Change Orders: How to Price, Approve and Document Them Without Blowing the Budget

The framing crew finds that the beam shown on the drawings does not fit the stair opening. The foreman says it is a quick fix and starts on it. Two weeks later a pay application arrives with a line called "Framing revisions" and a number nobody remembers agreeing to. The owner thought it was included. The contractor thought it was approved on site. Neither has anything in writing.

Nothing about this is unusual, and nobody has to be acting in bad faith for it to go wrong. Change orders are where a clean contract turns into a disputed one, because they are the point where money, time and memory meet. Handled in a consistent way, they are routine paperwork. Handled by conversation, they become the largest source of argument on the job.

Why change orders are where margin and disputes hide

The original contract price was competed, reviewed and agreed. A change is usually priced by one party under time pressure, after the work is already visible and often already under way. Whoever is weaker on documentation pays for it.

For the owner, the risk is a budget that grows in small steps, each one reasonable on its own. For the contractor, the risk is the reverse: work performed, never authorized in writing, and then unpaid. For a private builder without a project manager, the risk is both at once.

Three things make this worse than it looks:

• Small items are not tracked. A few modest changes rarely feel worth a formal process, yet together they can move the final cost materially.
• Time is forgotten. A change that costs little can still push back a following trade, and that delay costs more than the work itself.
• Agreement is verbal. A verbal "go ahead" is remembered differently by each side within a month.

Scope gap or true change?

Before pricing anything, decide what you are looking at. These are different problems with different owners.

• Scope gap. The work was always needed to deliver what the documents describe, but nobody priced it clearly. A bid that left out a required item usually stays with the party who wrote the bid, depending on the contract wording.
• True change. The owner asks for something different from what the contract documents describe: a different finish, an added room, a revised layout.
• Unforeseen condition. The ground, existing structure or hidden services differ from what the documents indicated. Whether this is a change usually depends on what the contract says about differing site conditions and who carries that risk.
• Design error or conflict. Drawings contradict each other or the specification. The contract's order-of-precedence clause matters here.

What to ask: Which document describes this work? Is it shown, specified, or silent? If the documents conflict, which one governs under the contract? A written answer to those three questions settles most arguments before any price is discussed.

Choosing the pricing basis

There are three common ways to price a change, and the contract often says which applies. If it does not, agree on the basis before work starts.

Unit rates

If the contract includes a schedule of rates for the kind of work involved, such as per cubic metre of concrete or per square metre of drywall, the change is quantity times rate. This is the cleanest basis because the price was agreed before anyone knew the change was coming.

Lump sum

A fixed price for a defined piece of work. It suits changes that can be scoped before they start. The contractor carries the risk of overrun, so a careful contractor will price in a contingency. Ask for a breakdown into labour, materials, equipment and subcontractors so you can see what you are paying for.

Time and materials (T&M)

Used when the scope cannot be defined in advance, for example opening up an existing wall. It is flexible but open-ended, so it needs controls:

• a not-to-exceed figure or a point at which the contractor must stop and re-confirm;
• agreed hourly rates for named roles, and agreed treatment of equipment and materials;
• daily sign-off of timesheets and delivery tickets by someone with authority;
• a clear statement of what markup applies to what.

Markup and overhead: read the contract, not the invoice

Disputes over markup are common because the contract language is often thin. Find these points in the contract before a change arises:

• Is there a stated percentage for overhead and profit on changes, and does it differ for additions and deductions?
• Does the markup apply to subcontractor work, and can the general contractor add its own markup on top of the subcontractor's?
• Are some costs excluded from markup, such as insurance, bonds, permit fees or taxes?
• Do deductive changes carry the same markup as additive ones? If a change removes work, the owner should expect credit for it.

If the contract is silent, do not assume a number. Agree one in writing for that change and note that it applies to that change only.

Time impact belongs in the same document

A change order that states only a price is incomplete. Every change should state its effect on the schedule, even if the answer is "none."

• Does the changed work sit on the critical path, or does it have float?
• If time is added, is it a day count, a revised completion date, or both?

If the document says nothing about time, a contractor may later claim an extension on top of the price, and the owner will have difficulty arguing it was agreed to be included. Where possible, include a sentence confirming that the price and time stated are the full adjustment for that change.

Written authorization before work, and notice requirements

Most construction contracts require a written instruction or signed change order before changed work starts, and many set a deadline for the contractor to give notice that something is a change. Those deadlines can be short. Standard forms such as the AIA A201 general conditions and the ConsensusDocs family contain change and claim procedures, and international forms such as FIDIC have their own variation procedures. The notice periods, who can sign, and what happens when a deadline is missed differ between them and between jurisdictions. Check the current version of the form in your contract, and what your local law says, rather than relying on memory.

In practice, a workable routine looks like this:

1. The person who notices a possible change writes it down the same day: what, where, why, and which document is affected.
2. The contractor sends a priced proposal with a time statement within the contract's notice period.
3. The owner or the owner's representative reviews, negotiates if needed, and signs.
4. Work on the changed scope starts only after signature, except where safety or weather protection requires immediate action, and even then a short written confirmation should follow.

Confirm who has authority to sign. A site engineer's verbal instruction may not bind an owner, and an owner's casual comment on site may not be the written direction the contract requires. Both sides should know the signatories before the first change.

Constructive change: when no one signed but the work happened

A constructive change is a legal idea in some jurisdictions: the owner, through conduct or informal direction, effectively requires work beyond the contract, and the contractor may seek payment even without a signed change order. Whether it applies, and how strictly notice rules are enforced against the contractor, depends on the contract and the law where the project sits. Do not assume the doctrine rescues a missed notice, and do not assume it cannot be used against you.

Warning signs on an owner's side are emails that tell the contractor to "just do it", or rejecting work that meets the documents.

The remedy is the same for both parties: respond in writing quickly, say whether the item is or is not a change, and reserve rights where you disagree.

Track the cumulative effect

Each change looks small. The total is what matters. Keep a running change log and review it at every progress meeting. It should show, for every item:

• change number, date raised, description and the document it affects;
• status: proposed, approved, rejected or pending;
• price, markup, and time effect;
• running total of approved changes, and pending exposure from proposals not yet decided;
• revised contract sum and revised completion date.

Compare the running total with your contingency, and if you are financed, with whatever the lender will allow.

One-page change order checklist

1. Which contract document covers this work? Shown, specified or silent?
2. Scope gap, true change, unforeseen condition or document conflict?
3. Who is the right party to bear the cost under the contract?
4. Is the pricing basis agreed: unit rate, lump sum, or T&M with a cap?
5. Do markup and overhead follow the contract, and are credits for removed work shown?
6. Is the time effect stated, including "no change" where that is the case?
7. Was notice given inside the contract deadline, and is there proof of the date?
8. Has someone with authority signed before the work began?
9. Is the change added to the log with a revised contract sum and completion date?
10. If financed, does the lender need to approve or be told?

Where an independent document review fits

Many change order problems start earlier, in the documents: drawings that conflict with the specification, a cost estimate with quantities that do not match the design, or contract wording on changes that is vague about markup, notice or authority. An independent review can surface those points before the first change arises, or give a second reading of a proposed change order against the contract and drawings.

MEXUM is a service that reviews design, cost and contract documents and returns a reasoned conclusion as a PDF within 48 hours. It identifies what the documents say, where they conflict or leave gaps, and what questions to raise. It does not replace your lender, engineer, inspector or lawyer. Decisions on approval, safety, compliance and legal rights remain with them.

This article is general information and not legal or financial advice; check your contract and the rules in your jurisdiction, and consult a qualified professional for your situation.

Frequently asked questions

Why do change orders cause so many disputes on construction projects?

Change orders are where money, time and memory meet. A change is usually priced by one party under time pressure, often after work is visible or under way. Small items go untracked, delay costs are forgotten, and verbal approvals are remembered differently by each side within a month, so whoever documents less tends to pay.

How do I tell whether something is a scope gap or a true change?

Ask which contract document describes the work, whether it is shown, specified or silent, and which document governs if they conflict. A scope gap was always needed but not priced clearly; a true change is something different from what the documents describe. Contract wording usually decides who bears the cost, so a written answer helps settle it.

What are the common ways to price a change order?

Three bases are common: unit rates from a schedule in the contract, a lump sum for work that can be scoped in advance, and time and materials when scope cannot be defined. Time and materials needs controls such as a not-to-exceed figure, agreed hourly rates, daily timesheet sign-off and a clear statement of what markup applies.

Should a change order include the effect on the schedule?

Yes. A change order that states only a price is incomplete, even if the schedule effect is none. It should say whether the work is on the critical path and whether time is added. Without that, a contractor may later claim an extension on top of the price, so confirm that the stated price and time are the full adjustment.