Work Order vs Change Order: What Subcontractors Need to Know

A work order tells you to start specific work under an agreement that already exists. A change order amends that agreement: it changes the scope, the price, the schedule, or all three. The two documents sound alike and often land in the same inbox, but they do different jobs. Treat a work order like a change order, or the reverse, and you can end up doing extra work with no signed paper behind it.

This guide explains the difference in plain terms, shows when each applies on a commercial subcontract, and walks through what to document so you get paid.

TL;DR

• A work order authorizes defined work under a master agreement. It is not a stand-alone contract.
• A change order is a written amendment to the contract. It adjusts scope, contract sum, and contract time.
• Extra work without a signed change order is a payment risk. Get the signature before you proceed whenever the contract allows.
• Proposal requests, directives, and RFIs are not change orders. Cost and time stay open until a change order is fully executed.
• Document labor, materials, and time every day so the change order price holds up.

Table of Contents

• The short answer: authorization versus amendment
• Is a work order the same as a contract?
• When to use a work order and when you need a change order
• Proposal requests, directives, RFIs, and change orders
• What a change order should document
• How to get changed work approved and paid
• Where work orders and change orders go wrong
• Our perspective
• Keep change orders moving with CO Hub
• FAQ
• Sources

The short answer: authorization versus amendment

Think of it this way. A work order answers “what should we start now?” A change order answers “what did we just agree to change about the deal?”

The AIA’s A422–2018 form is a good model of how a work order works. The AIA’s instructions describe it as a work order used with a master agreement between contractor and subcontractor. The master agreement sets the common terms and conditions. The work order supplies the project-specific pieces: the subcontractor’s scope, subcontract time, and subcontract sum. It is not a stand-alone agreement.

A change order sits on the other side of the contract. The University of California facilities manual defines it as a post-award contract modification that may revise, add, or delete requirements and adjust the contract sum or contract time. Caltrans puts it more bluntly: a change order is a legally binding document used to make changes to the contract.

Side-by-side comparison

One caution on vocabulary. “Work order” means different things in different corners of the industry. In facilities and maintenance, it is often a service ticket. In subcontracting, it is more often the release document under a master subcontract. Read the document itself and your contract’s definitions, because the title on the page does not decide its legal effect.

Is a work order the same as a contract?

No. Under a master-agreement structure, the work order depends on the master. A sample subcontractor master agreement illustrates the pattern: an executed work order authorizes the subcontractor to start specified work, identifies scope, schedule, and compensation, and stays subject to the master agreement.

That has a practical consequence. If the master agreement says changes must be in writing and signed, a work order does not wave that rule away. It sits under it.

It also helps to understand where you stand in the chain. A subcontract is a separate contract between the prime contractor and the subcontractor, while the prime contractor stays liable to the owner for the subcontracted work. So when the owner changes something, the change usually reaches you as a change to your subcontract, and the paperwork that flows down to you needs to match the paperwork that flows up.

When to use a work order and when you need a change order

Use this quick test on any request that lands on your desk.

1. Is the work already inside your signed scope and price? Then it is not a change. A work order or release under the master agreement may start it, and no change order is needed.
2. Does the work add to, delete from, or alter your scope, price, or schedule? That is a change order.
3. Is the work outside the contract’s scope altogether? Caltrans cautions that work outside an existing contract’s scope generally should be performed under a separate contract, subject to specified exceptions and approvals. On a private subcontract, read your changes clause to see what counts as a change and what counts as new work.
4. Is someone telling you to proceed before price is agreed? You may be looking at a directive. See the section below.

Examples from the field

• Work order: Your master subcontract covers framing on a multi-building job. The GC releases Building C with a work order stating scope, sum, and duration. Nothing in the contract changed. You were given a defined piece of it.
• Change order: Mid-way through Building C, the owner adds two interior partitions per a revised drawing. Your sum and time need to move. That is a change order.
• Neither yet: A superintendent walks the site and asks you to “just add blocking at the lobby.” It is probably a change, but until it is written and priced, it is a request.

If you want a plain-language walk through of how these requests move through a job, this explanation of how contractor change orders work covers the basics from the contractor’s side.

Proposal requests, directives, RFIs, and change orders

Much of the confusion comes from documents that sit between the first question and the signed change order.

• RFI (request for information): A question about the drawings or specifications. It may lead to a change, but it is not one.
• Proposal request: SMACNA’s Contracts Bulletin explains that an AIA proposal request identifies the proposed change and the parties but is not itself authorization to perform the changed work. You price it. You do not build it on that basis alone.
• Construction change directive: Minnesota State’s overview describes a directive as a written order to proceed before scope, cost, or schedule are agreed, whereas a change order states those adjustments. The same document says payment for directive work cannot be made until the change order is fully executed, after the contractor supplies detailed labor, material, and time-impact information.
• Change order: The executed document. Los Angeles’s Bureau of Engineering says a finalized change order documents the agreed scope, cost, and schedule adjustments and, once fully executed, is a legal and binding amendment to the construction contract.

The lesson is the same at every step: until negotiation ends and signatures are on the page, cost and time remain unfixed. A directive can tell you to move. It does not fix what you will be paid. That is why your records during directive work matter so much.

What a change order should document

A change order that survives an audit or a dispute shows its math. Public owners publish their expectations, and they are a useful benchmark even on private work.

Los Angeles lists the support that belongs with a change order: revised drawings and specifications, invoices, schedule analyses, the contractor’s proposal, the estimate, the negotiation record, and related correspondence, plus the required signatures. The U.S. Army Corps of Engineers says a price breakdown should be detailed enough to analyze labor, material, equipment, subcontracts, overhead, and profit, including work added, deleted, or changed.

At a minimum, make sure yours covers:

• Scope: exactly what is added, deleted, or changed, with drawing and specification references.
• Cost: a breakdown by labor, material, equipment, subcontracts, overhead, and profit.
• Time: how many days the change adds or removes, or a clear statement that it adds none.
• Approval: the signatures the contract requires, dated.

If you want a ready structure, our change order template with six required fields is a good starting point.

How change orders get priced

The University of California identifies four pricing methods: contract unit prices, agreed unit prices, an agreed lump sum supported by a cost proposal, and actual cost plus a contractor fee. Caltrans describes pricing extra work by agreed fixed unit prices or an agreed lump sum, with the change order showing the agreed price.

Which method you land on often depends on how clear the scope is. Well-defined work suits a lump sum. Work that is still being discovered often runs on time and material, which depends entirely on how well you track hours and materials as they happen. We cover that in change order pricing with daily T&M tickets and in our guide to markup on small change orders.

How to get changed work approved and paid

The most expensive mistake in this whole topic is doing the work first and asking for the paper later. SMACNA warns that informal or unwritten changes are risky, and that contractors may have little chance of payment for unauthorized changed work. Its recommended route is to follow the contract’s change-order procedure, submit a written proposal with the reason, plan and specification references, and the price and time effects, and obtain a signed change order before doing the extra work. Do not rely on oral assent.

The Army Corps playbook lays out the same rhythm on federal work: once the change scope is understood, the contractor submits a detailed cost and schedule proposal, followed by negotiation and a signed contract modification. Scope definition, pricing, negotiation, and execution are separate steps, and keeping them separate is what keeps the process reliable.

A workable routine for a subcontractor:

1. Flag it the same day. Tell the GC in writing that a change is occurring, and cite the drawing, RFI, or direction behind it. Our guide on same-hour change order notices shows how.
2. Capture the field facts. Photos, crew hours, materials, and who directed the work. Use a same-day documentation checklist so nothing depends on memory.
3. Submit a priced proposal. Reference the contract clause, break out labor, material, equipment, overhead, and profit, and state the time impact.
4. Get the signature before you proceed. If the schedule forces you to move first, get the directive in writing and keep T&M records for every shift.
5. Track it to approval. The University of California’s sequence is a useful picture of what happens on the other side: project-manager review, funding verification, a representative’s recommendation, contractor acceptance, facility approval, then distribution of the executed change order with backup. Our step-by-step approval process shows where requests usually stall.

Timing matters too. Slow approvals tie up your cash, so it is worth reading how to shorten change order turnaround.

Where work orders and change orders go wrong

A few patterns repeat on subcontract jobs.

• Treating a work order as permission to change scope. A release under the master agreement authorizes the work it describes. If the work grows, the growth needs its own change order.
• Treating a proposal request as a go-ahead. You price it, you submit it, and you wait for the executed document.
• Letting small changes pile up. Ten unsigned extras of an hour or two each add up to real money. Our scope creep control steps are built for this.
• Skipping time. A change that adds days to your schedule but is signed for cost only can leave you exposed on delay. State the time effect on every change order, even when it is zero.
• Losing the paper trail. Approvals sitting in text messages and photos on someone’s phone do not help at closeout.

Our perspective

We built Won2Build because the subcontractors we worked with kept losing money in the gap between “do it now” and “we’ll sort out the paperwork later.” The work order and the change order are not the problem. The gap between the field and the office is.

When a foreman gets a verbal request, the real question is whether the hours, materials, and photos from that day will reach the person who writes the change order. If they do not, the price gets reconstructed from memory a month later, and memory is not a very strong exhibit.

That is why our suite is designed around one login and one flow of data. Time Budge captures labor against the job, CO Hub turns that field record into a priced change order and T&M ticket, and Bid Track and Takeoff keep estimating tied to the same project. We want a change to be documented once, in the field, and carried through to approval without re-keying it.

Our advice: whatever tools you use, make the signed change order the finish line for every extra, and make same-day documentation the starting line.

Jen Reese

Keep change orders moving with CO Hub

If your change orders live in spreadsheets and email threads, CO Hub is built to manage change orders and T&M tickets in one place, with field data syncing to the office. It costs $59 per month per company, and the active field worker fee is $2 per month per active field worker. Current plans are on our pricing page.

If you also need labor tracking, estimating, or plan takeoff, the Won2Build Hub puts the apps behind a single sign-on, so labor hours recorded in the field are available when you price the change.

FAQ

Is a work order the same as a change order?

No. A work order authorizes specific work to begin, usually under a master agreement. A change order is a written amendment that adjusts the contract’s scope, sum, or time. A work order can sometimes carry the original scope and price, while a change order changes them after the fact.

Can I start extra work before the change order is signed?

The safest answer is no. SMACNA warns that contractors may have little chance of payment for unauthorized changed work. If the schedule forces you to move, get a written directive, keep detailed daily records, and follow your contract’s notice requirements. Ask your attorney about your specific contract.

Does a work order change my subcontract price?

Only if the contract says so. Under a master-agreement structure, the work order supplies the project-specific scope, time, and sum for that release, and it stays subject to the master agreement. A change to an already-agreed price should come through a change order.

What is the difference between a change order and a construction change directive?

A directive is a written order to proceed before scope, cost, or schedule are agreed. A change order states the agreed adjustments. Payment for directive work generally waits until the change order is fully executed, so keep labor, material, and time records while you work.

Sources

• Caltrans, Section 5-0 Conduct of the Work and Section 5-3 Changes
• University of California Facilities Manual, Volume 5, Chapter 13: Contract Modifications
• AIA Contracts, Instructions for A422–2018 Work Order
• Virginia Tech, Purchase Order and Subcontract Agreements
• Subcontractor master agreement example, Law Insider
• Los Angeles Bureau of Engineering, 20.4 Finalizing Change Orders
• U.S. Army Corps of Engineers, Contract Changes Playbook
• SMACNA Contracts Bulletin #98, Change Orders and Extra Work
• Minnesota State, Construction Change Overview
• Contractor Change Orders: How They Work and How to Handle Them

Recommended

• Change Order Documentation: Subcontractors’ Same Day Field Checklist
• Subcontractors: Protect Margins With 48 Hour Change Order Management
• Notice of Change: What Subcontractors Must Send and When
• Subcontractor Playbook to Get Paid for Unsigned Change Orders