Change Orders and Contract Modifications
Federal and District of Columbia public construction contracts generate change orders at a rate that routinely adds 10–15% to original contract values, according to GAO oversight findings on federal construction programs. For contractors working in the District — whether on federal facilities, DC government buildings, or infrastructure projects — understanding the mechanics of contract modifications is not optional. A missed deadline for submitting a Request for Equitable Adjustment (REA) or a failure to issue proper written notice can extinguish a valid claim worth tens of thousands of dollars.
What Constitutes a Contract Modification
Under FAR Part 43, a contract modification is any written change to the terms of a contract. Federal construction contracts distinguish between two primary types:
- Bilateral modifications (Supplemental Agreements) — signed by both the contractor and the Contracting Officer (CO). These cover negotiated scope changes, price adjustments, and settlement of claims.
- Unilateral modifications — issued by the CO alone. Administrative changes and Change Orders issued under the Changes clause fall here.
DC public contracts mirror this structure under DCMR Title 27, which governs the Office of Contracting and Procurement. Under DC procurement rules, modifications to construction contracts above the simplified acquisition threshold must receive written approval from the Agency Chief Contracting Officer before work proceeds.
The Changes Clause: Core Authority
The FAR 52.243-1 Changes clause is the engine behind federal change orders. It authorizes the CO to order changes within the general scope of the contract covering:
- Drawings, designs, or specifications
- Method or manner of performance
- Government-furnished facilities, equipment, or materials
- Acceleration of delivery or performance schedule
The clause obligates the contractor to continue performance while a change is pending. This is the critical trap: stopping work pending resolution of a change order dispute constitutes a potential breach. Contractors must proceed and document, not stop and fight.
Constructive Changes
A constructive change occurs when a contractor performs work beyond the contract requirements due to government action — or inaction — without a formal written change order being issued. Common triggers include:
- Defective or ambiguous specifications that force a more expensive construction method
- Overinspection or rejection of conforming work
- Acceleration orders that are verbal rather than written
- Differing site conditions discovered after contract award
The ABA Section of Public Contract Law identifies constructive changes as one of the 3 most litigated areas in federal construction contract disputes. Contractors must issue written notice of a constructive change claim promptly — federal contracts typically require notice within 20 days of the event giving rise to the claim under FAR 52.243-1.
Differing Site Conditions
Under FAR 43 and the standard Differing Site Conditions clause (FAR 52.236-2), contractors encountering concealed or unknown physical conditions materially different from what the contract indicated must stop and notify the CO before disturbing the condition. Two categories apply:
- Type I — Conditions materially different from those indicated in the contract documents
- Type II — Conditions unusual in nature, differing materially from conditions ordinarily encountered in work of the contract type
DC construction sites — particularly those involving underground utility conflicts in historic areas like Georgetown or Capitol Hill — regularly produce Type I differing site conditions claims. The DC Water and Sewer Authority's aging infrastructure creates documented conflicts with drawings on file at the DC Office of Contracting and Procurement.
Equitable Adjustments: Calculating What Is Owed
An equitable adjustment has three components (according to the National Institute of Building Sciences and established federal procurement precedent):
- Direct costs — labor, materials, equipment directly attributable to the change
- Indirect costs — overhead, supervision, extended general conditions
- Profit — reasonable profit on the adjusted work, typically calculated at 10% on cost under federal practice
Documentation is everything. A contractor claiming extended general conditions on a USACE project must produce contemporaneous daily reports, certified payrolls, equipment rental logs, and superintendent time records. The U.S. Army Corps of Engineers requires that REAs include a detailed cost breakdown at the line-item level; lump-sum submissions are routinely rejected or heavily discounted.
Notice Requirements and Deadlines
Missing notice deadlines kills claims. Key timelines on DC and federal projects:
| Contract Type | Notice Deadline | Claim Submission Deadline |
|---|---|---|
| Federal (FAR 52.243-1) | 20 days from change event | Before final payment |
| DC Government (DCMR Title 27) | Written notice at time of change | Within 30 days of CO final decision |
| USACE Projects | As specified in individual contract | Typically 6 months from REA submission |
The 20-day federal notice clock runs from the date the contractor knew — or should have known — about the changed condition. Lack of actual knowledge is not a defense if the condition was observable.
OSHA-Triggered Modifications
OSHA construction standards (29 CFR 1926) can independently generate legitimate change order claims. When a CO or inspector mandates a safety measure not addressed in the original contract drawings — shoring requirements in an excavation exceeding 5 feet, or confined space procedures triggered by an unforeseen utility vault — the contractor has grounds to seek a modification. The key is documenting the regulatory mandate in writing at the time it is imposed, not retroactively.
Practical Documentation Protocol
For every change — directed, constructive, or differing-site-conditions:
- Issue written notice to the CO within the contract deadline
- Keep separate cost codes for changed work from day one
- Record daily: crew hours, equipment hours, material deliveries, subcontractor presence
- Photograph existing conditions before, during, and after
- Capture all verbal directions in a written follow-up email within 24 hours confirming what was directed and by whom
The DC Office of Contracting and Procurement processes change orders through its Oracle-based contract management system; electronic submittals with supporting documentation attachments are the standard format for DC agency projects.
References
- FAR Part 43 — Contract Modifications
- FAR 52.243-1 — Changes Clause
- U.S. Army Corps of Engineers — Business With Us / Small Business
- GAO — Contracting Topics
- DC Office of Contracting and Procurement
- DCMR Title 27 — Contracts and Procurement
- National Institute of Building Sciences
- ABA Section of Public Contract Law
- OSHA Construction Standards
The law belongs to the people. Georgia v. Public.Resource.Org, 590 U.S. (2020)