A supplement letter is the document that determines whether your additional claim request gets approved or denied. An adjuster reviewing your supplement has seen hundreds of these. The ones written clearly, organized logically, and backed by documentation get processed. The ones that are vague, disorganized, or missing supporting evidence get rejected or delayed.
This guide covers exactly how to write a roofing supplement letter — including a full template you can adapt for any claim.
What a Supplement Letter Is (and Isn't)
A supplement letter is a formal written request to the insurance carrier for additional payment beyond the original approved estimate. It is a business document — not a complaint, not a negotiation in the casual sense, and not a place for emotional appeals.
The adjuster's job is to pay what the policy covers for legitimate documented losses. Your job is to demonstrate, in writing, that the items you're requesting are legitimate, documented, and within the scope of the loss. That's it. Keep it professional, specific, and evidence-based.
Before You Write: Gather Your Documentation
A supplement letter without supporting documentation is just a request. A supplement letter with supporting documentation is a demand backed by evidence. Before you write the letter, have the following in hand:
- Original claim number and approved estimate — you'll reference both
- Adjuster's name and contact information
- Itemized list of what you're supplementing — each item with its justification
- For code upgrades: printed local code language or a letter from the building department
- For material cost differences: current supplier invoice or price quote
- For O&P: brief explanation of the scope that requires general contractor coordination
- For permit fees: actual permit receipt or municipal fee schedule
- For additional damage: photos taken during tear-off showing condition before covering
- Xactimate line item numbers for each supplement item, if applicable — this makes the adjuster's job easier and speeds approval
The Supplement Letter Template
Use this template as a starting point. Customize it for each claim — never send a generic form letter. Adjusters notice.
[Your Company Letterhead]
Date: [Date]
To: [Adjuster Name]
Insurance Company: [Carrier Name]
Claim Number: [Claim #]
Insured: [Homeowner Name]
Property Address: [Address]
Original Estimate Date: [Date of original approved estimate]
RE: Supplement Request — [Claim #] — [Homeowner Last Name] — [Property Address]
Dear [Adjuster Name],
We are the roofing contractor of record for the above-referenced claim. We are submitting this supplement request for items not included in, or underpriced in, the original estimate dated [date]. These items are necessary for a complete and proper restoration of the property to pre-loss condition in compliance with local building codes and manufacturer installation requirements.
Please find our supplement items detailed below:
Supplement Item 1: [Item Name]
Amount Requested: $[X]
Xactimate Line Item: [Line item code, e.g., RFG DRIP]
Justification: [Explain why this item is necessary. Be specific. Reference code, manufacturer specs, or the original estimate if it was omitted.]
Supporting Documentation: [Reference attached document — e.g., “See attached: City of [City] building permit fee schedule dated [date]”]
Supplement Item 2: [Item Name]
Amount Requested: $[X]
Xactimate Line Item: [Line item code]
Justification: [Specific justification]
Supporting Documentation: [Reference attached document]
[Continue for each supplement item]
Total Supplement Request: $[Sum of all items]
We have attached all supporting documentation referenced above. We respectfully request written approval of this supplement within [10–15] business days. Please contact me directly at [phone] or [email] with any questions or if additional documentation is needed.
Thank you for your attention to this matter.
Sincerely,
[Your Name]
[Your Title]
[Company Name]
[Phone]
[Email]
[License Number, if applicable]
How to Write Each Supplement Item Section
The body of your letter is where most contractors go wrong. Here's how to write each item to maximize approval speed.
Be Specific About What Was Missed
Don't write: “The estimate was missing some items.”
Write: “The original estimate dated [date] did not include drip edge installation on the rake edges. Per the original scope of loss, only eave drip edge was included (line item RFG DRIP, 148 LF). The property has 94 LF of rake edge requiring drip edge installation per [City] building code Section [X].”
Reference the Specific Code
Adjusters can't deny a code-required item. If your supplement is based on a code requirement, cite the specific code:
“Per [City/County] building code, ice and water shield is required on the first 36 inches from the eave edge in climates where average January temperatures are below 25°F. This property's jurisdiction requires this protection. See attached: [City] Building Code Section R905.1.2. The original estimate did not include ice and water shield.”
Attach a Price Quote for Material Differences
If you're supplementing because material prices have risen since the original estimate, attach your current supplier invoice or a written quote. The adjuster needs documentation — not your word for it.
O&P: Explain the Coordination Required
Overhead and Profit (O&P) is often the most valuable supplement item and the most commonly contested. The basis for O&P is that general contractor coordination is required — managing multiple trades, permits, inspections, material deliveries, and schedule coordination. Write it this way:
“This project requires general contractor oversight including: pulling the building permit and scheduling inspections, coordinating material delivery with crew scheduling, managing tear-off, decking repair, and installation subcontractors, and supervising installation to manufacturer specifications required to maintain the warranty. We are requesting 10% overhead and 10% profit (O&P) in line with industry standard Xactimate guidelines for projects requiring general contractor coordination.”
Common Supplement Items and How to Word Them
Starter Strip (Omitted from Estimate)
“Starter strip was not included in the original estimate. Per [Manufacturer] installation instructions (attached), starter strip is required along all eave and rake edges prior to shingle installation to maintain manufacturer warranty. Property has [X] LF of eave edge and [X] LF of rake edge requiring starter strip. Total: [X] LF at $[rate]/LF = $[total].”
Permit Fees
“[City] building permit fee for roofing projects of this scope is $[amount], per the attached permit fee schedule. The original estimate did not include this cost. Permit receipt attached.”
Ridge Cap (Labor Underpriced)
“The original estimate included ridge cap material but not installation labor. The property has [X] LF of ridge and [X] LF of hip ridge requiring cap shingle installation. At [rate]/LF for installation, total labor is $[amount].”
Additional Decking (Discovered During Tear-Off)
“Upon tear-off, [X] sheets of roof decking were found to be deteriorated beyond acceptable condition (photos attached). Per [City] building code, deteriorated decking must be replaced prior to new roofing installation. [X] sheets × $[rate]/sheet = $[total]. Photos of the decking condition prior to replacement are attached.”
Following Up on a Submitted Supplement
Submitting the letter is step one. Following up is what actually gets supplements approved. Without follow-up, supplements sit in an adjuster's queue indefinitely.
- Day 10: Email follow-up — “Following up on the supplement request submitted [date] for claim [#]. Please let me know if any additional documentation is needed.”
- Day 17: Phone call to adjuster. Document the call in your notes.
- Day 25: Escalate to the adjuster's supervisor if no response. Professional, polite, persistent.
Track every supplement in a system that shows you the submission date, status, and next follow-up date. When you have 30+ active supplements across multiple carriers, this is the only way to make sure nothing falls through.
What Not to Put in a Supplement Letter
- Emotional language: “The adjuster clearly didn't know what they were doing” — this antagonizes the person deciding your request
- Vague requests: “We need additional money for extra work” without specifics
- Missing documentation references: If you say “see attached” but don't attach it, the adjuster will wait rather than follow up
- Multiple unrelated jobs in one letter: One letter per claim, always
- Handwritten letters: Typed, on letterhead, formatted professionally
Key Takeaways
- A supplement letter is a business document — keep it professional, specific, and evidence-based
- Document every item before you write the letter — the letter references the documentation, not the other way around
- Use specific language: code citations, Xactimate line item references, attached invoices
- Follow up consistently — submitted supplements without follow-up stall indefinitely
- Track every open supplement in a system so nothing expires or gets forgotten