09/01/2026
What a supplement actually is — because the word sounds like a fight, and it isn't.
A supplement is a documented request to add missing items, or correct underpriced ones, on an insurance estimate after the claim is approved. Carriers process them every single day. It's routine.
How it works:
1. The contractor documents the gap. They compare the insurance estimate to what the job actually requires and back up each missing item with photos, measurements, and where applicable, local building code citations.
2. It's submitted to the carrier. The contractor sends it as the repair vendor, the same way any tradesperson itemizes the true cost of their own work.
3. The carrier reviews. A desk adjuster may approve from the documentation, ask questions, or send someone to re-inspect. Days to several weeks.
4. The estimate is revised, and the carrier issues additional payment.
Some supplements go in before work starts (visible items like missing drip edge). Others come mid-job, when tear-off reveals rotten decking or a second shingle layer.
Your job as the homeowner is small: authorize it, forward paperwork promptly, and follow up if it stalls. A polite call from the customer often moves things faster than another call from the contractor.
Why insurance estimates come in low, which line items adjusters commonly miss, and how the supplement process adds missing items to an Illinois roof or siding claim.