What Is a Construction Change Order and When Do You Need One

Two terms show up in change order conversations, and confusing them causes problems.

A Change Order Request (COR) is what the contractor submits. It formally outlines the change in scope of work, cost, and schedule impact. Whether the change was requested by the client, caused by unforeseen conditions, or triggered by something else, the contractor is responsible for clearly outlining the change and presenting the costs in the COR.

Once approved, the customer issues a change order that formally updates the contract value. On larger projects, a COR sent by a general contractor to the owner is typically a package bundling multiple subcontractor CORs together.

The COR is your ask. The change order is the answer. You need both.

A construction change order can be used for five categories of change:

1. Change in scope. The owner decides to add a second bathroom to a remodel, or remove a wall that was not in the original plan. The change order documents the new work and communicates it to all parties.

2. Change in schedule. A material delay pushes the timeline back three weeks, or the client wants to accelerate the finish date. The change order updates the schedule and adjusts the project cost accordingly.

3. Change in materials. The specified tile is discontinued, or the client upgrades from laminate to hardwood. A change order specifies the new materials and adjusts the cost.

4. Change in site conditions. You open a wall and find asbestos. You dig a foundation and hit rock. Environmental and geotechnical problems, or errors and omissions in the original contract, all qualify. The change order documents the corrective action.

5. Change in regulations or codes. A building code update takes effect mid-project, or a zoning variance imposes new requirements. The change order records the necessary revisions.

Each of these triggers a cost change, a schedule change, or both. Without documentation, you absorb the difference.

Six elements make a change order enforceable and billable.

A clear description of changes. This is not "misc. extra work." It should be a detailed description of what is changing, and those changes must be within the scope of the original contract.

The parties involved. Owner, contractor, and any relevant subcontractors. Change orders are not valid until signed by all parties involved.

Updated total contract price. Include the dollar amount by which the price is being raised or lowered and the updated total. The cost breakdown must itemize labor, material, equipment, and any other categories, clearly showing quantities and unit rates.

Markup disclosure. A clear breakdown of overhead, profit, tax, insurance, and bonding applicable to the project. Burying markup in inflated line items erodes trust. Disclosing it builds it.

Revised completion date. Include the number of days the completion date is changing and the new completion date.

Revised payment schedule. If the payment schedule from the original contract will be impacted, a new payment schedule needs to be detailed in the change order. This is the element most contractors leave out, and the one most likely to cause a payment dispute. If you are working from a contractor payment schedule, the change order needs to update it.

For projects requiring an architect's signature, the standard form is AIA Form G701 from the American Institute of Architects.

The process begins when one party identifies the need for a change and brings it to the other parties' attention. From there:

Step 1: Identify the need. Something changed. Document what happened and why the original contract no longer covers it.

Step 2: Contractor writes a proposal. The proposal includes estimated costs for the requested changes and outlines any resulting changes to the completion date and payment schedule. Start from a contractor estimate template if you need a format for the cost breakdown.

Step 3: Negotiate. The owner reviews the proposal. Numbers get adjusted. Scope gets refined. This is where clear itemization pays off, because vague line items invite negotiation on everything.

Step 4: Prepare the change order. Once the details are agreed upon, the formal document is completed with all six elements listed above.

Step 5: Sign. Each party acknowledges the document with their signature. Until this step happens, the change order is not legally valid.

Speed matters here. Every day between identifying a change and getting a signature is a day you are either working at risk or waiting to start.

An unsigned change order means you cannot bill for the work. A sloppy or missing COR can result in lower approval values or flat-out rejection. If you spend money on labor and materials and the COR does not adequately describe and cover those costs, you lose that money.

The COR also protects the contractor's right to be paid for extra work and helps the client understand what they are paying for. When these documents are unclear or vague, it leads to strained relationships and mistrust.

Late submissions compound the problem. When a subcontractor is late submitting a COR, it holds up the approval of all other subcontractors on the job because the owner wants a complete picture of changes before approving anything. One late COR creates cash flow risk for every sub on the project.

The stakes are not abstract. Challenges with the COR process are the number one reason for broken business relationships, lawsuits, and in many cases subcontractors going out of business.

Subcontractors who adopt clear, consistent change order formats see dramatic improvements in approval times. Faster approval means faster invoicing. Faster invoicing means faster payment. For the full collection system once the invoice goes out, see our guide on how contractors get paid faster.

A change order can modify the original contract, but it cannot replace it. Courts typically do not allow change orders to exceed the scope of the original project or to defeat the purpose of the original contract. That original contract scope is typically set by a signed quote — for clarity on which document is binding, see our guide on the difference between an estimate and a quote.

In practice, this means you cannot use a change order to turn a kitchen remodel into a full home addition. If the changes are so extensive that the original contract no longer describes the project, you need a new contract.

This also protects contractors. If a client tries to use a change order to fundamentally alter the deal (same price, triple the work), the original contract's scope defines the boundary.

The signed change order authorizes the work. It does not pay for it. You still need to invoice the revised amount and track payment against the updated schedule. Your invoice workflow picks up here — the change order number and approved amount go on the next invoice.

If you are billing in phases, the change order amount gets folded into your progress billing structure. If it is a single milestone, it gets its own line on the next invoice. For SBA guidelines on managing contracts and business finances, the Small Business Administration provides best practice resources for small contractors.

Either way, use a construction invoice template that references the change order number, the approved amount, and the revised total contract value. The client should be able to trace every dollar on the invoice back to either the original contract or a signed change order.

If payment slows down after the change order is approved, automated invoice reminders keep the follow-up consistent without you having to chase it manually. The change order already established what is owed and when. The reminder enforces it.