Start with the correct fireplace drawing
Find the manufacturer's installation instructions for the existing model and look for outside-air components or options. The mere presence of an optional kit in a manual does not establish that this house has it. A drawing showing the expected route can help the inspector identify the accessible portions without tearing into finished walls. CSIA's factory-built fireplace checklist addresses installed components and conditions of access.
Record what appeared when finishes changed
Give the provider a photograph of the wall from a safe location and an older view if a planter, deck or cladding was added later. Identify the room on the opposite side. Do not probe the duct, move a damper or run appliances to identify it by sound. If a grille was already removed during demolition, save any markings and tell the project team to leave the opening identifiable.
Obtain a specific instruction for the finish crew
A useful handoff identifies the grille's function, whether its path was confirmed, and which components or clearances will need to remain available after the work. If a source of combustion air is missing or blocked, the fireplace should remain unused until its actual design and safe condition are resolved. Preserve that decision in the house record for the next exterior project.