different concepts; clarify which one the contractor means.
Where the scope stops
A chemical cleaning product is not a replacement for professional inspection and mechanical cleaning. Never attempt to burn deposits out. The contractor should explain removal limitations and what remains unresolved after the work.
What changes the work and the quote?
Describe the appliance, fuel, number of flues and last known service before requesting an estimate. Roof height, access restrictions, concealed areas and earlier alterations can affect what can be assessed or completed. Ask the contractor to distinguish a known requirement from an allowance that may change after examination.
Request the investigation or service fee separately from optional repairs. A revised scope should identify the newly documented condition, the proposed response and the change in price before additional work is authorized. Photographs are most useful when they identify the component and location, not just a close-up without context.
Keep a record that the next professional can use
Ask for the date, appliance identification, completed work, access limitations and outstanding recommendations. Keep product information and any written warranty with the report. A completed service invoice does not by itself establish that every part of the system was examined or that every concern was resolved.
Use your Chimney Passport to organize the handover and the Quote Comparison Lab to flag exclusions before choosing a company.
Background and safety references
For inspection and maintenance background, consult CSIA homeowner resources. Product-specific work follows the applicable manufacturer instructions and local requirements. Our official resources page separates government safety advice from industry education.