Key Takeaways
- The schedule is a contract document in practice. When a project falls behind, the schedule — not memory — becomes the primary evidence of who delayed what.
- CPM identifies the activities that actually drive the finish date. The critical path is the longest chain of dependent work; a one-day delay there moves completion by a day.
- The baseline is the yardstick. Without an accepted, preserved baseline schedule, there is no reliable way to measure delay — and disputes get expensive fast.
- Float is scheduling room, and it disappears quietly. Understanding total float, free float, and who 'owns' it is central to nearly every delay claim I review.
- Owners can require all of this before mobilization. A reviewed baseline, update cadence, and float reporting are pre-construction deliverables, not construction-phase afterthoughts.
In my forensic practice, I am usually brought in after something has gone wrong — a leaking envelope, a failed assembly, a project that finished a year late with everyone blaming everyone else. And in delay
Page 1
disputes, the first document I ask for is not the contract. It is the baseline schedule and the monthly updates that followed it. Too often, that request comes back incomplete. Work started before a schedule was accepted. Updates were skipped, or the baseline was overwritten so many times that no original plan survives. At that point, reconstructing what happened — and who is responsible — becomes slow, contested, and costly for every party involved. This article explains, in plain language, how construction schedules and the Critical Path Method (CPM) work, what a baseline schedule actually is, why float matters more than most owners realize, and what to require before the first crew mobilizes.
What Is the Critical Path Method (CPM)?
The Critical Path Method is the standard scheduling technique used on most commercial and many larger residential projects. The idea is straightforward: break the project into discrete activities, assign each a duration, and link them with logic ties — relationships that define what must finish before something else can start. Concrete cures before framing bears on it; the roof dries in before drywall hangs. Once the network is built, the scheduling software calculates every possible path from start to finish. The critical path is the longest chain of dependent activities. It determines the earliest possible completion date. Activities on that path have no room to slip: delay one of them a day, and — absent recovery measures — the project finishes a day later.
Page 2
Everything not on the critical path has some amount of float, which we will come back to. Two practical points follow from this structure. First, not all delays are equal — a two-week slip on a non-critical activity may cost nothing, while a two-day slip on the critical path moves the completion date. Second, the critical path is not static. As work progresses and logic changes, the path can shift to a different chain of activities. That is why a single schedule printed at the start of the job is not enough; the network has to be updated and re-calculated throughout construction.
What Is a Baseline Schedule, and Why Does It Matter So Much?
The baseline schedule is the approved plan of record: the contractor's CPM schedule, reviewed and accepted before (or very early in) construction, then preserved unchanged for the life of the project. Monthly updates are compared against the baseline — they never overwrite it.
From a forensic standpoint, the baseline serves one indispensable purpose: it is the yardstick. Delay analysis — whatever the method — works by comparing what was planned against what actually happened, and by testing how specific events shifted the critical path. If no accepted baseline exists, or if it was quietly revised as the job slipped, that comparison becomes a reconstruction exercise built on fragments: daily reports, pay applications, inspection records, photographs. It can be done, but it is slower, more contested, and far more expensive than simply preserving the schedule of record from day one. A baseline also protects the contractor. A realistic, accepted baseline that documents owner-controlled milestones — permit issuance, owner-furnished equipment, design decisions — is often the contractor's
Page 3
best evidence when owner-side delays occur. A good baseline is not a weapon for one side; it is shared protection.
What Is Float, and Who Owns It?
- Total float is how far an activity can slip before it delays the project completion date.
- Free float is how far it can slip before it affects the next activity in line.
Critical-path activities, by definition, have zero total float. Everything else carries some cushion — and that cushion gets consumed quietly. A submittal reviewed late here, a crew pulled to another job there, and an activity that once had three weeks of float suddenly has none. Nobody sent a delay notice, because no single event moved the finish date. But the project's shock absorbers are gone, and the next problem — weather, a failed inspection, a supply issue — lands directly on the completion date. Then comes the question I see argued in claim after claim: who owned that float? Many contracts state that float belongs to the project — available to whichever party needs it first, owner or contractor. Others are silent, which invites dispute. The practical takeaway for pre-construction is simple: address float ownership in the contract, and require float reporting in the monthly updates so its consumption is visible while there is still time to respond, not discovered afterward in litigation.
How Do Schedule Problems Become Schedule Disputes?
Page 4
Across the delay and defect matters I have reviewed, schedule disputes rarely trace to one dramatic
event. They follow a recognizable pathway of small, individually forgivable lapses:
The final step in that pathway deserves emphasis, because it connects scheduling to my core work in
building envelope forensics: schedule compression is a quality event, not just a time event. When float is gone and the completion date is fixed, trades get stacked, work goes in out of sequence, and moisturesensitive assemblies get closed in before they are ready. Some of the envelope failures I investigate began not as bad workmanship in isolation, but as reasonable people rushing under an impossible recovery schedule. Protecting the schedule protects the building.
A Composite Example: The Baseline That Never Existed
Illustrative Composite — Not a Specific Project The following is a composite drawn from patterns seen across multiple engagements. It does not describe any single project, client, or contractor.
A mid-rise mixed-use project broke ground while the contractor's schedule was still 'in review.' It
was never formally accepted. Monthly updates were issued, but each one was saved over the last, and logic ties were deleted whenever the software flagged out-of-sequence work. Fourteen months in, the project was materially behind, the owner was assessing liquidated damages, and the contractor was claiming owner-caused delay tied to late design decisions. Both sides may well have had legitimate positions. But with no preserved baseline and no clean update history, neither could prove them efficiently. The delay analysis had to be reconstructed from daily reports, inspection logs, and photo records — months of expert work on both sides addressing questions a preserved schedule of record would have answered in days. The scheduling
Page 5
discipline that was skipped to save time before construction was repaid many times over in dispute costs after it.
What Should Owners and Their Teams Require Before Construction Starts?
Every item below is a pre-construction deliverable. None requires the owner to become a scheduler — only to ask for the right things and have someone qualified review them. Requirement
Why It Matters
CPM baseline schedule submitted and formally
accepted before mobilization (or within the contract-specified window)
Establishes the yardstick for all future delay measurement
— and forces realistic planning before crews arrive
Schedule specification in the contract (level of
detail, software, update cadence, float ownership)
Removes ambiguity about what the schedule must contain
and who may use the float
Monthly updates compared against the
preserved baseline, with a narrative of changes
Creates a contemporaneous record; changes are visible
when they happen, not reconstructed later
Float and critical-path reporting in every update
Makes quiet float consumption visible while recovery is still
possible
Procurement and submittal activities included
in the network
Long-lead materials and review cycles cause many 'invisible'
delays; putting them in the logic exposes them
Weather planning and realistic durations, not
placeholder numbers
A baseline nobody believes in will be ignored — and an
ignored schedule protects no one
Pre-Construction Schedule Review Checklist
☐ Baseline schedule submitted, reviewed, and formally accepted in writing ☐ Original baseline archived and preserved — updates never overwrite it ☐ Contract addresses float ownership and update frequency
☐ Critical path is identified and passes a common-sense reasonableness check
☐ Permits, submittals, and long-lead procurement appear as activities in the network
☐ Owner-controlled milestones (decisions, furnished items, access) are shown and dated ☐ Update format includes a change narrative and float/critical-path report
Page 6
☐ Someone on the owner's side is designated to review each update when it arrives
Frequently Asked Questions
Do small projects really need a CPM schedule? The formality should scale with the project, but the principles do not change. Even a custom home benefits from a written schedule with logic — what must finish before what starts — and a preserved original to measure against. On small projects that may be a well-built bar chart rather than full CPM software; the discipline matters more than the tool.
What is the difference between a baseline schedule and a look-ahead schedule?
The baseline is the approved plan of record for the whole project, preserved unchanged. A look-ahead (often two or three weeks) is a short-term working tool for coordinating crews. Look-aheads are valuable, but they are not a substitute for a maintained CPM schedule — they cannot show the critical path or measure delay.
Who typically owns float?
It depends on the contract. Many contracts assign float to the project — first come, first served — while others are silent, which is where disputes start. The important thing is to decide the question in the contract during pre-construction rather than argue it during a claim.
Can the critical path change during construction?
Yes, and it frequently does. As activities finish early or late and logic is revised, a different chain of work can become the longest path. This is exactly why regular schedule updates matter: the path that controls the finish date in month ten may not be the one that controlled it at the baseline.
What happens in a delay dispute when there is no reliable baseline?
The analysis does not become impossible — it becomes a reconstruction. Experts rebuild the as-planned and as-built picture from daily reports, pay applications, inspection records, correspondence, and photographs. It can be done credibly, but it takes substantially more time and cost on all sides, and it leaves more room for competing interpretations.
Join the Conversation
Have you seen a project where the schedule quietly fell apart long before anyone sent a delay notice? What early warning sign do you wish someone had acted on? Share your experience in the comments.
Page 7
Page 8