The difference between a paid supplement and one that gets ignored often comes down to structure. Here's the exact format that gets claims adjusted.
⚠️ Vague supplement requests get denied. Itemized requests with documentation get paid. The structure of your letter matters as much as the numbers.
For the complete supplement process—from documenting gaps to escalation—see our supplement master guide.
Insurance adjusters process dozens of claims weekly. They prioritize supplements that are easy to evaluate: clear itemization, attached proof, and professional formatting. Supplement letters that are emotional, vague, or poorly organized get pushed to the bottom of the pile—or denied with a form letter.
When you write a supplement that mirrors the format insurers use internally, you signal competence. That significantly increases the likelihood of a full or partial payment. Policyholders who use structured supplement templates recover an average of $12,000-$28,000 more than those who submit informal emails.
The itemized schedule is what gets you paid. For each additional amount, include:
Example format:
Item 1: Overhead and Profit (10% O, 10% P) on subs — $4,200. Supporting: Contractor estimate, industry standard per policy. Attached.
Item 2: Code upgrade - roof decking 7/16" to 1/2" OSB — $1,850. Supporting: Building code section 202.1, Contractor B estimate. Attached.
At least two detailed estimates showing complete scope and market pricing
Date-stamped images of damage supporting each disputed item
Building code citations, permit fee schedules, engineering if required
Never submit a supplement without attachments. The letter makes the case; the attachments prove it. Carriers will not pay based on your word alone.
Before writing, compare the carrier estimate to contractor estimates. Document every missing item, underpriced line, and quantity error. Create a spreadsheet or use comparison software. Your itemized schedule comes directly from this analysis.
List each supplement item with description, amount, and document reference. Use a table format for clarity. Total the column. This schedule becomes the heart of your letter.
Add the header, subject line, intro paragraph, and closing. Keep the letter itself to one page. The schedule and attachments do the heavy lifting.
Assemble contractor estimates, photos, code docs in PDF. Send via email to your adjuster and claims email. Consider certified mail for a paper trail. Note the date for follow-up.
Our supplement letter templates, estimate comparison tools, and documentation checklists help you demand what you're owed—without paying 10-15% to a public adjuster.
Start Your Claim ReviewThreats and anger get your file flagged, not paid. Maintain a professional, factual tone. Let the documentation carry the weight.
"We need another $20,000" with no itemization will be denied. Every dollar must tie to a specific line item with supporting proof.
When applicable, cite your policy's obligation to pay for necessary repairs, code upgrades, or market rates. Policy language strengthens your position.
A supplement letter must include your policy and claim number, a clear subject line, an itemized list of each additional amount requested with line-by-line documentation, supporting evidence (contractor estimates, photos, code citations), and a professional tone. End with the total additional amount and a reasonable response deadline.
Supplement letters typically run 2-4 pages plus attachments. The letter itself should be concise; the power is in the itemized schedule and supporting documentation. Each line item should have a description, requested amount, and reference to the attached proof.
You can write a supplement letter yourself. Most successful supplements use professional templates and clear documentation—no legal degree required. Lawyers are only necessary when the carrier acts in bad faith or you're considering litigation.
Carriers expect a formal business letter with claim number in the subject/reference line, an itemized schedule matching their estimate format (line numbers if available), contractor estimates, photos, and any code or permit documentation. PDF format is standard.
Compare your carrier estimate line by line to contractor estimates. For each missing item, use the contractor's price. For underpriced items, document the market rate and request the difference. Sum all line items for your total supplement amount.