High float in Primavera P6 — what it means and what to do about it

What P6 counts

The Check Schedule Report flags any incomplete activity with total float above 44 working days. The threshold is adjustable in the report settings; 44 is the default, and the DCMA 14-point assessment that P6 took it from allows no more than 5% of activities over it.

Total float is the number of working days an activity can slip before it delays the project finish. Forty-four of them — roughly two months — is the line past which the report assumes something is missing rather than that the activity is genuinely that free.

Why it usually happens

• A missing successor. The activity has nothing after it, so P6 ties it to the project finish, and everything between now and then counts as float. This is the cause nine times out of ten.
• A successor that is the wrong one. Linking a trade to the completion milestone instead of to the activity that actually needs it done gives it the whole programme as float.
• A constraint on the successor. A "start on or after" date down the line holds the successor late, and everything feeding it inherits the slack.
• It is genuinely free. Landscaping, external works, a procurement item ordered early. Real, and rare on a fit-out.

How to find them

In the Activities view, add the Total Float column and filter on it: Total Float is greater than 44. Group by WBS and the pattern shows itself — high float clusters in one section almost always means that section was never linked forward.

For each one, look at its successors. No successors, or only the finish milestone, and you have the cause.

What to do

Link it to the activity that really depends on it. Not the finish milestone, not a section summary: the first piece of work that cannot start until this is done. Drylining to the first-fix inspection; the inspection to decoration.

If the successor is right but constrained, ask whether the constraint is a real date — a client handover, a crane booking — or a planner's note that has outlived its reason. Remove the ones that have.

If it is genuinely free, leave it and say so. A note on the activity ("external works, not on the path") is worth more than a fake link to make the number go away.

Why it matters beyond the report

A programme where half the activities carry months of float has no critical path worth the name — the path is whatever the planner typed, and the float column is fiction. When a delay is argued over, that programme cannot show what was driving what. Fixing high float is mostly fixing links, and fixed links are what make every other number in the file mean something.