How to Write a Supplement Request Letter That Gets the Carrier to Reopen Your Estimate
What Is a Supplement Request?
A supplement request is a formal demand that an insurance carrier reopen a closed or partially paid claim to account for additional damage discovered after the initial estimate. Most property insurance policies allow supplements when additional damage is discovered, even after a partial payment has been made.
When to File a Supplement Request
- Additional damage is discovered during the repair process (rotted decking under shingles, water intrusion behind walls, hidden mold)
- The carrier's initial estimate omitted line items required by code or manufacturer specifications
- Material prices have increased significantly since the carrier's estimate was written
- Mitigation costs were denied or underpaid and IICRC documentation supports the full scope
- Matching materials are required to restore the property to pre-loss condition
The Anatomy of a Supplement Request Letter That Gets Paid
1. The header. Reference the original claim number, date of loss, date of original estimate, and the carrier's adjuster name.
2. The legal basis. Most policies contain language allowing supplements for damage not reasonably discoverable at the time of the initial inspection. Quote this language directly and cite the applicable state prompt payment statute.
3. The itemized supplement scope. For each new damage item: description, location, cause, why it was not visible at the initial inspection, and estimated repair cost. Reference Xactimate line items by name to speak the carrier's language.
4. IICRC citations for mitigation supplements. Cite ANSI/IICRC S500 for water damage, S520 for mold, S700 for fire and smoke. Include equipment logs and moisture readings.
5. The revised total table. A clear three-line table: Original Estimate, Supplement Amount, Revised Total.
6. The deadline and escalation language. Demand a written response within 15 business days. State that failure to respond will result in escalation to the state insurance commissioner, appraisal, or litigation.
Xactimate Line Items: Speak the Carrier's Language
| Xactimate Code | Description | Common Supplement Scenario |
|---|---|---|
| RFG COMP | Composition Shingle R&R | Additional squares discovered during tear-off |
| RFG DECK | Roof Decking R&R | Rotted or damaged decking not visible before tear-off |
| WTR EXTR | Water Extraction | Additional extraction required after initial mitigation |
| DRY WALL | Drywall R&R | Hidden water damage behind walls discovered during repairs |
| MOLD REM | Mold Remediation | Mold discovered during water damage repairs |
| PAINT WALL | Paint Wall | Matching paint required for undamaged adjacent walls |
Generate a Supplement Request Letter in 90 Seconds
PublicAdjusterTool generates a complete, carrier-ready Supplement Request Letter in under 90 seconds. Describe the original claim and the newly discovered damage — the tool produces a fully formatted letter with Xactimate line item references, IICRC standard citations, a revised total table, and state-specific prompt payment statute language.
See also: How IICRC S500 Documentation Wins Water Damage Disputes, How to Write a Negotiation Response Letter, and IICRC Mitigation Review: How Public Adjusters Use Standards to Win Disputes. View pricing.
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