How Xactimate Supplementing Works: A Complete Guide for Roofing Contractors
By Kyle Hamrick · March 22, 2026
If you've been doing insurance restoration work for more than a few months, you've already noticed it: the carrier's initial estimate never covers everything. There are missing line items, incorrect measurements, low labor pricing, and code upgrades that simply don't appear. That gap between what the carrier pays and what the job actually costs is called the supplement — and recovering it is one of the highest-leverage things a roofing contractor can do for their business.
What Is a Supplement in Roofing Insurance Claims?
A supplement is a formal request to the insurance carrier to increase the original claim payment. It's not an appeal, and it's not a dispute — it's a standard part of the insurance restoration process. Carriers expect supplements. Their adjusters are trained to write lean initial estimates knowing that contractors who know what they're doing will supplement back.
The supplement includes a revised or expanded Xactimate estimate that documents every line item that was missed, underpriced, or incorrectly calculated in the carrier's original scope. This is where licensed adjuster expertise becomes critical — because writing a supplement that gets approved requires knowing exactly how carriers build their estimates and exactly what language they accept.
What Is Xactimate and Why Does It Matter?
Xactimate is the industry-standard estimating software used by insurance carriers to calculate claim payments. Almost every major carrier — State Farm, Allstate, USAA, Travelers, Liberty Mutual — uses Xactimate as the basis for residential and commercial property claims. If your estimate isn't in Xactimate, carriers won't process it. Period.
Xactimate assigns specific line item codes to every scope of work: tear-off, felt, shingles, ridge cap, drip edge, ice and water shield, flashing, skylights, gutters, and hundreds more. Each line item has a unit price that varies by geographic market and is updated quarterly. Knowing which line items apply to a given job, what the current pricing is, and how to document why each item is necessary is the core skill of supplement writing.
What the Supplementing Process Looks Like
The process starts when you send us the carrier's initial estimate along with your documentation — inspection photos, measurements, roof report, and scope notes. Our team reviews the carrier estimate line by line, compares it against current Xactimate pricing for your market, checks for missing code-required items, and identifies every scope omission.
We then build a revised Xactimate estimate that includes every recoverable line item, documented with clear notes explaining why each addition is required. That supplement package goes back to the carrier's desk adjuster, who reviews it against the original and either approves the additions, negotiates on specific items, or in rare cases requests additional documentation.
The result: a higher final payment that reflects what the job actually costs to do properly. Our clients typically see supplement recoveries of $1,500 to $8,000+ per claim depending on the scope and the carrier.
Why Hire a Professional Supplement Company?
Writing an effective supplement isn't just entering line items into software. It requires knowing what a carrier will accept, how to phrase justification notes, what documentation supports each claim, and how to push back when a desk adjuster rejects an item. The Estimate Company is founded and operated by licensed insurance adjusters — meaning we know how the other side works because we've worked on it.
Our 24-hour turnaround means you're not waiting a week to find out what you're owed. And our 500%+ ROI guarantee means if you don't recover more than you spend on our services, you don't pay.