How to Write a Construction Change Order

A change order is a written amendment to a signed construction contract that documents a scope variation, the resulting price adjustment, and the resulting schedule impact. Without a change order, the original contract scope and price stand. Anything outside the original scope is at risk of being unpaid, because the client can argue the work was not authorized. Verbal change requests are the number one source of small contractor unpaid balances. The fix is structural: every variation, no matter how small, goes through the change order workflow, with a signature before the work begins.

Use plain language a homeowner can understand. 'Add 12 linear feet of crown molding in the dining room, paint to match existing.' 'Replace 14 existing duplex receptacles with USB-C combo receptacles in the kitchen and living room.' 'Reroute supply line for new island sink, 8 feet of 1/2 inch PEX, one new shutoff valve.' Avoid jargon and three-letter acronyms. The description must be specific enough that a third party (a court, a lien claim, a future home inspector) can identify exactly what was added or changed. Vague descriptions like 'extra electrical' or 'kitchen upgrade' lose disputes.

Show labor and material as separate lines, with quantity and unit price. Material example: '14 USB-C combo receptacles, $32 each, $448.' Labor example: 'Replace receptacles, 0.75 hours each at $95 per hour, $997.50.' Apply your standard markup as a separate line, not buried in unit price. Total the change order, and clearly mark whether it is an add (positive) or a deduct (negative). Then state the original contract amount, the change order amount, and the new contract total in three lines at the bottom.

• Labor line with quantity, hours per unit, hourly rate.
• Material line with quantity and unit price.
• Markup line as a separate line item.
• Total: positive (add) or negative (deduct).
• Original contract + change order = new contract total.

Every change order names the schedule impact in days, even if zero. 'Schedule impact: 0 days' is a valid statement that the change does not extend completion. 'Schedule impact: +3 working days' lets the client see why the project finish date is now Friday March 19 instead of Tuesday March 16. Schedule impact prevents the client from claiming later that the change was free in days even if not free in dollars. State the impact in working days, not calendar days, since weekends are nonproductive.

A signed change order before work begins prevents the most common dispute: 'I never approved that, I am not paying for it.' Verbal go-aheads, emojis in text messages, and shrugs at the job site are not legally enforceable as approvals in most jurisdictions. The change order must be written, signed, and dated by the client before the work starts. If the client refuses to sign, you have a decision to make about whether to proceed; usually the right answer is no. Performing unauthorized work and then trying to collect is a losing position, both legally and in client relations.

Sequential numbering by project, starting at CO-001 and incrementing for each subsequent change. Reference the original contract by date and project address on every change order. Some contractors number across all projects (CO-2026-0145), which is fine for accounting but harder to look up by project. Sequential per project keeps the audit trail clean. The numbering also helps when a project ends up with 6 to 12 change orders (common on remodels), since each can be referenced by short ID rather than describing the change again.

A project workspace that ships change orders inline with the original bid eliminates the document scramble that derails most change order workflows. When the contract, photo log, and milestone schedule already live in one place, drafting a change order is a 5 minute task instead of a 30 minute exercise in pulling files. ContractShield routes change orders through the same workspace as the bid, with e-sign for the client and automatic update to the milestone schedule and total contract value. The default workflow eliminates the verbal-approval trap.