Concurrent delay is where most claims go quiet. Not because the delay is unclear, but because no two parties define concurrency the same way, and the definition is what decides whether the owner collects liquidated damages or the contractor collects a time extension with no money attached.

The vagueness is not an accident. Concurrency is the most useful word in a contractor’s vocabulary, because if a delay is concurrent, the contractor usually keeps its time extension and the owner usually loses its liquidated damages. So the term gets stretched to cover situations that are not concurrent at all. Here is the version without the stretch.

What concurrent delay actually means

Concurrent delay is two or more delays running in the same period, where at least one is the owner’s responsibility and at least one is the contractor’s, and each is independently capable of delaying the project completion date.

Three conditions have to hold. The delays overlap in time. They come from opposite sides of the contract. And both sit on the critical path, or both would extend completion on their own. Strip any one of those away and you do not have concurrency, you have a single delay with a story built around it.

The definition nobody agrees on

The first fight is almost always about what “same period” means.

True concurrency is when the two delays literally overlap in time. Both are actively delaying the project on the same days. Functional or sequential concurrency is looser. The two delays fall inside the same analysis window but do not happen on the same days. One analyst will call sequential delays in a single monthly window concurrent. Another will insist concurrency requires literal overlap. Both can cite support.

That gap is not academic. It decides cases. Whether a contractor’s two-week slip and an owner’s two-week slip in the same month count as concurrent depends entirely on which definition the forum adopts, and the standards do not agree.

Why concurrency usually cancels the money

When delay is found to be concurrent, the typical outcome across most forums looks the same. The contractor gets an extension of time, because part of the delay was the owner’s. The contractor does not get prolongation costs, because part of the delay was its own. And the owner does not get liquidated damages for that period, because it was contributing to the delay too.

Time gets extended. Money washes out on both sides. That is why concurrency is a shield for the contractor against liquidated damages and a sword for claiming time, often in the same breath.

Pacing is not concurrency

Here is the distinction owners miss most. Pacing is when a contractor deliberately slows down because an owner-caused delay is already driving the finish. The reasoning is rational. If the building cannot be enclosed until the owner resolves a design issue, there is no point running the interior crews at full speed. So the contractor paces its work to the real constraint.

Pacing is a defense, not culpable delay, when it is a genuine response to an owner delay that was already critical and the contractor documents the decision. Owners get this backward. They see the contractor slow down, log it as contractor delay, and walk into a pacing defense they did not see coming. Contractors abuse it from the other direction, relabeling their own culpable slowdown as pacing after the fact. The difference is in the contemporaneous record. A real pacing decision leaves a trail. A retroactive one does not.

The standards do not line up

There is no single national test for concurrency in the United States. AACE International addresses it in Recommended Practice 29R-03. The Society of Construction Law protocol takes its own position. Courts and boards split between apportioning concurrent delay and applying a but-for analysis, and they split again on whether literal overlap is required. None of this is settled, and a piece like this is not the place to pretend it is. What matters for an owner is knowing the ground is contested before a contractor plants a flag on it.

Concurrency is decided by your critical path

Every concurrency argument resolves to one question. What was actually critical during the window. You cannot establish concurrency, and more to the point you cannot rebut a contractor’s concurrency claim, without knowing which activities were driving the finish day by day. That requires valid contemporaneous schedule updates.

If the updates were never properly statused, the critical path is unknowable after the fact, and an unknowable critical path is exactly the condition under which a contractor’s concurrency claim cannot be challenged. The owner who let schedule discipline slide during construction has already lost the concurrency argument. They just do not find out until the claim lands.

What this means for owners before a claim

The concurrency fight is won with records, and the records are made during construction.

• Define concurrency and float in the contract. Do not leave the most contested term in delay analysis to whichever expert the dispute hands you.
• Keep the schedule updates valid. A defensible critical path is the only thing that lets you separate a real concurrent delay from a manufactured one.
• Document pacing in real time. If the contractor is pacing, get the reason on paper when it happens. If you are the one alleging contractor delay, confirm it was not a response to your own slip first.

Frequently asked questions

What is concurrent delay in construction? Two or more delays in the same period, at least one caused by the owner and at least one by the contractor, where each independently affects the completion date. Both must sit on the critical path.

Does a contractor get paid for concurrent delay? Usually not. The common outcome is a time extension with no prolongation costs. The owner, in turn, usually cannot recover liquidated damages for the concurrent period.

What is the difference between concurrent delay and pacing? Concurrent delay is two independent delays from both sides. Pacing is the contractor deliberately slowing its work in response to an owner delay that is already driving the finish. Pacing can be a legitimate defense; concurrent delay is a shared-fault finding.

Who has the burden of proving concurrency? The party relying on it, typically the contractor using concurrency to defeat liquidated damages. The proof lives in the contemporaneous schedule updates, which is why their quality decides the argument.