One boundary becomes several, on several dates.

Their option, not your right

The first thing to know is who decides, because the answer is asymmetric and it surprises people who assume the contract is balanced here.

A certificate for a part is issued at the employer's sole discretion. The contractor can't require one. However convenient a partial handover would be — a finished block that could stop accruing damages, a completed section you would like off your care — asking is all you can do.

Which is a rational allocation, since taking part of an asset commits the employer to operating it, insuring it and having people in it. It is still worth knowing that you are making a request rather than exercising an entitlement, before you build a recovery plan on it.

And it changes how you ask. A request framed around your damages exposure asks them to accept a duty for your benefit. A request framed around what the part would let them start doing is the same conversation from the side they are actually weighing.

Which is worth knowing before a recovery plan leans on it. A programme that assumes a section will be handed over in March, because handing it over is obviously sensible, is a programme resting on somebody else's discretion and describing it as a date.

But their use is your route

There is one path that doesn't depend on being granted anything, and it runs through the other party's behaviour.

The employer isn't permitted to use a part of the works before a certificate has been issued for it. Where they do use one anyway, the contractor gives notice identifying the part and describing the use — and from that date the contractor stops being liable for the care of it, responsibility passes, and a certificate for that part has to issue immediately, with the outstanding work and defects listed on it.

Week 27 named this as one of the four ways a completion line gets drawn: by conduct rather than by decision. The mechanism is the point here. Use is observable, the notice is short, and it converts a fact on the ground into a certificate the employer didn't choose to issue.

Which makes noticing use a live discipline rather than a legalism. A part being used is a thing anybody on site can see, and the entitlement follows from saying so in writing at the time.

The relief is proportioned by value

Once a part is taken over, delay damages reduce — and the arithmetic of the reduction is worth doing before relying on it.

The reduction is proportional: the value of the part, set against the value of the works or the section as a whole. And the value of the part is taken after deducting the outstanding work and the defects still to be remedied on it, which is the calculation week 28 used to show that a punch list has a price. Damages for the remainder of a section that contains the part reduce as well.

So relief tracks value. It doesn't track consequence, inconvenience, or how much of the risk that part was carrying. A section worth a twentieth of the works gives you a twentieth of the relief, whether it was a car park or the thing every remaining activity was waiting behind.

That gap between value and consequence is worth holding onto, because the part an employer wants early is chosen for what it lets them do, and the part that is worth most is chosen by the bill.

Which also means the calculation moves as the list closes. Every item remedied on a taken-over part raises the value the reduction is computed on, so the relief you receive in month three isn't the relief you receive in month six, and nobody recomputes it unless you do.

Every part starts its own clock

Here is the consequence that outlasts the handover and that nobody resources.

A defects period runs from a taking-over date. Take over four parts on four dates and you have four defects periods, expiring on four different days, each covering a different set of things.

The same multiplication happens to everything else the boundary triggers. Care passes per part. Insurance obligations change per part. Retention becomes due per part. The access regime that applies to your outstanding work differs per part, because each one is a building the employer now holds and you visit.

None of that is difficult individually. What makes it hard is that it arrives at the point in the project where your team is smallest, and the person who would have tracked it has been released.

Which is week 19's round trip in a different form. Demobilisation was priced against one ending, and this phase has four.

What that does to the records

A records system designed for one event fails at four in a specific and quiet way: it keeps the last one.

A single field holding a taking-over date, a single defects expiry, one outstanding list — each of those was adequate for a single handover and silently wrong for several. The system doesn't report an error. It reports the most recent value, and everything asked of it afterwards is answered against the wrong date.

Which is week 12's argument arriving at the far end of the project. A structure that assumed one of something can't be extended to several after the records exist, and by the time a second part is taken over there are already records against the first.

The remedy is unglamorous and has to be applied before the second part exists. A field that holds one date becomes a table with one row per part, and making that change while there is one row is administration; making it when there are three is a migration with a history attached.

System design

Row one has to be opened before the first partial handover, and that is the whole difficulty. A register created after the second part exists is a register with a gap in it, which is the distinction week 12 drew between the records you can start late and the ones you can't.

Record	Produced by	Required quality	Verified against	Feeds
Parts register	You, before the first one	One row per part, opened before a partial handover is agreed	The certificates issued	Every clock that now runs per part
Defects expiry per part	You, on each certificate	Calculated and diarised, because a period ends unannounced	The certificate date it runs from	The final certificate · retention
Value and deduction per part	You, from the rates	Value less outstanding work, since that is the figure used	The outstanding list for that part	The reduction in delay damages
Care position per part	The contract, read per part	Which parts have passed and which haven't, as a list	Each certificate, or the notice of use	Exposure across the site
Note of use without a certificate	Whoever saw it, that day	Date, part, what the use was, who observed it	Nothing — it is a primary record	Whether a certificate must issue

Row five is the third entry in this dictionary with nothing to verify it against. A note that a part was in use is a primary record made by whoever was standing there, and if it wasn't made that day it doesn't exist.

Practical insight

Open a parts register the week the first partial handover is discussed, not the week it happens.

One row per part. Its certificate date. Its defects period expiry, which you calculate. Its outstanding list. Its value, and what you deducted for outstanding work. Who holds care of it. What access you have and on what terms. Seven columns, and you will be the only person on the project holding them together.

Then put your expiry dates in the diary the day each certificate issues. A defects period ends whether or not anybody notices, and what you are entitled to at the end of one — the certificate, the balance of your retention — are things you have to ask for.

And note any part you find the employer using. Date, part, what the use was, who saw it. If it already has a certificate, your note costs you nothing. If it has none, your note is the whole of the entitlement — and it exists only because somebody wrote it that day.

Key takeaways

• A certificate for a part issues at the employer’s sole discretion, so partial taking over is their option rather than your right.
• That is a rational allocation, since taking a part commits the employer to operating, insuring and occupying it.
• The employer may not use a part before a certificate has been issued for it.
• Where they do, the contractor gives notice identifying the part and the use, care passes from that date, and a certificate must issue at once with the outstanding work listed.
• So the contractor’s route to a partial handover runs through the other party’s conduct rather than through a request.
• Delay damages reduce in proportion to the value of the part against the value of the whole.
• The part’s value is taken after deducting outstanding work and defects, and damages for the remainder of a section reduce as well.
• Relief therefore tracks value rather than consequence, so a part worth a twentieth gives a twentieth however much risk it carried.
• Four parts taken over on four dates produce four defects periods expiring on four days.
• Care, insurance, retention and access all multiply the same way, at the point where the team is smallest.
• A records system holding one taking-over date doesn't report an error at the second part; it reports the most recent value.

Records born here. The parts register, one row per part · each certificate and its date · each defects period expiry, diarised · the value of each part and the deduction for outstanding work · who holds care of each · the access terms per part · any use of a part without a certificate, noted on the day.

What is coming next

Handover isn't the last test. On plant contracts a second family of tests runs afterwards, on an asset the employer is already operating.

They measure what the works actually produce rather than whether they function, they happen under the employer's control rather than yours, and failing them costs money rather than the right to hand over.