A change order in construction is a formal, signed document that modifies the original contract. It adds, removes, or changes the scope of work and adjusts the contract price, the schedule, or both to match.
Until a change is authorized as the contract requires, the added or removed work may fall outside what the parties formally agreed to. That is why disputes over unpaid or unapproved work often trace back to a change that was never documented and approved.
What triggers a change order?
A change order starts with a change event: a drawing revision, an accepted RFI response, a differing site condition, an owner-requested scope change, or a code requirement discovered mid-project. The change event is the moment something changes. The change order is the contract document that follows, usually after the team has evaluated the impact, priced it, and routed it for approval.
The gap between when a change happens and when it is formally captured is where much of the risk sits. An unrecognized change event does not disappear. It can surface later as unbilled work, a dispute over who owns the cost, or a line item absorbed into contingency.
How does a change order differ from a change event, an RFI, and a bulletin?
These terms describe different parts of the change-management process:
- Bulletin: The architect's formal update to the drawings or specifications, often issued to resolve a design gap or incorporate an owner decision.
- RFI: A contractor's formal question to the design team when a drawing or specification is unclear. Most RFIs do not change the contract, but a response that reveals or adds scope can lead to a change event.
- Change event: An occurrence with potential cost, schedule, or scope impact that needs to be evaluated and documented.
- Change order: The final signed instrument that modifies the contract after the impact has been priced and approved.
In practice, one bulletin can touch dozens of sheets across several trades. Determining which revisions are already covered by the contract and which represent added or deleted scope is the real work behind a change order.
Who has to approve a change order?
A change order needs approval from the parties with contractual authority over scope, price, and time. That typically means the owner or owner's representative and the contractor. The architect or engineer may also certify or approve the change when the agreement assigns them that role.
On the general contractor's side, a project manager usually assembles the change documentation, gathers subcontractor pricing, evaluates schedule effects, and routes the package through internal review before sending it to the owner. Standard-form agreements, including AIA and ConsensusDocs contracts, define the required notices, signatures, and approval sequence. The governing contract—not a general industry custom—controls the process for a specific project.
What should a construction change order include?
A complete change order should clearly identify:
- The contract and project it modifies.
- The source of the change, such as a bulletin, RFI response, owner request, or field condition.
- The added, deleted, or revised scope of work.
- The contract-price adjustment, including subcontractor, labor, material, equipment, markup, credit, and allowance details as applicable.
- The number of calendar days added to or removed from the contract time, or an explicit statement that time is unchanged.
- Supporting drawings, specifications, estimates, and schedule analysis.
- The required approvals, signatures, and effective date.
Clear scope and traceable backup matter as much as the final price. If the document does not connect the cost and schedule adjustment to the source documents, teams may have to reconstruct that reasoning months later.
What happens if a change order is not caught in time?
A missed change order does not only affect the cost of one item. It can consume the contingency intended to absorb other project risks. A missed trade on a multi-discipline change can grow from a small unpriced item into a significant cost once labor, material, supervision, schedule, and downstream rework are included.
The timing risk is also contractual. Many construction contracts require written notice within a defined period after the event giving rise to a claim. AIA A201-2017, for example, generally requires claims to be initiated within 21 days under Section 15.1.3, subject to the agreement's terms and applicable law. Missing a contractual notice deadline may limit or waive recovery. Teams should follow the notice and authorization provisions in the executed contract rather than relying on a standard rule of thumb.
How long does it take to process a change order?
There is no universal processing time because contract terms, project size, and change complexity vary. The sequence is consistent: identify the event, trace the affected drawings, specifications, RFIs, trades, and schedule activities, price the impact, negotiate it, and route it for approval.
On a complex multi-trade change, tracing the impact by hand can take days before pricing or approval begins. One illustrative example follows a bulletin that revised 135 sheets across six disciplines. Identifying the affected scope, checking it against the specifications and RFI log, and pricing it at roughly $205,000 took three days of manual tracing before the team could draft the potential change order.
How is Trunk Tools connecting change orders to the rest of the project?
Trunk Tools is building TrunkChange, an agent planned to launch in Q4 2026. When a bulletin or RFI response lands, it uses the revision history already built by TrunkReview and TrunkRFI to trace the affected sheets and trades.
TrunkChange reports potential cost, schedule, and scope impact by discipline, then drafts the change event and a potential change order with a rough-order-of-magnitude estimate for a person to review. The goal is not to remove the judgment or contractual review behind a change order. It is to reduce the manual tracing required before the project team can make that judgment.
Frequently asked questions
What is a change order in construction? A change order is a formal, signed document that modifies a construction contract's scope, price, schedule, or a combination of the three after a change event occurs.
What is the difference between a change order and a change event? A change event is an occurrence with potential scope, cost, or schedule impact, such as a bulletin, RFI response, or differing site condition. A change order is the signed contract amendment created after that impact is priced and approved.
Who signs a construction change order? The parties with contractual authority sign the change order, typically the owner or owner's representative and the contractor. The architect or engineer may also certify or approve it when the contract requires.
What happens if work starts before a change order is signed? Starting changed work without the written authorization required by the contract can put payment and schedule relief at risk because the parties have not formally agreed to the added scope, price, or time.
Does every RFI lead to a change order? No. Most RFIs clarify the contract documents without changing the contract. An RFI may lead to a change order when its response adds, removes, or changes scope with a cost or schedule impact.
By the Trunk Tools team. Published September 23, 2026.
Sources: Trunk Tools, System of action vs. system of record in construction; AIA A201-2017, General Conditions of the Contract for Construction, Section 15.1.3; AIA and ConsensusDocs standard contract forms.