Be Careful How You Use the Word Float

Problem: Float Can Look Like Spare Time

A schedule showing a week of “float” before handover invites an obvious question. “If you don’t need that week, why can’t you finish a week earlier?” That’s a reasonable question. The problem is that the label may not explain what the week actually represents.

Perhaps you need to review commissioning results, finish the handover documents and obtain client acceptance. Perhaps you have allowed time for possible retesting if equipment fails its first performance test. Or perhaps an activity really can move without affecting the project finish date.

These are different situations. Calling all of them float creates confusion and can lead to necessary work or sensible allowances being removed.

Tender teams can face the same pressure to remove allowances to offer a more attractive completion date. Once the time is cut, the work and risks may still be there. Your team could end up rushing the checks, working overtime or missing the revised completion date.

Float Has a Specific Meaning

In scheduling, float describes how much an activity can move within the schedule. Two common types are:

• Total float: How long an activity can be delayed without delaying the project finish or breaching a relevant finish constraint.
• Free float: How long an activity can be delayed without delaying the earliest start of a following activity.

PMI explains this distinction in its article on using float in project schedules.

Float is calculated from the schedule’s durations, links, calendars and constraints. It is not simply a task you add called “spare time”. An activity having five days of total float also does not mean you can finish the whole project five days earlier.

Contingency is different. It is an allowance for uncertainty or risks. The APM glossary distinguishes this provision of time or money from schedule float. Necessary review and approval activities are work that needs to be planned in their own right.

Some projects literally have items or tasks labeled as “float” in their Gantt chart. You can have it visualised in the bars or columns, but it should not be a standalone task row.

Solution: Explain What the Time Is For

I would avoid using “float” as a general label for time in a client schedule or report. Use a description that tells the reader what the time is needed for, and retain the correct technical term when you are reporting calculated float.

Name the Actual Work

If the time is required for a real activity, name that activity. The examples below show how a vague “float” label could be replaced by a description of the work, where that work genuinely needs to happen.

Instead of	Consider using, where it genuinely applies
5 days float	Final design review and comment close-out
3 days float	Commissioning readiness review
2 days float	Delivery inspection and site transfer
10 days float	Client review and approval period
5 days float	Defect rectification and verification
3 days float	Final documentation and handover review

These are examples of descriptions, not recommended durations. Estimate the time each activity actually needs and retain that duration in the schedule. If defect rectification is only a possibility, show the allowance as contingency rather than definite work.

Clear descriptions make it easier to identify who is responsible and what must be completed. “Commission and hand over” can conceal readiness checks, test records, witness attendance, operator training, manuals and as-built drawings. If those tasks are needed, show them.

For example, suppose you have allowed five working days between initial commissioning and handover. Two days are needed to review test results and three days are a contingency allowance for possible minor rectification and retesting. Show those separately. The review is planned work. The additional three days may or may not be needed.

Calling the entire five days “commissioning review” would be misleading if only two days are actually needed for the review. Calling it all “float” would hide the fact that some of the time is required work.

Only use an alternative description when it accurately describes the purpose. A longer or more impressive name does not justify an allowance.

Make the Allowance Reasonable and Visible

If you need contingency, show it and explain the risks it covers. Base it on the work, previous experience and the uncertainty involved. Consider how likely a delay is and how much it could affect completion. The analysis should suit the project; it need not always be complicated, but you should be able to explain the allowance. Avoid adding an arbitrary week just because you would prefer more time, but if there is a reasonable possibility that you will need more time, add a contingency item.

For outdoor work, that might mean an allowance for wet weather based on the location and season. As discussed in Wet Weather Delays, making these allowances visible and reporting their use helps everyone understand the schedule. Of course you should check that you have not already included the same allowance within individual task durations. Otherwise, you may count the same risk twice.

Use equally clear wording in cost reports. If an amount is cost contingency, call it that and explain its basis. “Float” is too vague to explain what the money is for.

Plan Reviews and Dependencies Properly

Allow realistic time for internal reviews, client approvals and supplier support. Agree who will do the work and check their availability. A review period is of little use if the reviewer is on leave.

Agree an approval time limit with the client and show it in the schedule. If ten working days are allowed for design review by the client, label that period clearly. Agree how overdue responses will be raised and managed.

Build the sequence from the work and dependencies, then compare it with the required finish date. Squeezing durations until they fit a target does not make the work achievable. Also find out why the project due dates are set. Understanding the reason for a deadline helps you decide where there is flexibility and where you need another delivery approach.

Be specific about the dates and whether durations mean working days or calendar days. This is another reason to clarify time based language.

Explain the Consequences of Reducing the Time

If time is genuinely unnecessary, remove it. If management or the client wants an earlier finish, review the options with them. Could reviews happen progressively? Could an approver be booked earlier? Could additional resources shorten the work?

Explain what a proposed reduction means. For example: “We can reduce the retesting allowance from three days to one, but a failed test could then delay handover.”

Record the decision, its assumptions and the remaining risk in your project communication, decision and action register. Update the schedule as work progresses, and reassess the allowance when the relevant risk has passed.

Keep Monitoring the Float

Clearer descriptions do not replace schedule analysis. Keep reviewing the critical path, activities with little remaining float, and external dependencies. Update the schedule with actual progress and realistic forecasts.

A supplier can be late without immediately moving the project finish date. The delay may consume available float instead. A report that only says “completion date unchanged” can therefore miss a growing problem.

For example: “The pump delivery is forecast three working days late. Completion is currently unchanged, but total float on the installation path has reduced from five working days to two.”

That tells the client what has changed and how much flexibility remains. Don’t wait until the float is gone before reporting the problem.

A management report can summarise upcoming work, risks and decisions while the detailed schedule retains the supporting logic and float calculations. Explain unfamiliar terms, as discussed in Make Clear Definitions, and follow any required schedule reporting format. If float or contingency must be shown separately, keep it visible.