If you’ve ever gone through an insurance restoration claim, you may have heard your contractor mention something called a “supplement.” It’s one of the most important — and most misunderstood — parts of the insurance restoration process. Here’s a plain-language explanation of what it is and why it matters for your project.
Start with the Basics: The Initial Estimate
When you file a claim, your insurance company sends an adjuster to inspect the damage and produce an estimate. This estimate outlines what the carrier believes the repair will cost, broken into individual line items. It’s the starting point for the claim — but it’s rarely the final word.
Adjusters work quickly. They use estimating software — most commonly Xactimate — and they may inspect your property for an hour or less. In that time, it’s nearly impossible to catch every damaged component, every code-required upgrade, and every legitimate line item that belongs in the scope. Items get missed. Quantities get underestimated. Whole categories of work get omitted.
What Is a Supplement?
A supplement is a revised or additional estimate submitted by your contractor to the insurance company after the initial estimate is issued. It documents the items that were missed, the quantities that were wrong, and the line items that legitimately belong in the scope but weren’t included in the carrier’s first pass.
This is not an attempt to inflate a claim or get something for nothing. A supplement is your contractor saying: “Here’s what was left out of the original estimate, and here’s the documentation to support it.” It’s a normal and legitimate part of the insurance restoration process.
What Typically Gets Added in a Supplement
- Overhead and Profit (O&P) — The standard 10/10 markup (10% overhead, 10% profit) that general contractors are entitled to charge when coordinating multiple trades. This is the single most commonly omitted line item in carrier estimates.
- Code upgrades — Michigan building code requires that replaced components meet current code standards, even if the original didn’t. Ice and water shield, drip edge, ridge ventilation, and other code-required items are frequently missing from first estimates.
- Additional damaged components — Damage that wasn’t visible during the adjuster’s inspection, or components that were overlooked.
- Correct quantities — Roof squares, linear feet of gutters, squares of siding — these are sometimes underestimated in the original scope.
- Permit fees — Required for most structural repairs in Michigan and a legitimate project cost.
How the Process Works
Your contractor prepares the supplement with line-by-line documentation — measurements, photos, code references, and pricing from the current Xactimate price list. This gets submitted to the insurance company’s desk adjuster, who reviews it and either approves, partially approves, or denies the additional items.
Good contractors negotiate. They don’t just submit and accept whatever comes back. If a legitimate line item is denied, they push back with documentation. This back-and-forth is normal and expected in insurance restoration.
Why This Matters for You
The difference between what a carrier initially offers and what a properly supplemented claim pays out can be substantial — sometimes tens of thousands of dollars on a larger loss. That gap is the difference between a restoration that’s done correctly and one that cuts corners because the budget ran out.
Your contractor should be doing this work on your behalf. If they’re not, ask them why.
Supplement negotiation is a core part of what Phase III Construction does on every project. We don’t accept the first estimate as the final answer — we document everything, push for everything that belongs in the scope, and fight to get your claim paid correctly. Call us at (734) 237-7322 to talk through your claim.