How to Write an Xactimate Supplement That Gets Approved

Almost every restoration job changes after the first estimate. Demolition opens a wall and finds wet insulation two bays past where anyone expected. A floor that looked like one layer turns out to be two. An inspector requires something the original scope never mentioned. A supplement is how you get paid for that change — and it is also where a lot of restoration revenue quietly disappears, because the request reached the adjuster without the reason attached.

This guide covers when to supplement, what to gather before you write, how to build the supplement itself, and how to follow up so it gets paid.

What a supplement is

A supplement is a request to add to or revise an approved estimate because the scope, the quantities, or the pricing changed after the original was written. In insurance restoration it is usually written in Xactimate, because that is the format the carrier's adjuster works in. A supplement does not replace the original estimate. It explains what changed and why, item by item.

The adjuster reviewing it is asking one question: can I justify paying this to whoever reviews my file? Your job is to make the answer yes without a phone call.

Common reasons to supplement

• Hidden damage. Damage revealed during demolition or drying that could not be seen at inspection: wet insulation, rotted subfloor, mold behind cabinets.
• Missed line items. Work that was always required but was not on the original estimate: content manipulation, floor protection, cleanup, monitoring days.
• Quantity changes. Measurements that changed after a full scan or after demo: more drywall, a larger affected floor area.
• Code requirements. Work required by local building code when damaged materials are replaced, where the policy covers it.
• Extended drying. More equipment days than first estimated, backed by daily readings.
• Pricing corrections. A line item priced against the wrong price list or in the wrong unit.

Before you write: gather the evidence

A supplement is only as strong as the file behind it. Before you open the estimate, collect the following.

• Photos of every added item, before, during, and after, labeled by room. A photo of the open wall with wet insulation is worth more than any paragraph.
• Moisture readings and drying logs for any added drying or demolition, including the dry standard and daily readings. Our guide to carrier-defensible drying logs lists what a complete log includes.
• Measurements from a scan or an updated sketch, so quantities match the property instead of an estimate made from the doorway.
• The code section, inspection note, or manufacturer instruction behind any code or installation item.
• Field notes recording who found the issue, when, and what they saw, written the same day.

If an item has no evidence, it is not ready to submit. Go back and get the evidence, or leave the item off.

How to write the supplement

Keep the original estimate intact

Build the supplement as a revision of the approved estimate rather than starting over, so the adjuster can see exactly what was added or changed. Never quietly re-price items that were already approved.

Justify every line item

Give each added or changed line a short written reason in its notes: what was found, where, and which photo or reading proves it. A note like "Flood cut 2 ft, rooms 2 and 3, per moisture readings 10/14, photos 22–31" gets approved faster than a line with no note at all.

Lead with a one-page summary

Put a cover summary on top: the claim number, the reason for the supplement in two or three sentences, the total change, and a list of added items with their reasons. Many adjusters read the summary first and open the detail only if something looks off. Let the summary do the work.

Cite the standard where it applies

For water mitigation, the IICRC S500 is the reference adjusters know. For mold remediation, it is the IICRC S520. When a line item exists because a standard calls for it, say so. A standard is not policy language, but it shows the work was necessary and done the accepted way.

Separate the likely disputes from the obvious items

If a few items are likely to draw pushback — overhead and profit, code upgrades, an unusual equipment count — keep them clearly separate so the undisputed items can be approved and paid while the rest is discussed.

How to submit and follow up

• Use the channel the carrier expects. For carrier program work that is often XactAnalysis. Otherwise it is usually the desk adjuster or field adjuster on the claim. Ask at the start of the job.
• Raise it as soon as you find it. When you find hidden damage, tell the adjuster right away. Many carriers and programs expect notice, and sometimes approval, before the scope expands. A supplement that arrives weeks after the work invites the question of why no one mentioned it sooner.
• Follow up on a schedule. Put a follow-up date on every open supplement and check them weekly. A short "checking on the supplement from 10/14 — is there anything else you need?" moves more files than a frustrated email after a month of silence.
• Answer pushback in writing, line by line. When an item is questioned, respond with the evidence for that item and keep it factual.
• Track the result. Record what you requested and what was approved. Supplement recovery rate is one of the restoration KPIs that shows whether your documentation is improving.

Common mistakes that get supplements cut

• Re-sending an entire revised estimate with no summary of what changed.
• Adding items with no photo, no reading, and no note.
• Mixing new items with re-priced items that were already approved.
• Waiting until the end of the job to mention hidden damage.
• Arguing tone instead of evidence when an item is denied.

Where software helps

Supplements fall apart when the evidence is scattered: photos on a technician's phone, readings in a spreadsheet, measurements on a sketch pad, and the estimate in Xactimate. Assembling the package becomes its own project, and on a busy week it doesn't get done.

Riivet keeps the scan, photos, drying logs, and estimate on the same job, so the evidence for a supplement is already attached when you need it. Its AI negotiations engine drafts supplements and carrier responses from that job data and industry standards, for your team to review and send. For more on how AI fits into claims work, read AI-powered negotiations on insurance claims, and for how estimates move between platforms, see what Xactimate integration actually means.

The takeaway

A supplement gets approved when the adjuster can see what changed, why it changed, and the proof, without having to call you. Keep the original estimate intact, justify every line with a note and a photo, lead with a one-page summary, cite the standard where it applies, and follow up on a schedule. Do that every time, and supplements stop being a fight and start being paperwork.