A lot of roofing contractors know they should be supplementing. Fewer know how to write one that actually gets approved. The difference usually comes down to documentation, specificity, and tone.
Here's what a supplement that moves through the process looks like.
Why Xactimate Line Item Codes Matter
Xactimate is the estimating platform most carriers use. When you submit a supplement, you're asking the carrier to add or adjust line items within that system. Using the correct Xactimate codes in your submission removes ambiguity and makes it easy for the adjuster to locate and process each item.
A supplement that references specific codes communicates that you understand the system and have done the work. One that's vague forces the adjuster to figure out what you're asking for, which slows everything down.
Worth Noting
Supplements that include specific Xactimate codes, code citations, and photos get approved faster. Vague requests create back-and-forth that delays the whole claim.
Citing Building Codes and Manufacturer Specs
When you're requesting a line item that the adjuster didn't include, you need to explain why it's required. Local building codes are one of the strongest justifications available. If your jurisdiction requires ice and water shield, cite the code section. If manufacturer specs require a specific underlayment for warranty compliance, reference the spec sheet.
These citations do two things. They give the adjuster something concrete to approve against. And they show the carrier that the request isn't subjective — it's a compliance requirement.
Using NOAA Storm Data
NOAA storm event data is publicly available and highly useful for claims involving hail or wind. Pull the storm report for the event date and affected area. Include hail size, wind speed, and coverage area. This data directly supports your claim that storm damage occurred and helps justify the scope.
What a Complete Supplement Package Looks Like
A well-built supplement package includes the original estimate with each disputed item flagged, your supplement request with Xactimate codes and quantities, photos supporting each line item, relevant code citations or manufacturer specs, NOAA data if applicable, and the revised total.
The goal is to make the adjuster's job easy. Every question they might ask should be answered before they ask it.