Construction Change Orders: How to Price, Document, and Get Them Signed
Every job changes. What separates profitable contractors from busy ones is whether the change gets documented before the work happens. Here is the process, the pricing, and the wording.
The short version
- A change order is a written amendment signed by both parties before the changed work begins. Anything less is an invoice you will have to argue for.
- Price the full cost of the change, not just the extra labour — disruption, resequencing, remobilisation, and schedule impact are real costs.
- Always state the schedule impact, even when it is zero. Silence on timing is how a change becomes the reason you are "late".
- The clause that makes it work is the one saying you are not obligated to perform changed work until the change order is signed.
On this page
- What triggers a change order
- Client-requested additions
- Concealed or unforeseen conditions
- Design or specification changes
- Regulatory and inspection-driven changes
- What a change order must contain
- How to price a change order
- Time-and-materials change orders
- How to raise one without losing the client
- 1. Raise it immediately
- 2. Show, do not tell
- 3. Present options where they exist
- The contract clause that makes it enforceable
- A change order form you can copy
- Common change order mistakes
A change order is a written amendment to a construction contract that modifies the scope, price, or schedule, signed by both parties before the changed work starts. It is not an invoice, not an email, and not a note in the job diary. It is a contract document, and treating it as one is the difference between billing for extra work and absorbing it.
Nearly every job changes. The client adds an outlet, the wall opens up and the framing behind it is rotten, the specified fixture is discontinued. None of that is a problem. The problem is doing the work first and raising the money afterwards.
What triggers a change order
Four categories, and they behave differently in conversation.
Client-requested additions
The easiest to price and the easiest to let slide. "While you're in there, could you also…" is a change order, however small it sounds. The danger is not the individual request — it is that saying yes to three of them establishes that requests are free.
Concealed or unforeseen conditions
You open a wall and find knob-and-tube wiring, water damage, or a structural member that is not where the drawings say. This is not your fault and not the client's, which makes it the most emotionally difficult conversation of the four.
Handle it by documenting immediately: photograph the condition before touching anything, stop work in that area, and raise the change order the same day.
Design or specification changes
The architect revises a detail, the client changes a finish, a specified product is discontinued. Watch for the ripple effects — a fixture change can alter rough-in locations, which alters work you have already completed.
Regulatory and inspection-driven changes
An inspector requires work beyond the contract scope, or a code interpretation differs from what was assumed. Note the distinction: bringing your own work up to code is your obligation; remediating pre-existing violations you did not create is a change.
What a change order must contain
Required elements
- A sequential change order number (CO-001, CO-002) and the date
- Reference to the original contract by name and date
- A description of the change, specific enough to be unambiguous a year later
- The reason for the change — client request, concealed condition, design revision
- The price adjustment, broken down into labour, materials, equipment, and markup
- The revised contract total, showing original price plus all changes to date
- The schedule impact in days, including when it is zero
- The revised completion date
- Any change to payment terms, if the change is large enough to warrant its own milestone
- Signature and date blocks for both parties
How to price a change order
The common mistake is pricing only the visible work. An extra outlet is not "twenty minutes and a receptacle" — it is a trip back, a change in sequence, a re-inspection, and a delay to everything downstream.
| Cost component | What to include |
|---|---|
| Direct labour | Hours at your rate, including the crew members actually pulled onto it |
| Materials | At cost plus your standard markup, including waste and delivery |
| Equipment | Additional rental, or additional days on existing rental |
| Rework | Undoing or modifying work already completed |
| Disruption | Lost productivity from resequencing, stop-start working, crew standing by |
| Remobilisation | A return trip if the change cannot be done in the current visit |
| Extended overhead | Site costs that continue for every extra day on the job |
| Overhead and profit | Your standard markup — a change order is not a favour |
Small change orders should carry a minimum charge. A $40 part that costs you a separate trip is not a $40 change order. Set a floor — many contractors use a minimum equal to one hour of labour plus materials — and state it in the original contract so it is not a surprise.
Time-and-materials change orders
When the extent is genuinely unknowable — opening a wall of unknown condition — a T&M change order is honest and defensible. Make it safe for both sides:
- State the hourly rate and material markup explicitly
- Include a not-to-exceed cap, with a requirement to seek approval before passing it
- Commit to daily reporting of hours and materials
- Define what happens if the cap is reached mid-task
How to raise one without losing the client
The conversation, not the paperwork, is where change orders go wrong. Three rules cover most of it.
1. Raise it immediately
The moment you know. A change surfaced the same day is a fact of the job. The same change surfaced in the final invoice is an accusation of overcharging.
2. Show, do not tell
For concealed conditions, photograph it and show the client. Someone looking at a picture of rotten framing is not arguing about whether replacement was necessary. Text the photo before you write the change order.
3. Present options where they exist
A change order with a single price feels like an ultimatum. Two or three options feel like advice.
"Hi Marcus — opened up the wall behind the panel this morning and the framing has water damage, photos attached. It needs addressing before I can mount the new panel safely. Three options: 1. Replace the affected studs and the section of sheathing — $840, adds one day. 2. Sister the damaged studs and treat the sheathing — $410, adds half a day. Sound, but I would want it inspected again in a couple of years. 3. I stop here and you bring in a carpenter. Happy to work around whatever they schedule, though it will likely add three or four days once we resequence. My recommendation is option 1 — the sheathing is soft enough that I would not want to hide it. Let me know and I will send the change order to sign."
Note what that message does: it leads with evidence, offers real choices including the option not to use you, gives a recommendation with a reason, and ends with a clear next step. It does not apologise, and it does not hedge.
The contract clause that makes it enforceable
None of this holds up unless your original contract requires it. Put this in every agreement:
Changes. No change to the scope of work, Contract Price, or schedule shall be effective unless documented in a written change order signed by both parties before the changed work commences. Verbal instructions, site directions, and email requests do not constitute change orders and do not modify this Agreement. Contractor is under no obligation to perform changed work until a change order has been signed. Change orders shall be priced at Contractor's standard rates, with a minimum charge of $[amount] per change order. Each change order shall state its impact on the completion date. Where a change order is signed without a stated time impact, the schedule shall be extended by a reasonable period attributable to the change.
Three sentences are doing heavy lifting there. "Under no obligation to perform" makes signing the client's problem. The minimum charge stops trivial requests being free. The default schedule extension protects you if a change order goes out without a time figure.
A change order form you can copy
CHANGE ORDER No. CO-003 Date: 14 July 2026 Original Contract: Electrical Services Agreement dated 2 June 2026 Project: 44 Henderson Street — panel upgrade and rewire Contractor: [Legal entity, licence no.] Client: [Full legal name] Description of change Replace three (3) water-damaged wall studs and 4' x 8' section of sheathing at the north wall behind the electrical panel, to permit safe mounting of the new 200-amp panel. Reason for change Concealed condition discovered on removal of existing panel, 14 July. Condition not visible at time of estimate. Photographs attached. Price adjustment Labour: 8 hrs @ $85/hr — $680 Materials: lumber, sheathing, fasteners, treatment — $124 Overhead and profit (15%) — $121 Total this change order: +$925 Original Contract Price: $8,400 Previous change orders (CO-001, CO-002): +$310 Revised Contract Price: $9,635 Schedule impact +1 working day. Revised completion date: 24 July 2026. Payment Added to the Substantial Completion milestone. All other terms of the original Contract remain unchanged. Contractor: ______________________ Date: __________ Client: ______________________ Date: __________
Common change order mistakes
| Mistake | What it costs you |
|---|---|
| Doing the work first, papering it later | You lose all leverage — the work is already delivered |
| Accepting a verbal go-ahead | The clause becomes waivable, and the record is a memory |
| Pricing only the direct labour | Disruption and remobilisation come out of your margin |
| Leaving schedule impact blank | You become responsible for a delay you did not cause |
| Bundling several changes into one | One objection blocks approval of everything |
| Absorbing small changes to be agreeable | Establishes that requests are free, and they multiply |
| No sequential numbering | Nobody can reconcile the final total against the original |
The last row is more consequential than it looks. When the final invoice does not tie back cleanly through numbered change orders to the original contract price, clients assume something is wrong even when nothing is.
Frequently asked questions
Can a client refuse to sign a change order?
Yes — and that is the correct outcome of the process working. If they refuse, you do not perform the changed work. Confirm in writing that the item is outside the contract scope and will not proceed without a signed change order, then carry on with the original scope. Performing the work anyway and billing later is how contractors end up unpaid.
Do change orders need to be signed, or is email enough?
A signature is far stronger, and most contracts require one. An email reply saying "approved, go ahead" in response to a fully priced change order is real evidence and better than nothing — but a signed document removes the argument about whether the client understood the price and the schedule impact.
How much can I mark up a change order?
Apply your standard overhead and profit — typically 10–20% on top of direct costs. Some contracts cap change order markup, and public work often prescribes it, so check the original agreement. Charging a higher markup on changes than on base work is not illegal, but it damages trust when the client notices.
What if the change order makes the job unprofitable?
That usually means the change is being priced too narrowly. Include disruption, resequencing, remobilisation, and extended overhead — they are real costs of the change, not overheads you should absorb. If the honest full price is unacceptable to the client, the options are a reduced scope elsewhere or not doing the change.
Do small changes really need a change order?
Yes, and they are the ones that matter most for the habit. A written-change-order requirement can be waived by a course of dealing where you routinely do verbal extras. Documenting the $40 items is what keeps the clause available when a $4,000 item appears. Set a minimum charge so small change orders are still worth processing.
Who pays for changes required by an inspector?
It depends on the cause. Correcting your own work to meet code is your obligation and not a change. Remediating pre-existing violations you did not create, or work required by a code interpretation that differs from the documented basis of your estimate, is a change. This is another reason to state your pricing assumptions in the original contract.