Practical completion: the date everything turns on
Practical completion is the single most consequential date on a JBCC job. It hands the works over, stops the penalty clock, starts the defects period and releases the first tranche of retention, all at once.
QScope Team · 26 February 2026 · 5 min read
Practical completion is the moment the works are complete enough to be handed over and used, even if minor items remain. On a JBCC contract the principal agent certifies it, and that certificate triggers a cluster of consequences that all fire on the same date. Get the date right and everything downstream is clean.
What the date does
One certificate, several effects, and each of them is money or risk.
- Handover. The employer takes over the works and responsibility passes.
- Penalties stop. The clock on late completion penalties ends at practical completion.
- Defects period starts. The period for making good runs from this date.
- Retention releases. The first tranche of retention is freed at completion.
Minor items do not stop it
Practical completion does not mean perfect. It means the works can be used for their purpose, with outstanding minor items listed to be finished during the defects period. The judgement is whether what remains prevents use, and that is the principal agent decision. Holding completion hostage to a snag list that does not stop use only delays the retention release and keeps the penalty clock running against nobody sensible.
The defects period is not free time
From practical completion the contractor carries the obligation to make good defects that appear during the defects period. It is not a grace period, it is a warranty period with work in it. Making good on time is what unlocks the final retention release at the end, so the defects list is a commercial matter, not just a quality one.
Retention comes in two moves
The first retention tranche releases at practical completion and the balance at the end of the defects period once making good is done. Both are dates, both are contractor cash, and the second is the one that gets forgotten because it is smaller and it falls due long after the site has closed.
The habit
The day practical completion is certified, record three things against it: the penalty cut off, the defects period end date, and the two retention release dates. A handover that is not diaried this way is a handover that quietly leaves money and obligations untracked.
QScope ties retention release, the defects period and the penalty cut off to the practical completion date so nothing is missed at handover.